Amino Acid Homochirality may be Linked to the Origin of Phosphate-Based Life
- 247 Downloads
Phosphorylation has to have been one of the key events in prebiotic evolution on earth. In this article, the emergence of phosphoryl amino acid 5′-nucleosides having a P–N bond is described as a model of the origin of amino acid homochirality and Genetic Code. It is proposed that the intramolecular interaction between the nucleotide base and the amino acid side-chain influences the stability of particular amino acid 5′-nucleotides, and the interaction also selects for the chirality of amino acids. The differences between l- and d-conformation energies (ΔEconf) are evaluated by DFT methods at the B3LYP/6-31G(d) level. Although, as expected, these ΔEconf values are not large, they do give differences in energy that can distinguish the chirality of amino acids. Based on our calculations, the chiral selection of the earliest amino acids for l-enantiomers seems to be determined by a clear stereochemical/physicochemical relationship. As later amino acids developed from the earliest amino acids, we deduce that the chirality of these late amino acids was inherited from that of the early amino acids. This idea reaches far back into evolution, and we hope that it will guide further experiments in this area.
KeywordsHomochirality Genetic codes Phosphate Origin of life Chiral selection
We thank Professor G. Michael Blackburn for useful discussions. This study was supported by the National Science Foundation of China (Grant No. 40976050 and Grant No. 40706043) and the 908 Project Foundation of State Oceanic Administration of China (FJ 908-02-03-05).
- Bailey JM (1998) RNA-directed amino acid homochirality. FASEB J 12:503–507Google Scholar
- Bailey J (2007) The inner solar system cataclysm, the origin of life, and the return to the moon. In: Proceedings of 6th Australian space science conference, Canberra, July 2006, pp 17–22Google Scholar
- Inous H, Baba Y, Furukawa T, Maeda Y, Tsuhako M (1993) Formation of dipeptide in the reaction of amino acids with cyclo-triphosphate. Chem Parm Bull 41:1895–1899Google Scholar
- Lin CX, Fu H, Tu GZ, Zhao YF (2003) Synthesis and chiral separation of dinucleotides(TpAZT) phosphoramidates. Chin Chem Lett 14:779–782Google Scholar
- Tan B, Lee MC, Cui M, Liu T, Chen ZZ, Li YM, Ju Y, Zhao YF, Chen KX, Jiang HL (2004) A common intermediate for prebiotic synthesis of proteins and nucleosides: a density functional theory (DFT) study on the formation from N-phosphoryl amino acids. J Mol Struct (Themchem) 672:51–60CrossRefGoogle Scholar