“XNA”的版本间的差异

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Xeno nucleic acids (XNA) are synthetic nucleic acid analogues that have a different sugar backbone than the natural nucleic acids DNA and RNA. As of 2011, at least six types of synthetic sugars have been shown to form nucleic acid backbones that can store and retrieve genetic information. Research is now being done to create synthetic polymerases to transform XNA. The study of its production and application has created a field known as xenobiology.
 
Xeno nucleic acids (XNA) are synthetic nucleic acid analogues that have a different sugar backbone than the natural nucleic acids DNA and RNA. As of 2011, at least six types of synthetic sugars have been shown to form nucleic acid backbones that can store and retrieve genetic information. Research is now being done to create synthetic polymerases to transform XNA. The study of its production and application has created a field known as xenobiology.
  
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异源核酸（XNA）是人工合成的核酸类似物，具有不同于天然核酸DNA和RNA的糖骨架。截至2011年，以证明至少有六种合成的糖能形成可存储和检索基因信息的核酸骨架。目前正在研究合成的聚合酶来转化XNA。对其生产和应用的研究创造了一个被称为异源生物学的领域。
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异源核酸（XNA）是人工合成的核酸类似物，具有不同于天然核酸DNA和RNA的糖骨架。截止至2011年，已证明至少有六种合成的糖类能形成可存储和检索基因信息的核酸骨架。目前正在研究用合成的聚合酶来转化XNA。对其生产和应用的研究创造了一个被称为异源生物学的领域。
  
 
Although the genetic information is still stored in the four canonical base pairs (unlike other [[nucleic acid analogues]]), natural DNA polymerases cannot read and duplicate this information. Thus the genetic information stored in XNA is "invisible" and therefore useless to natural DNA-based organisms.<ref name="Schmidt1">{{cite journal | vauthors = Schmidt M | title = Xenobiology: a new form of life as the ultimate biosafety tool | journal = BioEssays | volume = 32 | issue = 4 | pages = 322–331 | date = April 2010 | pmid = 20217844 | pmc = 2909387 | doi = 10.1002/bies.200900147 }}</ref>
 
Although the genetic information is still stored in the four canonical base pairs (unlike other [[nucleic acid analogues]]), natural DNA polymerases cannot read and duplicate this information. Thus the genetic information stored in XNA is "invisible" and therefore useless to natural DNA-based organisms.<ref name="Schmidt1">{{cite journal | vauthors = Schmidt M | title = Xenobiology: a new form of life as the ultimate biosafety tool | journal = BioEssays | volume = 32 | issue = 4 | pages = 322–331 | date = April 2010 | pmid = 20217844 | pmc = 2909387 | doi = 10.1002/bies.200900147 }}</ref>
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Although the genetic information is still stored in the four canonical base pairs (unlike other nucleic acid analogues), natural DNA polymerases cannot read and duplicate this information. Thus the genetic information stored in XNA is "invisible" and therefore useless to natural DNA-based organisms.
 
Although the genetic information is still stored in the four canonical base pairs (unlike other nucleic acid analogues), natural DNA polymerases cannot read and duplicate this information. Thus the genetic information stored in XNA is "invisible" and therefore useless to natural DNA-based organisms.
  
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虽然遗传信息仍然存储在四个标准碱基对(不像其他核酸类似物) ，但是天然的DNA聚合酶不能读取和复制这些信息。因此，存储在XNA中的遗传信息是“不可视的”，对于以天然DNA为基础的生物体来说是无用的。
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虽然遗传信息仍然存储在四个标准碱基对（不像其他核酸类似物那样），但是天然的DNA聚合酶不能读取和复制这些信息。因此，存储在XNA中的遗传信息是“不可视的”，对于以天然DNA为基础的生物体来说是无用的。
  
 
==Background==
 
==Background==
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The structure of DNA was discovered in 1953. Around the early 2000s, researchers created a number of exotic DNA-like structures, XNA. XNA is a synthetic polymer that can carry the same information as DNA, but with different molecular constituents. The "X" in XNA stands for "xeno," meaning stranger or alien, indicating the difference in the molecular structure as compared to DNA or RNA.
 
The structure of DNA was discovered in 1953. Around the early 2000s, researchers created a number of exotic DNA-like structures, XNA. XNA is a synthetic polymer that can carry the same information as DNA, but with different molecular constituents. The "X" in XNA stands for "xeno," meaning stranger or alien, indicating the difference in the molecular structure as compared to DNA or RNA.
  
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DNA的结构于1953年被发现。大约在21世纪初，研究人员创造了许多奇特的类DNA结构，XNA。XNA是一种人工合成的聚合物，可以携带与DNA相同的信息，但具有不同的分子成分。XNA 中的“X”代表“ xeno”，意思是外乡人或外星人，表示其分子结构与DNA或RNA相比的差异。
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DNA的结构于1953年被发现。大约在21世纪初，研究人员创造了许多奇特的类DNA结构，XNA。XNA是一种人工合成的聚合物，可以携带与DNA相同的信息，但具有不同的分子成分。XNA中的“X”代表“ xeno”，意思是外乡人或外星人，以表示其分子结构与DNA或RNA相比的差异。
  
 
Not much was done with XNA until the development of special polymerase [[enzyme]], capable of copying XNA from a DNA template as well as copying XNA back into DNA.<ref name=":1">{{Cite web |last=Gonzales |first=Robbie | name-list-style = vanc |title=XNA Is Synthetic DNA That's Stronger than the Real Thing |website=[[Io9]] |date=19 April 2012 |access-date=15 October 2015 |url=http://io9.com/5903221/meet-xna-the-first-synthetic-dna-that-evolves-like-the-real-thing}}</ref> Pinheiro et al. (2012), for example, has demonstrated such an XNA-capable polymerase that works on sequences of ~100bp in length.<ref name="Synthetic genetic polymers capable">{{cite journal | vauthors = Pinheiro VB, Taylor AI, Cozens C, Abramov M, Renders M, Zhang S, Chaput JC, Wengel J, Peak-Chew SY, McLaughlin SH, Herdewijn P, Holliger P | display-authors = 6 | title = Synthetic genetic polymers capable of heredity and evolution | journal = Science | volume = 336 | issue = 6079 | pages = 341–344 | date = April 2012 | pmid = 22517858 | pmc = 3362463 | doi = 10.1126/science.1217622 | bibcode = 2012Sci...336..341P }}</ref> More recently, synthetic biologists [[Philipp Holliger]] and Alexander Taylor managed to create XNAzymes, the XNA equivalent of a [[ribozyme]], enzymes made of DNA or ribonucleic acid. This demonstrates that XNAs not only store hereditary information, but can also serve as enzymes, raising the possibility that life elsewhere could have begun with something other than RNA or DNA.<ref>{{Cite web |website=[[Medical Research Council (United Kingdom)|Medical Research Council]] |title=World's first artificial enzymes created using synthetic biology |date=1 December 2014 |url=http://www.mrc.ac.uk/news/browse/world-s-first-artificial-enzymes-created-using-synthetic-biology/}}</ref>
 
Not much was done with XNA until the development of special polymerase [[enzyme]], capable of copying XNA from a DNA template as well as copying XNA back into DNA.<ref name=":1">{{Cite web |last=Gonzales |first=Robbie | name-list-style = vanc |title=XNA Is Synthetic DNA That's Stronger than the Real Thing |website=[[Io9]] |date=19 April 2012 |access-date=15 October 2015 |url=http://io9.com/5903221/meet-xna-the-first-synthetic-dna-that-evolves-like-the-real-thing}}</ref> Pinheiro et al. (2012), for example, has demonstrated such an XNA-capable polymerase that works on sequences of ~100bp in length.<ref name="Synthetic genetic polymers capable">{{cite journal | vauthors = Pinheiro VB, Taylor AI, Cozens C, Abramov M, Renders M, Zhang S, Chaput JC, Wengel J, Peak-Chew SY, McLaughlin SH, Herdewijn P, Holliger P | display-authors = 6 | title = Synthetic genetic polymers capable of heredity and evolution | journal = Science | volume = 336 | issue = 6079 | pages = 341–344 | date = April 2012 | pmid = 22517858 | pmc = 3362463 | doi = 10.1126/science.1217622 | bibcode = 2012Sci...336..341P }}</ref> More recently, synthetic biologists [[Philipp Holliger]] and Alexander Taylor managed to create XNAzymes, the XNA equivalent of a [[ribozyme]], enzymes made of DNA or ribonucleic acid. This demonstrates that XNAs not only store hereditary information, but can also serve as enzymes, raising the possibility that life elsewhere could have begun with something other than RNA or DNA.<ref>{{Cite web |website=[[Medical Research Council (United Kingdom)|Medical Research Council]] |title=World's first artificial enzymes created using synthetic biology |date=1 December 2014 |url=http://www.mrc.ac.uk/news/browse/world-s-first-artificial-enzymes-created-using-synthetic-biology/}}</ref>
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Not much was done with XNA until the development of special polymerase enzyme, capable of copying XNA from a DNA template as well as copying XNA back into DNA. Pinheiro et al. (2012), for example, has demonstrated such an XNA-capable polymerase that works on sequences of ~100bp in length. More recently, synthetic biologists Philipp Holliger and Alexander Taylor managed to create XNAzymes, the XNA equivalent of a ribozyme, enzymes made of DNA or ribonucleic acid. This demonstrates that XNAs not only store hereditary information, but can also serve as enzymes, raising the possibility that life elsewhere could have begun with something other than RNA or DNA.
 
