Origin of homochirality in terrestrial biology.

Abstract

Recent analysis of samples from asteroids Ryugu and Bennu did not reveal any significant amino acid enantiomeric excesses, and these facts appear to contradict the most prevailing view that a slight enantiomeric excess of L-amino acids present on the primitive Earth is the origin of homochirality. From the perspective of continuity in biological evolution, it would again be considered a strong possibility that primordial tRNA aminoacylation could have led to preferential homochiral (L-) protein biosynthesis on the early Earth (Tamura- Schimmel model), and that RNA played a major role in the generation of amino acid homochirality. The results of recent molecular dynamics simulations have also clarified the mechanism of its chiral selectivity.