Department of Chemical Informatics, Faculty of Education, University of Szeged, Boldogasszony sgt. 6, Szeged 6725, Hungary.
Phys Chem Chem Phys. 2011 Apr 28;13(16):7449-58. doi: 10.1039/c0cp02687e. Epub 2011 Mar 22.
It has always been a question of considerable scientific interest why amino acids (and other biomolecule building blocks) formed and accumulated in the prebiotic ocean. In this study, we suggest an answer to this question for the simplest amino acid, glycine. We have shown for the first time that classical equilibrium thermodynamics can explain the most likely selection of glycine (and the derivative of its dipeptide) in aqueous media, although glycine is not the lowest free energy structure among all (404) possible constitutional isomers. Species preceding glycine in the free energy order are either supramolecular complexes of small molecules or such molecules likely to dissociate and thus get back to the gas phase. Then, 2-hydroxyacetamide condensates yielding a thermodynamically favored derivative of glycine dipeptide providing an alternative way for peptide formation. It is remarkable that a simple equilibrium thermodynamic model can explain the accumulation of glycine and provide a reason for the importance of water in the formation process.
为什么氨基酸（和其他生物分子构建块）在原始海洋中形成和积累，这一直是一个具有相当科学意义的问题。在这项研究中，我们为最简单的氨基酸甘氨酸回答了这个问题。我们首次表明，经典平衡热力学可以解释甘氨酸（及其二肽衍生物）在水介质中最有可能的选择，尽管甘氨酸不是所有（404）可能的构象异构体中自由能最低的结构。在自由能顺序中先于甘氨酸的物质，要么是小分子的超分子复合物，要么是可能解离并因此回到气相的分子。然后，2-羟基乙酰胺缩合生成甘氨酸二肽的热力学有利衍生物，为肽形成提供了另一种途径。值得注意的是，简单的平衡热力学模型可以解释甘氨酸的积累，并为水在形成过程中的重要性提供了一个理由。