Not much was done with XNA until the development of special polymerase enzyme, capable of copying XNA from a DNA template as well as copying XNA back into DNA. Pinheiro et al. (2012), for example, has demonstrated such an XNA-capable polymerase that works on sequences of ~100bp in length. More recently, synthetic biologists Philipp Holliger and Alexander Taylor managed to create XNAzymes, the XNA equivalent of a ribozyme, enzymes made of DNA or ribonucleic acid. This demonstrates that XNAs not only store hereditary information, but can also serve as enzymes, raising the possibility that life elsewhere could have begun with something other than RNA or DNA.
  
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在特殊的聚合酶被开发出来之前对XNA的研究并不多，这种酶能够以DNA为模板复制出XNA，也能将XNA复制回DNA。例如皮涅罗（Pinheiro）等人在2012年的一项研究已证明了一种可以在大约100bp序列长度上工作的XNA聚合酶。最近，合成生物学家菲利普·霍利格（Philipp Holliger）和亚历山大·泰勒（Alexander Taylor）成功地创造了XNAzymes。XNAzymes相当于核酶，由DNA或核糖核酸构成。这表明，这表明XNAs不仅存储遗传信息，还可以作为酶，这提高了其他地方的生命可能起源于RNA或DNA以外物质的可能性。
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在特殊的聚合酶被开发出来之前，对XNA的研究并不多，这种酶能够以DNA为模板复制出XNA，也能将XNA复制回DNA。例如皮涅罗（Pinheiro）等人在2012年的一项研究已证明了一种可以在大约100bp序列长度上工作的XNA聚合酶。最近，合成生物学家菲利普·霍利格（Philipp Holliger）和亚历山大·泰勒（Alexander Taylor）成功地创造了XNAzymes。XNAzymes相当于核酶，由DNA或核糖核酸构成。这表明，这表明XNAs不仅存储遗传信息，还可以作为酶，这提高了其他地方的生命可能起源于RNA或DNA以外物质的可能性。
  
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== Structure ==
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== Structure 结构 ==
 
[[File:Sugars of DNA and XNA.jpeg|thumb|369x369px|This image displays the differences in the sugar backbones used in XNAs compared to common and biologically used DNA and RNA.|链接=Special:FilePath/Sugars_of_DNA_and_XNA.jpeg]]
 
[[File:Sugars of DNA and XNA.jpeg|thumb|369x369px|This image displays the differences in the sugar backbones used in XNAs compared to common and biologically used DNA and RNA.|链接=Special:FilePath/Sugars_of_DNA_and_XNA.jpeg]]
 
Strands of DNA and RNA are formed by stringing together long chains of molecules called [[nucleotide]]s. A [[nucleotide]] is made up of three chemical components: a [[phosphate]], a five-carbon sugar group (this can be either a [[deoxyribose]] sugar—which gives us the "D" in DNA—or a [[ribose]] sugar—the "R" in RNA), and one of five standard bases ([[adenine]], [[guanine]], [[cytosine]], [[thymine]] or [[uracil]]).
 
Strands of DNA and RNA are formed by stringing together long chains of molecules called [[nucleotide]]s. A [[nucleotide]] is made up of three chemical components: a [[phosphate]], a five-carbon sugar group (this can be either a [[deoxyribose]] sugar—which gives us the "D" in DNA—or a [[ribose]] sugar—the "R" in RNA), and one of five standard bases ([[adenine]], [[guanine]], [[cytosine]], [[thymine]] or [[uracil]]).
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Strands of DNA and RNA are formed by stringing together long chains of molecules called nucleotides. A nucleotide is made up of three chemical components: a phosphate, a five-carbon sugar group (this can be either a deoxyribose sugar—which gives us the "D" in DNA—or a ribose sugar—the "R" in RNA), and one of five standard bases (adenine, guanine, cytosine, thymine or uracil).
 
Strands of DNA and RNA are formed by stringing together long chains of molecules called nucleotides. A nucleotide is made up of three chemical components: a phosphate, a five-carbon sugar group (this can be either a deoxyribose sugar—which gives us the "D" in DNA—or a ribose sugar—the "R" in RNA), and one of five standard bases (adenine, guanine, cytosine, thymine or uracil).
  
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这张图片显示了XNAs中使用的糖骨架与常见生物学上使用的DNA和RNA之间的差异。DNA链和RNA 链是由称为核苷酸的长链分子串联而成的。一个核苷酸由三种化学成分组成: 一种是磷酸盐，一种是五碳糖基(这可以是脱氧核糖糖，它在 dna 中给我们提供了“ d”，也可以是核糖糖，即 RNA 中的“ r”) ，以及五种标准碱基之一(腺嘌呤、鸟嘌呤、胞嘧啶、胸腺嘧啶或尿嘧啶)。
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这张图片显示了XNAs中使用的糖骨架与生物学中常见的DNA和RNA之间的差异。DNA链和RNA链是由名为核苷酸的长链分子串联而成的。核苷酸由三种化学成分组成：磷酸、五碳糖（可以是脱氧核糖，它给DNA提供了“D”，也可以是核糖，即RNA中的“R”) 、以及五种标准碱基之一（腺嘌呤、鸟嘌呤、胞嘧啶、胸腺嘧啶或尿嘧啶）。
  
 
The molecules that piece together to form the six xeno nucleic acids are almost identical to those of DNA and RNA, with one exception: in XNA [[nucleotide]]s, the [[deoxyribose]] and [[ribose]] sugar groups of DNA and RNA have been replaced with other chemical structures. These substitutions make XNAs functionally and structurally analogous to DNA and RNA despite being unnatural and artificial.
 
The molecules that piece together to form the six xeno nucleic acids are almost identical to those of DNA and RNA, with one exception: in XNA [[nucleotide]]s, the [[deoxyribose]] and [[ribose]] sugar groups of DNA and RNA have been replaced with other chemical structures. These substitutions make XNAs functionally and structurally analogous to DNA and RNA despite being unnatural and artificial.
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The molecules that piece together to form the six xeno nucleic acids are almost identical to those of DNA and RNA, with one exception: in XNA nucleotides, the deoxyribose and ribose sugar groups of DNA and RNA have been replaced with other chemical structures. These substitutions make XNAs functionally and structurally analogous to DNA and RNA despite being unnatural and artificial.
 
The molecules that piece together to form the six xeno nucleic acids are almost identical to those of DNA and RNA, with one exception: in XNA nucleotides, the deoxyribose and ribose sugar groups of DNA and RNA have been replaced with other chemical structures. These substitutions make XNAs functionally and structurally analogous to DNA and RNA despite being unnatural and artificial.
  
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组成六种核酸的分子与 DNA 和 RNA 的分子几乎完全相同，只有一个例外: 在 XNA 核苷酸中，DNA 和 RNA 的脱氧核糖和核糖糖基被其他化学结构所取代。这些替换使得转录因子在功能和结构上与 DNA 和 RNA 相似，尽管它们是非自然的和人工的。
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组成这六种异源核酸的分子与DNA和RNA的分子几乎完全相同，只有一处例外：在XNA核苷酸中，DNA和RNA的脱氧核糖和核糖被其他化学结构所取代。这些替换使得XNAs功能和结构上与DNA和RNA相似，尽管它们是非自然的、人工的。
  
 
XNA exhibits a variety of structural chemical changes relative to its natural counterparts. Types of synthetic XNA created so far include:<ref name="Schmidt1" />
 
XNA exhibits a variety of structural chemical changes relative to its natural counterparts. Types of synthetic XNA created so far include:<ref name="Schmidt1" />
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* FANA (Fluoro Arabino nucleic acid)
 
* FANA (Fluoro Arabino nucleic acid)
  
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XNA 表现出各种结构的化学变化相对于它的天然同行。迄今为止合成的 XNA 类型包括:  
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XNA相对于DNA和RNA能表现出各种结构上的化学变化。迄今为止合成的XNA类型包括:  
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* 1,5- 脱水己醇核酸(HNA)
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* 1,5-脱水己醇核酸（HNA）
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* 环己烯核酸(CeNA)
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* 环己烯核酸（CeNA）
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* 苏糖核酸(TNA)
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* 苏糖核酸（TNA）
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* GNA (GNA)
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* 乙二醇核酸（GNA）
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* 锁核酸()
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* 锁核酸（LNA）
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* 肽核酸(PNA)
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* 肽核酸（PNA）
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* FANA (氟阿拉伯氨基核酸)
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* 2氟-阿拉伯糖核酸（FANA）
  
