伦敦大学学院的Matthew W. Powner研究组在生命起源化学研究中取得进展，他们发现在中性水环境中利用前生命化学合成半胱氨酸肽并催化肽键形成是可能的。 该研究于2020年11月13日发表于《科学》。

在这篇研究中，团队报道了一种高产率合成半胱氨酸肽的前生命化学合成方法。他们的仿生合成路线通过腈活化的脱氢丙氨酸合成，将丝氨酸转化为半胱氨酸。研究人员还展示了N-乙酰半胱氨酸催化的肽键形成，即直接将动力学稳定但高能的α-氨基腈与蛋白质源的氨偶合。这一罕见的水中发生的高效选择性有机催化反应意味着半胱氨酸既可以在肽的前生命化学合成中充当前体，也可以作为催化剂。

据介绍，多肽的生物合成是通过核糖体和其他几种酶完成的，但生命起源之初的一批多肽可能是通过一些简单的化学反应合成的。前生命起源的α-氨基酸的前体——α-氨基腈通常是通过Strecker反应合成的。然而，半胱氨酸的巯基氨基酸结构与腈类化合物不兼容。因此，半胱氨酸腈是不稳定的，这使得人们过去认为半胱氨酸是进化的产物，而不是来自前生命起源的化学反应。

附：英文原文

Title: Prebiotic synthesis of cysteine peptides that catalyze peptide ligation in neutral water

Author: Callum S. Foden, Saidul Islam, Christian Fernández-García, Leonardo Maugeri, Tom D. Sheppard, Matthew W. Powner

Issue&Volume: 2020/11/13

Abstract: Peptide biosynthesis is performed by ribosomes and several other classes of enzymes, but a simple chemical synthesis may have created the first peptides at the origins of life. α-Aminonitriles—prebiotic α–amino acid precursors—are generally produced by Strecker reactions. However, cysteine’s aminothiol is incompatible with nitriles. Consequently, cysteine nitrile is not stable, and cysteine has been proposed to be a product of evolution, not prebiotic chemistry. We now report a high-yielding, prebiotic synthesis of cysteine peptides. Our biomimetic pathway converts serine to cysteine by nitrile-activated dehydroalanine synthesis. We also demonstrate that N-acylcysteines catalyze peptide ligation, directly coupling kinetically stable—but energy-rich—α-amidonitriles to proteinogenic amines. This rare example of selective and efficient organocatalysis in water implicates cysteine as both catalyst and precursor in prebiotic peptide synthesis.

DOI: 10.1126/science.abd5680

Source: https://science.sciencemag.org/content/370/6518/865