Laboratoire de Réactivité de Surface, UMR 7197, Sorbonne Université, Case Courrier 178, 4 Pl. Jussieu, 75252, Paris CEDEX 05, France.
Laboratoire d'Archéologie Moléculaire et Structurale, UMR 8220, Sorbonne Université, Case Courrier 178, 4 Pl. Jussieu, 75252, Paris CEDEX 05, France.
Chemistry. 2019 Jan 24;25(5):1275-1285. doi: 10.1002/chem.201803845. Epub 2018 Dec 20.
Evidence for the formation of linear oligopeptides with nonrandom sequences from mixtures of amino acids coadsorbed on silica and submitted to a simple thermal activation is presented. The amino acid couples (glutamic acid+leucine) and (aspartic acid+valine) were deposited on a fumed silica and submitted to a single heating step at moderate temperature. The evolution of the systems was characterized by X-ray diffraction, infrared spectroscopy, thermosgravimetric analysis, HPLC, and electrospray ionization mass spectrometry (ESI-MS). Evidence for the formation of amide bonds was found in all systems studied. While the products of single amino acids activation on silica could be considered as evolutionary dead ends, (glutamic acid+leucine) and, at to some extent, (aspartic acid+valine) gave rise to the high yield formation of linear peptides up to the hexamers. Oligopeptides of such length have not been observed before in surface polymerization scenarios (unless the amino acids had been deposited by chemical vapor deposition, which is not realistic in a prebiotic environment). Furthermore, not all possible amino acid sequences were present in the activation products, which is indicative of polymerization selectivity. These results are promising for origins of life studies because they suggest the emergence of nonrandom biopolymers in a simple prebiotic scenario.
本文提出了一种证据，证明在氨基酸混合物共吸附于硅胶上并经简单热激活后，可形成具有非随机序列的线性寡肽。在实验中，将氨基酸对（谷氨酸+亮氨酸）和（天冬氨酸+缬氨酸）共沉积于无定形硅胶上，然后在中等温度下进行单一加热步骤。通过 X 射线衍射、红外光谱、热重分析、高效液相色谱和电喷雾电离质谱（ESI-MS）对体系的演化进行了表征。在所有研究的体系中都发现了形成酰胺键的证据。虽然在硅胶上激活单个氨基酸的产物可以被认为是进化的死胡同，但（谷氨酸+亮氨酸）和（天冬氨酸+缬氨酸）在一定程度上可以高产率地形成线性肽，直到六聚体。在表面聚合场景中，以前没有观察到这种长度的寡肽（除非氨基酸是通过化学气相沉积沉积的，而这在原始生命环境中是不现实的）。此外，在激活产物中并非存在所有可能的氨基酸序列，这表明聚合具有选择性。这些结果对于生命起源研究具有重要意义，因为它们表明在简单的原始生命场景中出现了非随机生物聚合物。