 
HNA could be used to potentially act as a drug that can recognize and bind to specified sequences. Scientists have been able to isolate HNAs for the possible binding of sequences that target HIV.<ref>{{Cite web |title = Polymers perform non-DNA evolution |url = http://www.rsc.org/chemistryworld/News/2012/April/xna-hna-primordial-life-dna-evolution-chemistry.asp |first=Andy |last=Extance | name-list-style = vanc |date=19 April 2012 |website = [[Royal Society of Chemistry]] |access-date = 15 October 2015}}</ref> With cyclohexene nucleic acid, research has shown that CeNAs with stereochemistry similar to the D form can create stable duplexes with itself and RNA. It was shown that CeNAs are not as stable when they form duplexes with DNA.<ref>{{cite journal | vauthors = Gu P, Schepers G, Rozenski J, Van Aerschot A, Herdewijn P | title = Base pairing properties of D- and L-cyclohexene nucleic acids (CeNA) | journal = Oligonucleotides | volume = 13 | issue = 6 | pages = 479–489 | year = 2003 | pmid = 15025914 | doi = 10.1089/154545703322860799 }}</ref>
 
HNA could be used to potentially act as a drug that can recognize and bind to specified sequences. Scientists have been able to isolate HNAs for the possible binding of sequences that target HIV.<ref>{{Cite web |title = Polymers perform non-DNA evolution |url = http://www.rsc.org/chemistryworld/News/2012/April/xna-hna-primordial-life-dna-evolution-chemistry.asp |first=Andy |last=Extance | name-list-style = vanc |date=19 April 2012 |website = [[Royal Society of Chemistry]] |access-date = 15 October 2015}}</ref> With cyclohexene nucleic acid, research has shown that CeNAs with stereochemistry similar to the D form can create stable duplexes with itself and RNA. It was shown that CeNAs are not as stable when they form duplexes with DNA.<ref>{{cite journal | vauthors = Gu P, Schepers G, Rozenski J, Van Aerschot A, Herdewijn P | title = Base pairing properties of D- and L-cyclohexene nucleic acids (CeNA) | journal = Oligonucleotides | volume = 13 | issue = 6 | pages = 479–489 | year = 2003 | pmid = 15025914 | doi = 10.1089/154545703322860799 }}</ref>
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HNA could be used to potentially act as a drug that can recognize and bind to specified sequences. Scientists have been able to isolate HNAs for the possible binding of sequences that target HIV. With cyclohexene nucleic acid, research has shown that CeNAs with stereochemistry similar to the D form can create stable duplexes with itself and RNA. It was shown that CeNAs are not as stable when they form duplexes with DNA.
 
HNA could be used to potentially act as a drug that can recognize and bind to specified sequences. Scientists have been able to isolate HNAs for the possible binding of sequences that target HIV. With cyclohexene nucleic acid, research has shown that CeNAs with stereochemistry similar to the D form can create stable duplexes with itself and RNA. It was shown that CeNAs are not as stable when they form duplexes with DNA.
  
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海航可能被用来作为一种潜在的药物，可以识别和结合特定的序列。科学家已经能够分离出可能与艾滋病毒相关的基因序列。利用环己烯核酸，研究表明，具有类似 d 型立体化学结构的二茂铁可以与自身和 RNA 形成稳定的复配体。结果表明，当 CeNAs 与 DNA 形成双链时，CeNAs 不是很稳定。
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HNA可被用作识别和结合特定序列的药物。科学家已经能够分离出HNAs，以靶向结合艾滋病毒相关的基因序列。研究表明，在存在环己烯核酸的情况下，具有类似D型立体化学结构的CeNAs可以与自身和RNA形成稳定的双链体。结果表明，当CeNAs与DNA形成双链体时，CeNAs不是很稳定。
  
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==Implications==
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==Implications启示==
 
The study of XNA is not intended to give scientists a better understanding of biological [[evolution]] as it has occurred historically, but rather to explore ways in which we can control and even reprogram the genetic makeup of biological organisms moving forward. XNA has shown significant potential in solving the current issue of [[genetic pollution]] in [[genetically modified organism]]s.<ref>{{cite journal | vauthors = Herdewijn P, Marlière P | title = Toward safe genetically modified organisms through the chemical diversification of nucleic acids | journal = Chemistry & Biodiversity | volume = 6 | issue = 6 | pages = 791–808 | date = June 2009 | pmid = 19554563 | doi = 10.1002/cbdv.200900083 | s2cid = 8572188 }}</ref> While DNA is incredibly efficient in its ability to store genetic information and lend complex biological diversity, its four-letter genetic alphabet is relatively limited. Using a genetic code of six XNAs rather than the four naturally occurring DNA nucleotide bases yields endless opportunities for genetic modification and expansion of chemical functionality.<ref>{{cite journal | vauthors = Pinheiro VB, Holliger P | title = The XNA world: progress towards replication and evolution of synthetic genetic polymers | journal = Current Opinion in Chemical Biology | volume = 16 | issue = 3–4 | pages = 245–252 | date = August 2012 | pmid = 22704981 | doi = 10.1016/j.cbpa.2012.05.198 }}</ref>
 
The study of XNA is not intended to give scientists a better understanding of biological [[evolution]] as it has occurred historically, but rather to explore ways in which we can control and even reprogram the genetic makeup of biological organisms moving forward. XNA has shown significant potential in solving the current issue of [[genetic pollution]] in [[genetically modified organism]]s.<ref>{{cite journal | vauthors = Herdewijn P, Marlière P | title = Toward safe genetically modified organisms through the chemical diversification of nucleic acids | journal = Chemistry & Biodiversity | volume = 6 | issue = 6 | pages = 791–808 | date = June 2009 | pmid = 19554563 | doi = 10.1002/cbdv.200900083 | s2cid = 8572188 }}</ref> While DNA is incredibly efficient in its ability to store genetic information and lend complex biological diversity, its four-letter genetic alphabet is relatively limited. Using a genetic code of six XNAs rather than the four naturally occurring DNA nucleotide bases yields endless opportunities for genetic modification and expansion of chemical functionality.<ref>{{cite journal | vauthors = Pinheiro VB, Holliger P | title = The XNA world: progress towards replication and evolution of synthetic genetic polymers | journal = Current Opinion in Chemical Biology | volume = 16 | issue = 3–4 | pages = 245–252 | date = August 2012 | pmid = 22704981 | doi = 10.1016/j.cbpa.2012.05.198 }}</ref>
  
 
The study of XNA is not intended to give scientists a better understanding of biological evolution as it has occurred historically, but rather to explore ways in which we can control and even reprogram the genetic makeup of biological organisms moving forward. XNA has shown significant potential in solving the current issue of genetic pollution in genetically modified organisms. While DNA is incredibly efficient in its ability to store genetic information and lend complex biological diversity, its four-letter genetic alphabet is relatively limited. Using a genetic code of six XNAs rather than the four naturally occurring DNA nucleotide bases yields endless opportunities for genetic modification and expansion of chemical functionality.
 
The study of XNA is not intended to give scientists a better understanding of biological evolution as it has occurred historically, but rather to explore ways in which we can control and even reprogram the genetic makeup of biological organisms moving forward. XNA has shown significant potential in solving the current issue of genetic pollution in genetically modified organisms. While DNA is incredibly efficient in its ability to store genetic information and lend complex biological diversity, its four-letter genetic alphabet is relatively limited. Using a genetic code of six XNAs rather than the four naturally occurring DNA nucleotide bases yields endless opportunities for genetic modification and expansion of chemical functionality.
  
