A new theoretical model for the origin of amino acid homochirality  

作　　者：HAN DaXiong1, CHEN WeiZhu2, HAN Bo2 & ZHAO YuFen1,2 1 Department of Pharmacy, Medical College of Xiamen University, Xiamen 361005, China 2 Department of Chemistry, Xiamen University, Xiamen 361005, China 

出　　处：《Science China(Life Sciences)》2007年第5期580-586,共7页中国科学（生命科学英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 20572061);the Science Foundation of Xiamen University (Grant No. Z03120)

摘　　要：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 sta-bility 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 stereochemi-cal/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 ex-periments in this area.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 sta-bility 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 stereochemi-cal/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 ex-periments in this area.

关 键 词：GENETIC code  phosphate  ORIGIN of life  CHIRAL selection  HOMOCHIRALITY 

分 类 号：Q517[生物学—生物化学]