Han DaXiong, Chen WeiZhu, Han Bo, Zhao YuFen
Department of Pharmacy, Medical College of Xiamen University, Xiamen 361005, China.
Sci China C Life Sci. 2007 Oct;50(5):580-6. doi: 10.1007/s11427-007-0087-0.
Amino acid homochirality, as a unique behavior of life, could have originated synchronously with the genetic code. In this paper, phosphoryl amino-acid-5'-nucleosides with P-N bond are postulated to be a chiral origin model in prebiotic molecular evolution. The enthalpy change in the intramolecular interaction between the nucleotide base and the amino-acid side-chain determines the stability of the particular complex, resulting in a preferred conformation associated with the chirality of amino acids. Based on the theoretical model, our experiments and calculations show that the chiral selection of the earliest amino acids for L-enantiomers seems to be a strict stereochemical/physicochemical determinism. As other amino acids developed biosynthetically from the earliest amino acids, we infer that the chirality of the later amino acids was inherited from the precursor amino acids. This idea probably goes far back in history, but it is hoped that it will be a guide for further experiments in this area.
氨基酸同手性作为生命的一种独特行为，可能与遗传密码同步起源。本文提出，具有P-N键的磷酰化氨基酸-5'-核苷是前生物分子进化中的一种手性起源模型。核苷酸碱基与氨基酸侧链之间分子内相互作用的焓变决定了特定复合物的稳定性，从而产生与氨基酸手性相关的优选构象。基于该理论模型，我们的实验和计算表明，最早的氨基酸对L-对映体的手性选择似乎是一种严格的立体化学/物理化学决定论。由于其他氨基酸是从最早的氨基酸生物合成而来的，我们推断后来氨基酸的手性是从前体氨基酸继承而来的。这个想法可能历史悠久，但希望它能为该领域的进一步实验提供指导。