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这项研究的目的不是让科学家更好地了解历史上发生过的生物进化，而是探索我们能够控制甚至重新编程生物有机体基因组成的方法。XNA 在解决目前转基因生物的遗传污染问题上显示出巨大的潜力。尽管 DNA 在储存遗传信息和提供复杂生物多样性方面具有令人难以置信的效率，但其四个字母的遗传字母相对有限。使用6个转录因子的遗传密码，而不是4个自然产生的 DNA 核苷酸碱基，可以产生无限的基因工程和扩展化学功能的机会。
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XNA研究的目的不是为了让科学家更好地了解历史上发生过的生物进化，而是探索我们能够控制甚至重新编程生物体基因组成的方法。XNA在解决目前转基因生物的遗传污染问题上显示出巨大潜力。尽管DNA在储存遗传信息和提供复杂生物多样性方面具有令人难以置信的效率，但其四个字母的遗传密码表相对有限。使用6个XNAs的遗传密码而不是4个自然产生的DNA碱基，或将展现出基因修饰和扩展化学功能的无尽机遇。
  
 
The development of various hypotheses and theories about XNAs have altered a key factor in our current understanding of nucleic acids: that [[heredity]] and evolution are not limited to DNA and RNA as once thought, but are simply processes that have developed from polymers capable of storing information.<ref name="Synthetic genetic polymers capable"/> Investigations into XNAs will allow for researchers to assess whether DNA and RNA are the most efficient and desirable building blocks of life, or if these two molecules were chosen randomly after evolving from a larger class of chemical ancestors.<ref>{{cite journal | vauthors = Hunter P | title = XNA marks the spot. What can we learn about the origins of life and the treatment of disease through artificial nucleic acids? | journal = EMBO Reports | volume = 14 | issue = 5 | pages = 410–413 | date = May 2013 | pmid = 23579343 | pmc = 3642382 | doi = 10.1038/embor.2013.42 }}</ref>
 
The development of various hypotheses and theories about XNAs have altered a key factor in our current understanding of nucleic acids: that [[heredity]] and evolution are not limited to DNA and RNA as once thought, but are simply processes that have developed from polymers capable of storing information.<ref name="Synthetic genetic polymers capable"/> Investigations into XNAs will allow for researchers to assess whether DNA and RNA are the most efficient and desirable building blocks of life, or if these two molecules were chosen randomly after evolving from a larger class of chemical ancestors.<ref>{{cite journal | vauthors = Hunter P | title = XNA marks the spot. What can we learn about the origins of life and the treatment of disease through artificial nucleic acids? | journal = EMBO Reports | volume = 14 | issue = 5 | pages = 410–413 | date = May 2013 | pmid = 23579343 | pmc = 3642382 | doi = 10.1038/embor.2013.42 }}</ref>
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The development of various hypotheses and theories about XNAs have altered a key factor in our current understanding of nucleic acids: that heredity and evolution are not limited to DNA and RNA as once thought, but are simply processes that have developed from polymers capable of storing information. Investigations into XNAs will allow for researchers to assess whether DNA and RNA are the most efficient and desirable building blocks of life, or if these two molecules were chosen randomly after evolving from a larger class of chemical ancestors.
 
The development of various hypotheses and theories about XNAs have altered a key factor in our current understanding of nucleic acids: that heredity and evolution are not limited to DNA and RNA as once thought, but are simply processes that have developed from polymers capable of storing information. Investigations into XNAs will allow for researchers to assess whether DNA and RNA are the most efficient and desirable building blocks of life, or if these two molecules were chosen randomly after evolving from a larger class of chemical ancestors.
  
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关于转录因子的各种假说和理论的发展已经改变了我们目前对核酸的理解中的一个关键因素: 遗传和进化并不像人们曾经认为的那样仅仅局限于 DNA 和 RNA，而只是从能够储存信息的聚合物发展而来的简单过程。对于转录因子的研究将允许研究人员评估 DNA 和 RNA 是否是最有效和最理想的生命基石，或者这两个分子是否是从一个更大的化学祖先进化而来的随机选择。
+
关于XNAs的各种假说和理论的发展已经改变了目前我们理解核酸的一个关键点: 遗传和进化并不是人们曾经认为的那样只局限于DNA和RNA，而仅仅是一种起源于能够储存信息的聚合物的简单过程。对于XNAs的研究将允许研究人员评估DNA和RNA是不是最有效和最理想的生命构件，或者这两种分子是不是在更大类的化学祖先进化之后被随机地选择出来的。
  
 
== Applications ==
 
== Applications ==
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One theory of XNA utilization is its incorporation into medicine as a disease-fighting agent. Some enzymes and antibodies that are currently administered for various disease treatments are broken down too quickly in the stomach or bloodstream. Because XNA is foreign and because it is believed that humans have not yet evolved the enzymes to break them down, XNAs may be able to serve as a more durable counterpart to the DNA and RNA-based treatment methodologies that are currently in use.
 
One theory of XNA utilization is its incorporation into medicine as a disease-fighting agent. Some enzymes and antibodies that are currently administered for various disease treatments are broken down too quickly in the stomach or bloodstream. Because XNA is foreign and because it is believed that humans have not yet evolved the enzymes to break them down, XNAs may be able to serve as a more durable counterpart to the DNA and RNA-based treatment methodologies that are currently in use.
  
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= = 应用 = = 利用 XNA 的一种理论是将其作为抗病剂纳入医学。目前用于各种疾病治疗的一些酶和抗体在胃或血液中分解得太快。由于 XNA 是外来的，而且据信人类尚未进化出能够分解它们的酶，因此 XNA 可能成为目前正在使用的 DNA 和 rna 治疗方法的更持久的对应物。
+
= = 应用 = = 一种利用XNA的理论是将其作为抗病剂纳入医学。目前，一些用于各种疾病治疗的酶和抗体在胃或血液中分解得太快。但由于XNA是外来的，而且人类尚未进化出能够分解它们的酶，因此对于目前正在使用的DNA和RNA治疗方法，XNA可能成为比它们更持久的替换物。
  
 
Experiments with XNA have already allowed for the replacement and enlargement of this genetic alphabet, and XNAs have shown [[Complementarity (molecular biology)|complementarity]] with DNA and RNA nucleotides, suggesting potential for its transcription and recombination. One experiment conducted at the University of Florida led to the production of an XNA [[aptamer]] by the AEGIS-SELEX (artificially expanded genetic information system - systematic evolution of [[ligand]]s by exponential enrichment) method, followed by successful binding to a line of [[breast cancer]] cells.<ref>{{cite journal | vauthors = Sefah K, Yang Z, Bradley KM, Hoshika S, Jiménez E, Zhang L, Zhu G, Shanker S, Yu F, Turek D, Tan W, Benner SA | display-authors = 6 | title = In vitro selection with artificial expanded genetic information systems | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 111 | issue = 4 | pages = 1449–1454 | date = January 2014 | pmid = 24379378 | pmc = 3910645 | doi = 10.1073/pnas.1311778111 | doi-access = free | bibcode = 2014PNAS..111.1449S }}</ref> Furthermore, experiments in the model bacterium ''[[Escherichia coli|E. coli]]'' have demonstrated the ability for XNA to serve as a biological template for DNA ''[[in vivo]].''<ref>{{cite journal | vauthors = Pezo V, Liu FW, Abramov M, Froeyen M, Herdewijn P, Marlière P | title = Binary genetic cassettes for selecting XNA-templated DNA synthesis in vivo | journal = Angewandte Chemie | volume = 52 | issue = 31 | pages = 8139–8143 | date = July 2013 | pmid = 23804524 | doi = 10.1002/anie.201303288 | url = https://lirias.kuleuven.be/handle/123456789/413046 }}</ref>
 
Experiments with XNA have already allowed for the replacement and enlargement of this genetic alphabet, and XNAs have shown [[Complementarity (molecular biology)|complementarity]] with DNA and RNA nucleotides, suggesting potential for its transcription and recombination. One experiment conducted at the University of Florida led to the production of an XNA [[aptamer]] by the AEGIS-SELEX (artificially expanded genetic information system - systematic evolution of [[ligand]]s by exponential enrichment) method, followed by successful binding to a line of [[breast cancer]] cells.<ref>{{cite journal | vauthors = Sefah K, Yang Z, Bradley KM, Hoshika S, Jiménez E, Zhang L, Zhu G, Shanker S, Yu F, Turek D, Tan W, Benner SA | display-authors = 6 | title = In vitro selection with artificial expanded genetic information systems | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 111 | issue = 4 | pages = 1449–1454 | date = January 2014 | pmid = 24379378 | pmc = 3910645 | doi = 10.1073/pnas.1311778111 | doi-access = free | bibcode = 2014PNAS..111.1449S }}</ref> Furthermore, experiments in the model bacterium ''[[Escherichia coli|E. coli]]'' have demonstrated the ability for XNA to serve as a biological template for DNA ''[[in vivo]].''<ref>{{cite journal | vauthors = Pezo V, Liu FW, Abramov M, Froeyen M, Herdewijn P, Marlière P | title = Binary genetic cassettes for selecting XNA-templated DNA synthesis in vivo | journal = Angewandte Chemie | volume = 52 | issue = 31 | pages = 8139–8143 | date = July 2013 | pmid = 23804524 | doi = 10.1002/anie.201303288 | url = https://lirias.kuleuven.be/handle/123456789/413046 }}</ref>
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Experiments with XNA have already allowed for the replacement and enlargement of this genetic alphabet, and XNAs have shown complementarity with DNA and RNA nucleotides, suggesting potential for its transcription and recombination. One experiment conducted at the University of Florida led to the production of an XNA aptamer by the AEGIS-SELEX (artificially expanded genetic information system - systematic evolution of ligands by exponential enrichment) method, followed by successful binding to a line of breast cancer cells. Furthermore, experiments in the model bacterium E. coli have demonstrated the ability for XNA to serve as a biological template for DNA in vivo.
 
