| The origin of proteins: Heteropolypeptides from hydrogen cyanide and water. | |
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MedLine Citation:
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PMID: 168535 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Evidence from laboratory and extraterrestrial chemistry is presented consistent with the hypothesis that the original heteropolypeptides on Earth were synthesized spontaneously from hydrogen cyanide and water without the intervening formation of chi-amino acids, a key step being the direct polymerization of atmospheric hydrogen cyanide to polyaminomalononitrile (IV) via dimeric HCN. Molecular orbital calculations (INDO) show that the most probable structure for (HCN)2 is azacyclopropenylidenimine. Successive reactions of hydrogen cyanide with the reactive nitrile side chains of IV then yield heteropolyamidines which are converted by water to heteropolypeptides. To study this postulated modification of a homopolymer to a heteropolymer, poly-chi-cyanoglycine (IX) was prepared from the N-carboxyanhydride of chi-cyanoglycine. Hydrolysis of IX, a polyamide analog of the polyamidine IV, yielded glycine. However, when IX was hydrolysed after being treated with hydrogen cyanide, other chi-amino acids were also obtained including alanine, serine, aspartic acid and glutamic acid, suggesting that the nitrile groups of IX (and therfore of IV) are indeed readily attacked by hydrogen cyanide as predicted. Further theoretical and experimental studies support the view that hydrogen cyanide polymerization along these lines is a universal process that accounts not only for the past formation of primitive proteins on Earth, but also for the yellow-brown-orange colors of Jupiter today and for the presence of water-soluble compounds hydrolyzable to chi-amino acids in materials obtained from environments as diverse as the moon, carbonaceous chondrites and the reaction chambers used to simulate organic synthesis in planetary atmospheres. |
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Authors:
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C N Matthews |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Origins of life Volume: 6 ISSN: 0302-1688 ISO Abbreviation: Orig. Life Publication Date: 1975 Jan-Apr |
Date Detail:
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Created Date: 1975-11-01 Completed Date: 1975-11-01 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0420542 Medline TA: Orig Life Country: NETHERLANDS |
Other Details:
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Languages: eng Pagination: 155-62 Citation Subset: IM; S |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acids
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chemical synthesis Atmosphere Biopolymers Geological Phenomena Geology Hydrogen Cyanide* Hydrolysis Nitriles / chemical synthesis Peptides / chemical synthesis* Water* |
| Chemical | |
Reg. No./Substance:
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0/Amino Acids; 0/Biopolymers; 0/Nitriles; 0/Peptides; 74-90-8/Hydrogen Cyanide; 7732-18-5/Water |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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