Forsythe Jay G, Yu Sheng-Sheng, Mamajanov Irena, Grover Martha A, Krishnamurthy Ramanarayanan, Fernández Facundo M, Hud Nicholas V
NSF/NASA Center for Chemical Evolution (USA).
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA (USA).
Angew Chem Int Ed Engl. 2015 Aug 17;54(34):9871-5. doi: 10.1002/anie.201503792. Epub 2015 Jul 15.
Although it is generally accepted that amino acids were present on the prebiotic Earth, the mechanism by which α-amino acids were condensed into polypeptides before the emergence of enzymes remains unsolved. Here, we demonstrate a prebiotically plausible mechanism for peptide (amide) bond formation that is enabled by α-hydroxy acids, which were likely present along with amino acids on the early Earth. Together, α-hydroxy acids and α-amino acids form depsipeptides-oligomers with a combination of ester and amide linkages-in model prebiotic reactions that are driven by wet-cool/dry-hot cycles. Through a combination of ester-amide bond exchange and ester bond hydrolysis, depsipeptides are enriched with amino acids over time. These results support a long-standing hypothesis that peptides might have arisen from ester-based precursors.
尽管人们普遍认为氨基酸在生命起源前的地球上就已存在，但在酶出现之前α-氨基酸缩合形成多肽的机制仍未得到解决。在这里，我们展示了一种由α-羟基酸促成的、在生命起源前可能存在的肽（酰胺）键形成机制，早期地球上α-羟基酸可能与氨基酸同时存在。在由湿冷/干热循环驱动的模拟生命起源前反应中，α-羟基酸和α-氨基酸共同形成了具有酯键和酰胺键组合的缩肽低聚物。随着时间的推移，通过酯-酰胺键交换和酯键水解的组合，缩肽中氨基酸逐渐富集。这些结果支持了一个长期存在的假说，即肽可能起源于基于酯的前体。