Experiments with XNA have already allowed for the replacement and enlargement of this genetic alphabet, and XNAs have shown complementarity with DNA and RNA nucleotides, suggesting potential for its transcription and recombination. One experiment conducted at the University of Florida led to the production of an XNA aptamer by the AEGIS-SELEX (artificially expanded genetic information system - systematic evolution of ligands by exponential enrichment) method, followed by successful binding to a line of breast cancer cells. Furthermore, experiments in the model bacterium E. coli have demonstrated the ability for XNA to serve as a biological template for DNA in vivo.
  
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用 XNA 进行的实验已经可以替换和扩大这个基因字母表，而且 XNA 已经显示出与 DNA 和 RNA 核苷酸的互补性，这表明它具有转录和重组的潜力。在佛罗里达大学进行的一项实验中，人工扩增的基因信息系统-配体指数增强系统进化技术-人工合成方法产生了一种 XNA 适配子，并成功地与一系列乳腺癌细胞结合。此外，在模型细菌大肠杆菌中的实验表明，XNA 具有在体内作为 DNA 生物模板的能力。
+
XNA实验已经可以替换和扩大遗传密码表，而且XNA已经显示出与DNA和RNA核苷酸的互补性，这表明它具有转录和重组的潜力。在佛罗里达大学进行的一项实验中，通过AEISIS-SELEX（人工扩增的遗传信息系统——通过指数富集的配体的系统进化）产生了一种XNA适配体，并成功与乳腺癌细胞系结合。此外，在大肠杆菌中的实验表明，XNA在体内具有作为DNA生物模板的能力。
  
 
In moving forward with genetic research on XNAs, various questions must come into consideration regarding [[biosafety]], [[biosecurity]], ethics, and governance/regulation.<ref name="Schmidt1" /> One of the key questions here is whether XNA in an ''in vivo'' setting would intermix with DNA and RNA in its natural environment, thereby rendering scientists unable to control or predict its implications in genetic [[mutation]].<ref name=":0" />
 
In moving forward with genetic research on XNAs, various questions must come into consideration regarding [[biosafety]], [[biosecurity]], ethics, and governance/regulation.<ref name="Schmidt1" /> One of the key questions here is whether XNA in an ''in vivo'' setting would intermix with DNA and RNA in its natural environment, thereby rendering scientists unable to control or predict its implications in genetic [[mutation]].<ref name=":0" />
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In moving forward with genetic research on XNAs, various questions must come into consideration regarding biosafety, biosecurity, ethics, and governance/regulation. One of the key questions here is whether XNA in an in vivo setting would intermix with DNA and RNA in its natural environment, thereby rendering scientists unable to control or predict its implications in genetic mutation.
 
In moving forward with genetic research on XNAs, various questions must come into consideration regarding biosafety, biosecurity, ethics, and governance/regulation. One of the key questions here is whether XNA in an in vivo setting would intermix with DNA and RNA in its natural environment, thereby rendering scientists unable to control or predict its implications in genetic mutation.
  
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在推进对转录因子的基因研究时，必须考虑到有关生物安全、生物安保、伦理和治理/监管的各种问题。这里的一个关键问题是，在体内环境中，XNA 是否会与自然环境中的 DNA 和 RNA 混合，从而使科学家无法控制或预测其在基因突变中的含义。
+
在推进对XNAs的基因研究时，必须考虑到有关生物安全、生物防护、伦理和治理/监管的各种问题。这里的一个关键问题是，在体内环境中，XNA是否会与自然环境中的DNA和RNA混合，从而使科学家无法控制或预测其在基因突变中可能的影响。
  
 
XNA also has potential applications to be used as [[Catalysis|catalysts]], much like RNA has the ability to be used as an [[enzyme]]. Researchers have shown XNA is able to cleave and [[Ligation (molecular biology)|ligate]] DNA, RNA and other XNA sequences, with the most activity being XNA catalyzed reactions on XNA molecules. This research may be used in determining whether DNA and RNA's role in life emerged through natural selection processes or if it was simply a coincidental occurrence.<ref>{{cite journal | vauthors = Taylor AI, Pinheiro VB, Smola MJ, Morgunov AS, Peak-Chew S, Cozens C, Weeks KM, Herdewijn P, Holliger P | display-authors = 6 | title = Catalysts from synthetic genetic polymers | journal = Nature | volume = 518 | issue = 7539 | pages = 427–430 | date = February 2015 | pmid = 25470036 | pmc = 4336857 | doi = 10.1038/nature13982 | bibcode = 2015Natur.518..427T }}</ref>
 
XNA also has potential applications to be used as [[Catalysis|catalysts]], much like RNA has the ability to be used as an [[enzyme]]. Researchers have shown XNA is able to cleave and [[Ligation (molecular biology)|ligate]] DNA, RNA and other XNA sequences, with the most activity being XNA catalyzed reactions on XNA molecules. This research may be used in determining whether DNA and RNA's role in life emerged through natural selection processes or if it was simply a coincidental occurrence.<ref>{{cite journal | vauthors = Taylor AI, Pinheiro VB, Smola MJ, Morgunov AS, Peak-Chew S, Cozens C, Weeks KM, Herdewijn P, Holliger P | display-authors = 6 | title = Catalysts from synthetic genetic polymers | journal = Nature | volume = 518 | issue = 7539 | pages = 427–430 | date = February 2015 | pmid = 25470036 | pmc = 4336857 | doi = 10.1038/nature13982 | bibcode = 2015Natur.518..427T }}</ref>
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XNA also has potential applications to be used as catalysts, much like RNA has the ability to be used as an enzyme. Researchers have shown XNA is able to cleave and ligate DNA, RNA and other XNA sequences, with the most activity being XNA catalyzed reactions on XNA molecules. This research may be used in determining whether DNA and RNA's role in life emerged through natural selection processes or if it was simply a coincidental occurrence.
 
XNA also has potential applications to be used as catalysts, much like RNA has the ability to be used as an enzyme. Researchers have shown XNA is able to cleave and ligate DNA, RNA and other XNA sequences, with the most activity being XNA catalyzed reactions on XNA molecules. This research may be used in determining whether DNA and RNA's role in life emerged through natural selection processes or if it was simply a coincidental occurrence.
  
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XNA 也有潜在的应用可以用作催化剂，就像 RNA 可以用作酶一样。研究人员已经表明，XNA 能够切割和连接 DNA、 RNA 和其他 XNA 序列，其中最活跃的是 XNA 对 XNA 分子的催化反应。这项研究可以用来确定 DNA 和 RNA 在生命中的作用是通过自然选择过程还是仅仅是一个巧合。
+
XNA还可以作催化剂，就像RNA可以当作酶一样。研究人员已经证明，XNA能够剪切和连接DNA、RNA和其他XNA序列，其中XNA对XNA分子的催化反应最具活性。这项研究可以用来确定DNA和RNA在生命中的作用是通过自然选择过程产生的，还是说仅仅是一个巧合。
  
 
XNA may be employed as molecular clamps in [[quantitative real-time polymerase chain reaction]]s (qPCR) by hybridizing with target DNA sequences.<ref name="A novel xenonucleic acid-mediated m">{{cite journal | vauthors = Sun Q, Pastor L, Du J, Powell MJ, Zhang A, Bodmer W, Wu J, Zheng S, Sha MY | display-authors = 6 | title = A novel xenonucleic acid-mediated molecular clamping technology for early colorectal cancer screening | journal = PLOS ONE | volume = 16 | issue = 10 | pages = e0244332 | date = 2021-10-05 | pmid = 34610014 | pmc = 8491914 | doi = 10.1371/journal.pone.0244332 | bibcode = 2021PLoSO..1644332S | doi-access = free }}</ref> In a study published in [[PLOS One|PLOS ONE]], an XNA-mediated molecular clamping assay detected mutant cell-free DNA (cfDNA) from precancerous [[colorectal cancer]] (CRC) lesions and colorectal cancer.<ref name="A novel xenonucleic acid-mediated m"/> XNA may also act as highly specific molecular probes for detection of nucleic acid target sequence.<ref>{{cite journal | vauthors = D'Agata R, Giuffrida MC, Spoto G | title = Peptide Nucleic Acid-Based Biosensors for Cancer Diagnosis | journal = Molecules | volume = 22 | issue = 11 | pages = 1951 | date = November 2017 | pmid = 29137122 | doi = 10.3390/molecules22111951 | pmc = 6150339 | doi-access = free }}</ref>
 
