A new theoretical model for the origin of amino acid homochirality.
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.
Han
DaXiong
D
Department of Pharmacy, Medical College of Xiamen University, Xiamen 361005, China. daxiong@xmu.edu.cn
Chen
WeiZhu
W
Han
Bo
B
Zhao
YuFen
Y
D000596:Amino Acids / Q000737:chemistry*; D002627:Chemistry, Physical / Q000379:methods; D004247:DNA / Q000737:chemistry; D005815:Genetic Code; D008956:Models, Chemical; D008958:Models, Molecular; D008962:Models, Theoretical; D008968:Molecular Conformation; D009690:Nucleic Acid Conformation; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D013237:Stereoisomerism
D000596:Amino Acids; D011506:Proteins; D004247:DNA