In situ observation of peptide bond formation at the water-air interface
In situ observation of peptide bond formation at the water-air interface
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DOI：
10.1073/pnas.1210029109
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发表时间：
2012-09-25
影响因子：
11.1
通讯作者：
Vaida, Veronica
中科院分区：
文献类型：
--
作者：
Griffith, Elizabeth C.;Vaida, Veronica
我们报告明确的光谱证据的肽键形成在空气-水界面，产生一个可能的机制，提供洞察现代核糖体肽键的形成，并为早期地球上出现的肽的手段。在水环境中，通过连续氨基酸缩合形成肽来促进蛋白质合成，是现代生物学中普遍存在的过程，也是生命前化学中必需的基本反应。然而，这样的反应是缩合反应，对于形成的每个肽键，需要消除水分子，因此从热力学和动力学的观点来看，在水性环境中是不利的。我们使用的空气-水界面的疏水环境作为一个有利的场所，肽键合成，并证明这种化学的发生与原位技术，使用朗缪尔槽法和红外反射吸收光谱。亮氨酸乙酯（一种小的氨基酸酯）首先分配到水表面，然后在界面与Cu 2+离子配位，随后在空气-水界面进行缩合反应选择性地形成肽键。
We report unambiguous spectroscopic evidence of peptide bond formation at the air-water interface, yielding a possible mechanism providing insight into the formation of modern ribosomal peptide bonds, and a means for the emergence of peptides on early Earth. Protein synthesis in aqueous environments, facilitated by sequential amino acid condensation forming peptides, is a ubiquitous process in modern biology, and a fundamental reaction necessary in prebiotic chemistry. Such reactions, however, are condensation reactions, requiring the elimination of a water molecule for every peptide bond formed, and are thus unfavorable in aqueous environments both from a thermodynamic and kinetic point of view. We use the hydrophobic environment of the air-water interface as a favorable venue for peptide bond synthesis, and demonstrate the occurrence of this chemistry with in situ techniques using Langmuir-trough methods and infrared reflection absorption spectroscopy. Leucine ethyl ester (a small amino acid ester) first partitions to the water surface, then coordinates with Cu2+ ions at the interface, and subsequently undergoes a condensation reaction selectively forming peptide bonds at the air-water interface.