XNA may be employed as molecular clamps in [[quantitative real-time polymerase chain reaction]]s (qPCR) by hybridizing with target DNA sequences.<ref name="A novel xenonucleic acid-mediated m">{{cite journal | vauthors = Sun Q, Pastor L, Du J, Powell MJ, Zhang A, Bodmer W, Wu J, Zheng S, Sha MY | display-authors = 6 | title = A novel xenonucleic acid-mediated molecular clamping technology for early colorectal cancer screening | journal = PLOS ONE | volume = 16 | issue = 10 | pages = e0244332 | date = 2021-10-05 | pmid = 34610014 | pmc = 8491914 | doi = 10.1371/journal.pone.0244332 | bibcode = 2021PLoSO..1644332S | doi-access = free }}</ref> In a study published in [[PLOS One|PLOS ONE]], an XNA-mediated molecular clamping assay detected mutant cell-free DNA (cfDNA) from precancerous [[colorectal cancer]] (CRC) lesions and colorectal cancer.<ref name="A novel xenonucleic acid-mediated m"/> XNA may also act as highly specific molecular probes for detection of nucleic acid target sequence.<ref>{{cite journal | vauthors = D'Agata R, Giuffrida MC, Spoto G | title = Peptide Nucleic Acid-Based Biosensors for Cancer Diagnosis | journal = Molecules | volume = 22 | issue = 11 | pages = 1951 | date = November 2017 | pmid = 29137122 | doi = 10.3390/molecules22111951 | pmc = 6150339 | doi-access = free }}</ref>
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XNA may be employed as molecular clamps in quantitative real-time polymerase chain reactions (qPCR) by hybridizing with target DNA sequences. In a study published in PLOS ONE, an XNA-mediated molecular clamping assay detected mutant cell-free DNA (cfDNA) from precancerous colorectal cancer (CRC) lesions and colorectal cancer. XNA may also act as highly specific molecular probes for detection of nucleic acid target sequence.
 
XNA may be employed as molecular clamps in quantitative real-time polymerase chain reactions (qPCR) by hybridizing with target DNA sequences. In a study published in PLOS ONE, an XNA-mediated molecular clamping assay detected mutant cell-free DNA (cfDNA) from precancerous colorectal cancer (CRC) lesions and colorectal cancer. XNA may also act as highly specific molecular probes for detection of nucleic acid target sequence.
  
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XNA 可以作为定量实时聚合酶链反应(qPCR)的分子钳，与靶 DNA 序列杂交。在《公共科学图书馆 · 综合》杂志上发表的一项研究中，一种 DNA 介导的分子钳技术检测到了癌前病变大肠癌和大肠癌的无细胞 DNA 突变体。XNA 还可以作为高度特异性的分子探针公司，用于检测核酸靶序列。
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XNA可以通过与靶DNA序列杂交，作为定量实时聚合酶链式反应（qPCR）的分子钳。在《公共科学图书馆》（PLOS ONE）期刊上发表的一项研究中，一种DNA介导的分子钳技术检测到了癌前结直肠癌 (CRC)病变和结直肠癌的突变无细胞DNA（cfDNA）。XNA还可以作为检测核酸靶序列的高特异性分子探针。
  
 
== See also ==
 
== See also ==
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* Xenobiology
 
* Xenobiology
  
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= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 核酸类似物生物学
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= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 核酸类似物 异源生物学
  
 
== References ==
 
== References ==

2022年3月20日 (日) 16:20的版本

本词条由余凡尘初步翻译

此词条暂由彩云小译翻译，翻译字数共1157，未经人工整理和审校，带来阅读不便，请见谅。

Glycol nucleic acid (left) is an example of a xeno nucleic acid because it has a different backbone than DNA (right).

Xeno nucleic acids (XNA) are synthetic nucleic acid analogues that have a different sugar backbone than the natural nucleic acids DNA and RNA.[1] As of 2011, at least six types of synthetic sugars have been shown to form nucleic acid backbones that can store and retrieve genetic information. Research is now being done to create synthetic polymerases to transform XNA. The study of its production and application has created a field known as xenobiology.


Xeno nucleic acids (XNA) are synthetic nucleic acid analogues that have a different sugar backbone than the natural nucleic acids DNA and RNA. As of 2011, at least six types of synthetic sugars have been shown to form nucleic acid backbones that can store and retrieve genetic information. Research is now being done to create synthetic polymerases to transform XNA. The study of its production and application has created a field known as xenobiology.

异源核酸（XNA）是人工合成的核酸类似物，具有不同于天然核酸DNA和RNA的糖骨架。截止至2011年，已证明至少有六种合成的糖类能形成可存储和检索基因信息的核酸骨架。目前正在研究用合成的聚合酶来转化XNA。对其生产和应用的研究创造了一个被称为异源生物学的领域。

Although the genetic information is still stored in the four canonical base pairs (unlike other nucleic acid analogues), natural DNA polymerases cannot read and duplicate this information. Thus the genetic information stored in XNA is "invisible" and therefore useless to natural DNA-based organisms.[2]

Although the genetic information is still stored in the four canonical base pairs (unlike other nucleic acid analogues), natural DNA polymerases cannot read and duplicate this information. Thus the genetic information stored in XNA is "invisible" and therefore useless to natural DNA-based organisms.

虽然遗传信息仍然存储在四个标准碱基对（不像其他核酸类似物那样），但是天然的DNA聚合酶不能读取和复制这些信息。因此，存储在XNA中的遗传信息是“不可视的”，对于以天然DNA为基础的生物体来说是无用的。

Background

The structure of DNA was discovered in 1953. Around the early 2000s, researchers created a number of exotic DNA-like structures, XNA. XNA is a synthetic polymer that can carry the same information as DNA, but with different molecular constituents. The "X" in XNA stands for "xeno," meaning stranger or alien, indicating the difference in the molecular structure as compared to DNA or RNA.[3]

The structure of DNA was discovered in 1953. Around the early 2000s, researchers created a number of exotic DNA-like structures, XNA. XNA is a synthetic polymer that can carry the same information as DNA, but with different molecular constituents. The "X" in XNA stands for "xeno," meaning stranger or alien, indicating the difference in the molecular structure as compared to DNA or RNA.

DNA的结构于1953年被发现。大约在21世纪初，研究人员创造了许多奇特的类DNA结构，XNA。XNA是一种人工合成的聚合物，可以携带与DNA相同的信息，但具有不同的分子成分。XNA中的“X”代表“ xeno”，意思是外乡人或外星人，以表示其分子结构与DNA或RNA相比的差异。

Not much was done with XNA until the development of special polymerase enzyme, capable of copying XNA from a DNA template as well as copying XNA back into DNA.[3] Pinheiro et al. (2012), for example, has demonstrated such an XNA-capable polymerase that works on sequences of ~100bp in length.[4] More recently, synthetic biologists Philipp Holliger and Alexander Taylor managed to create XNAzymes, the XNA equivalent of a ribozyme, enzymes made of DNA or ribonucleic acid. This demonstrates that XNAs not only store hereditary information, but can also serve as enzymes, raising the possibility that life elsewhere could have begun with something other than RNA or DNA.[5]

Not much was done with XNA until the development of special polymerase enzyme, capable of copying XNA from a DNA template as well as copying XNA back into DNA. Pinheiro et al. (2012), for example, has demonstrated such an XNA-capable polymerase that works on sequences of ~100bp in length. More recently, synthetic biologists Philipp Holliger and Alexander Taylor managed to create XNAzymes, the XNA equivalent of a ribozyme, enzymes made of DNA or ribonucleic acid. This demonstrates that XNAs not only store hereditary information, but can also serve as enzymes, raising the possibility that life elsewhere could have begun with something other than RNA or DNA.

在特殊的聚合酶被开发出来之前，对XNA的研究并不多，这种酶能够以DNA为模板复制出XNA，也能将XNA复制回DNA。例如皮涅罗（Pinheiro）等人在2012年的一项研究已证明了一种可以在大约100bp序列长度上工作的XNA聚合酶。最近，合成生物学家菲利普·霍利格（Philipp Holliger）和亚历山大·泰勒（Alexander Taylor）成功地创造了XNAzymes。XNAzymes相当于核酶，由DNA或核糖核酸构成。这表明，这表明XNAs不仅存储遗传信息，还可以作为酶，这提高了其他地方的生命可能起源于RNA或DNA以外物质的可能性。

Structure 结构

This image displays the differences in the sugar backbones used in XNAs compared to common and biologically used DNA and RNA.

Strands of DNA and RNA are formed by stringing together long chains of molecules called nucleotides. A nucleotide is made up of three chemical components: a phosphate, a five-carbon sugar group (this can be either a deoxyribose sugar—which gives us the "D" in DNA—or a ribose sugar—the "R" in RNA), and one of five standard bases (adenine, guanine, cytosine, thymine or uracil).

thumb|369x369px|This image displays the differences in the sugar backbones used in XNAs compared to common and biologically used DNA and RNA. Strands of DNA and RNA are formed by stringing together long chains of molecules called nucleotides. A nucleotide is made up of three chemical components: a phosphate, a five-carbon sugar group (this can be either a deoxyribose sugar—which gives us the "D" in DNA—or a ribose sugar—the "R" in RNA), and one of five standard bases (adenine, guanine, cytosine, thymine or uracil).

这张图片显示了XNAs中使用的糖骨架与生物学中常见的DNA和RNA之间的差异。DNA链和RNA链是由名为核苷酸的长链分子串联而成的。核苷酸由三种化学成分组成：磷酸、五碳糖（可以是脱氧核糖，它给DNA提供了“D”，也可以是核糖，即RNA中的“R”) 、以及五种标准碱基之一（腺嘌呤、鸟嘌呤、胞嘧啶、胸腺嘧啶或尿嘧啶）。

The molecules that piece together to form the six xeno nucleic acids are almost identical to those of DNA and RNA, with one exception: in XNA nucleotides, the deoxyribose and ribose sugar groups of DNA and RNA have been replaced with other chemical structures. These substitutions make XNAs functionally and structurally analogous to DNA and RNA despite being unnatural and artificial.

The molecules that piece together to form the six xeno nucleic acids are almost identical to those of DNA and RNA, with one exception: in XNA nucleotides, the deoxyribose and ribose sugar groups of DNA and RNA have been replaced with other chemical structures. These substitutions make XNAs functionally and structurally analogous to DNA and RNA despite being unnatural and artificial.

组成这六种异源核酸的分子与DNA和RNA的分子几乎完全相同，只有一处例外：在XNA核苷酸中，DNA和RNA的脱氧核糖和核糖被其他化学结构所取代。这些替换使得XNAs功能和结构上与DNA和RNA相似，尽管它们是非自然的、人工的。

XNA exhibits a variety of structural chemical changes relative to its natural counterparts. Types of synthetic XNA created so far include:[2]

  • 1,5-anhydrohexitol nucleic acid (HNA)
  • Cyclohexene nucleic acid (CeNA)
  • Threose nucleic acid (TNA)
  • Glycol nucleic acid (GNA)
  • Locked nucleic acid ([1])
  • Peptide nucleic acid (PNA)
  • FANA (Fluoro Arabino nucleic acid)

XNA exhibits a variety of structural chemical changes relative to its natural counterparts. Types of synthetic XNA created so far include:

  • 1,5-anhydrohexitol nucleic acid (HNA)
  • Cyclohexene nucleic acid (CeNA)
  • Threose nucleic acid (TNA)
  • Glycol nucleic acid (GNA)
  • Locked nucleic acid ()
  • Peptide nucleic acid (PNA)
  • FANA (Fluoro Arabino nucleic acid)

XNA相对于DNA和RNA能表现出各种结构上的化学变化。迄今为止合成的XNA类型包括:

  • 1,5-脱水己醇核酸（HNA）
  • 环己烯核酸（CeNA）
  • 苏糖核酸（TNA）
  • 乙二醇核酸（GNA）
  • 锁核酸（LNA）
  • 肽核酸（PNA）
  • 2氟-阿拉伯糖核酸（FANA）

HNA could be used to potentially act as a drug that can recognize and bind to specified sequences. Scientists have been able to isolate HNAs for the possible binding of sequences that target HIV.[6] With cyclohexene nucleic acid, research has shown that CeNAs with stereochemistry similar to the D form can create stable duplexes with itself and RNA. It was shown that CeNAs are not as stable when they form duplexes with DNA.[7]

HNA could be used to potentially act as a drug that can recognize and bind to specified sequences. Scientists have been able to isolate HNAs for the possible binding of sequences that target HIV. With cyclohexene nucleic acid, research has shown that CeNAs with stereochemistry similar to the D form can create stable duplexes with itself and RNA. It was shown that CeNAs are not as stable when they form duplexes with DNA.

HNA可被用作识别和结合特定序列的药物。科学家已经能够分离出HNAs，以靶向结合艾滋病毒相关的基因序列。研究表明，在存在环己烯核酸的情况下，具有类似D型立体化学结构的CeNAs可以与自身和RNA形成稳定的双链体。结果表明，当CeNAs与DNA形成双链体时，CeNAs不是很稳定。

Implications启示

The study of XNA is not intended to give scientists a better understanding of biological evolution as it has occurred historically, but rather to explore ways in which we can control and even reprogram the genetic makeup of biological organisms moving forward. XNA has shown significant potential in solving the current issue of genetic pollution in genetically modified organisms.[8] While DNA is incredibly efficient in its ability to store genetic information and lend complex biological diversity, its four-letter genetic alphabet is relatively limited. Using a genetic code of six XNAs rather than the four naturally occurring DNA nucleotide bases yields endless opportunities for genetic modification and expansion of chemical functionality.[9]

The study of XNA is not intended to give scientists a better understanding of biological evolution as it has occurred historically, but rather to explore ways in which we can control and even reprogram the genetic makeup of biological organisms moving forward. XNA has shown significant potential in solving the current issue of genetic pollution in genetically modified organisms. While DNA is incredibly efficient in its ability to store genetic information and lend complex biological diversity, its four-letter genetic alphabet is relatively limited. Using a genetic code of six XNAs rather than the four naturally occurring DNA nucleotide bases yields endless opportunities for genetic modification and expansion of chemical functionality.

XNA研究的目的不是为了让科学家更好地了解历史上发生过的生物进化，而是探索我们能够控制甚至重新编程生物体基因组成的方法。XNA在解决目前转基因生物的遗传污染问题上显示出巨大潜力。尽管DNA在储存遗传信息和提供复杂生物多样性方面具有令人难以置信的效率，但其四个字母的遗传密码表相对有限。使用6个XNAs的遗传密码而不是4个自然产生的DNA碱基，或将展现出基因修饰和扩展化学功能的无尽机遇。

The development of various hypotheses and theories about XNAs have altered a key factor in our current understanding of nucleic acids: that heredity and evolution are not limited to DNA and RNA as once thought, but are simply processes that have developed from polymers capable of storing information.[4] Investigations into XNAs will allow for researchers to assess whether DNA and RNA are the most efficient and desirable building blocks of life, or if these two molecules were chosen randomly after evolving from a larger class of chemical ancestors.[10]

The development of various hypotheses and theories about XNAs have altered a key factor in our current understanding of nucleic acids: that heredity and evolution are not limited to DNA and RNA as once thought, but are simply processes that have developed from polymers capable of storing information. Investigations into XNAs will allow for researchers to assess whether DNA and RNA are the most efficient and desirable building blocks of life, or if these two molecules were chosen randomly after evolving from a larger class of chemical ancestors.

关于XNAs的各种假说和理论的发展已经改变了目前我们理解核酸的一个关键点: 遗传和进化并不是人们曾经认为的那样只局限于DNA和RNA，而仅仅是一种起源于能够储存信息的聚合物的简单过程。对于XNAs的研究将允许研究人员评估DNA和RNA是不是最有效和最理想的生命构件，或者这两种分子是不是在更大类的化学祖先进化之后被随机地选择出来的。

Applications

One theory of XNA utilization is its incorporation into medicine as a disease-fighting agent. Some enzymes and antibodies that are currently administered for various disease treatments are broken down too quickly in the stomach or bloodstream. Because XNA is foreign and because it is believed that humans have not yet evolved the enzymes to break them down, XNAs may be able to serve as a more durable counterpart to the DNA and RNA-based treatment methodologies that are currently in use.[11]

One theory of XNA utilization is its incorporation into medicine as a disease-fighting agent. Some enzymes and antibodies that are currently administered for various disease treatments are broken down too quickly in the stomach or bloodstream. Because XNA is foreign and because it is believed that humans have not yet evolved the enzymes to break them down, XNAs may be able to serve as a more durable counterpart to the DNA and RNA-based treatment methodologies that are currently in use.

= = 应用 = = 一种利用XNA的理论是将其作为抗病剂纳入医学。目前，一些用于各种疾病治疗的酶和抗体在胃或血液中分解得太快。但由于XNA是外来的，而且人类尚未进化出能够分解它们的酶，因此对于目前正在使用的DNA和RNA治疗方法，XNA可能成为比它们更持久的替换物。

Experiments with XNA have already allowed for the replacement and enlargement of this genetic alphabet, and XNAs have shown complementarity with DNA and RNA nucleotides, suggesting potential for its transcription and recombination. One experiment conducted at the University of Florida led to the production of an XNA aptamer by the AEGIS-SELEX (artificially expanded genetic information system - systematic evolution of ligands by exponential enrichment) method, followed by successful binding to a line of breast cancer cells.[12] Furthermore, experiments in the model bacterium E. coli have demonstrated the ability for XNA to serve as a biological template for DNA in vivo.[13]

Experiments with XNA have already allowed for the replacement and enlargement of this genetic alphabet, and XNAs have shown complementarity with DNA and RNA nucleotides, suggesting potential for its transcription and recombination. One experiment conducted at the University of Florida led to the production of an XNA aptamer by the AEGIS-SELEX (artificially expanded genetic information system - systematic evolution of ligands by exponential enrichment) method, followed by successful binding to a line of breast cancer cells. Furthermore, experiments in the model bacterium E. coli have demonstrated the ability for XNA to serve as a biological template for DNA in vivo.

XNA实验已经可以替换和扩大遗传密码表，而且XNA已经显示出与DNA和RNA核苷酸的互补性，这表明它具有转录和重组的潜力。在佛罗里达大学进行的一项实验中，通过AEISIS-SELEX（人工扩增的遗传信息系统——通过指数富集的配体的系统进化）产生了一种XNA适配体，并成功与乳腺癌细胞系结合。此外，在大肠杆菌中的实验表明，XNA在体内具有作为DNA生物模板的能力。

In moving forward with genetic research on XNAs, various questions must come into consideration regarding biosafety, biosecurity, ethics, and governance/regulation.[2] One of the key questions here is whether XNA in an in vivo setting would intermix with DNA and RNA in its natural environment, thereby rendering scientists unable to control or predict its implications in genetic mutation.[11]

In moving forward with genetic research on XNAs, various questions must come into consideration regarding biosafety, biosecurity, ethics, and governance/regulation. One of the key questions here is whether XNA in an in vivo setting would intermix with DNA and RNA in its natural environment, thereby rendering scientists unable to control or predict its implications in genetic mutation.

在推进对XNAs的基因研究时，必须考虑到有关生物安全、生物防护、伦理和治理/监管的各种问题。这里的一个关键问题是，在体内环境中，XNA是否会与自然环境中的DNA和RNA混合，从而使科学家无法控制或预测其在基因突变中可能的影响。

XNA also has potential applications to be used as catalysts, much like RNA has the ability to be used as an enzyme. Researchers have shown XNA is able to cleave and ligate DNA, RNA and other XNA sequences, with the most activity being XNA catalyzed reactions on XNA molecules. This research may be used in determining whether DNA and RNA's role in life emerged through natural selection processes or if it was simply a coincidental occurrence.[14]

XNA also has potential applications to be used as catalysts, much like RNA has the ability to be used as an enzyme. Researchers have shown XNA is able to cleave and ligate DNA, RNA and other XNA sequences, with the most activity being XNA catalyzed reactions on XNA molecules. This research may be used in determining whether DNA and RNA's role in life emerged through natural selection processes or if it was simply a coincidental occurrence.

XNA还可以作催化剂，就像RNA可以当作酶一样。研究人员已经证明，XNA能够剪切和连接DNA、RNA和其他XNA序列，其中XNA对XNA分子的催化反应最具活性。这项研究可以用来确定DNA和RNA在生命中的作用是通过自然选择过程产生的，还是说仅仅是一个巧合。

XNA may be employed as molecular clamps in quantitative real-time polymerase chain reactions (qPCR) by hybridizing with target DNA sequences.[15] In a study published in PLOS ONE, an XNA-mediated molecular clamping assay detected mutant cell-free DNA (cfDNA) from precancerous colorectal cancer (CRC) lesions and colorectal cancer.[15] XNA may also act as highly specific molecular probes for detection of nucleic acid target sequence.[16]

XNA may be employed as molecular clamps in quantitative real-time polymerase chain reactions (qPCR) by hybridizing with target DNA sequences. In a study published in PLOS ONE, an XNA-mediated molecular clamping assay detected mutant cell-free DNA (cfDNA) from precancerous colorectal cancer (CRC) lesions and colorectal cancer. XNA may also act as highly specific molecular probes for detection of nucleic acid target sequence.

XNA可以通过与靶DNA序列杂交，作为定量实时聚合酶链式反应（qPCR）的分子钳。在《公共科学图书馆》（PLOS ONE）期刊上发表的一项研究中，一种DNA介导的分子钳技术检测到了癌前结直肠癌 (CRC)病变和结直肠癌的突变无细胞DNA（cfDNA）。XNA还可以作为检测核酸靶序列的高特异性分子探针。

See also

  • Nucleic acid analogue
  • Xenobiology

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 核酸类似物 异源生物学

References

  1. ↑ Schmidt, Markus (2012). Synthetic Biology. John Wiley & Sons. pp. 151–. ISBN 978-3-527-65926-5. https://books.google.com/books?id=lr0SgX1Hx2gC&pg=PA151. 
  2. ↑ 2.0 2.1 2.2 Schmidt M (April 2010). "Xenobiology: a new form of life as the ultimate biosafety tool". BioEssays. 32 (4): 322–331. doi:10.1002/bies.200900147. PMC 2909387. PMID 20217844.
  3. ↑ 3.0 3.1 Gonzales R (19 April 2012). "XNA Is Synthetic DNA That's Stronger than the Real Thing". Io9. Retrieved 15 October 2015.
  4. ↑ 4.0 4.1 Pinheiro VB, Taylor AI, Cozens C, Abramov M, Renders M, Zhang S, et al. (April 2012). "Synthetic genetic polymers capable of heredity and evolution". Science. 336 (6079): 341–344. Bibcode:2012Sci...336..341P. doi:10.1126/science.1217622. PMC 3362463. PMID 22517858.
  5. ↑ "World's first artificial enzymes created using synthetic biology". Medical Research Council. 1 December 2014.
  6. ↑ Extance A (19 April 2012). "Polymers perform non-DNA evolution". Royal Society of Chemistry. Retrieved 15 October 2015.
  7. ↑ Gu P, Schepers G, Rozenski J, Van Aerschot A, Herdewijn P (2003). "Base pairing properties of D- and L-cyclohexene nucleic acids (CeNA)". Oligonucleotides. 13 (6): 479–489. doi:10.1089/154545703322860799. PMID 15025914.
  8. ↑ Herdewijn P, Marlière P (June 2009). "Toward safe genetically modified organisms through the chemical diversification of nucleic acids". Chemistry & Biodiversity. 6 (6): 791–808. doi:10.1002/cbdv.200900083. PMID 19554563. S2CID 8572188.
  9. ↑ Pinheiro VB, Holliger P (August 2012). "The XNA world: progress towards replication and evolution of synthetic genetic polymers". Current Opinion in Chemical Biology. 16 (3–4): 245–252. doi:10.1016/j.cbpa.2012.05.198. PMID 22704981.
  10. ↑ Hunter P (May 2013). "XNA marks the spot. What can we learn about the origins of life and the treatment of disease through artificial nucleic acids?". EMBO Reports. 14 (5): 410–413. doi:10.1038/embor.2013.42. PMC 3642382. PMID 23579343.
  11. ↑ 11.0 11.1 "XNA: Synthetic DNA That Can Evolve". Popular Mechanics. 19 April 2012. Retrieved 17 November 2015.
  12. ↑ Sefah K, Yang Z, Bradley KM, Hoshika S, Jiménez E, Zhang L, et al. (January 2014). "In vitro selection with artificial expanded genetic information systems". Proceedings of the National Academy of Sciences of the United States of America. 111 (4): 1449–1454. Bibcode:2014PNAS..111.1449S. doi:10.1073/pnas.1311778111. PMC 3910645. PMID 24379378.
  13. ↑ Pezo V, Liu FW, Abramov M, Froeyen M, Herdewijn P, Marlière P (July 2013). "Binary genetic cassettes for selecting XNA-templated DNA synthesis in vivo". Angewandte Chemie. 52 (31): 8139–8143. doi:10.1002/anie.201303288. PMID 23804524.
  14. ↑ Taylor AI, Pinheiro VB, Smola MJ, Morgunov AS, Peak-Chew S, Cozens C, et al. (February 2015). "Catalysts from synthetic genetic polymers". Nature. 518 (7539): 427–430. Bibcode:2015Natur.518..427T. doi:10.1038/nature13982. PMC 4336857. PMID 25470036.
  15. ↑ 15.0 15.1 Sun Q, Pastor L, Du J, Powell MJ, Zhang A, Bodmer W, et al. (5 October 2021). "A novel xenonucleic acid-mediated molecular clamping technology for early colorectal cancer screening". PLOS ONE. 16 (10): e0244332. Bibcode:2021PLoSO..1644332S. doi:10.1371/journal.pone.0244332. PMC 8491914. PMID 34610014.
  16. ↑ D'Agata R, Giuffrida MC, Spoto G (November 2017). "Peptide Nucleic Acid-Based Biosensors for Cancer Diagnosis". Molecules. 22 (11): 1951. doi:10.3390/molecules22111951. PMC 6150339. PMID 29137122.

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Category:Helices Category:Nucleic acids

类别: 螺旋体类别: 核酸


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