Int. J. Mol. Sci. 2011, 12(7), 4745-4757; doi:10.3390/ijms12074745
Review

Molecular Basis for Chiral Selection in RNA Aminoacylation

1,2,3email
Received: 24 May 2011; in revised form: 29 June 2011 / Accepted: 18 July 2011 / Published: 22 July 2011
(This article belongs to the Special Issue Origin of Life 2011)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: The chiral-selective aminoacylation of an RNA minihelix is a potential progenitor to modern tRNA-based protein synthesis using l-amino acids. This article describes the molecular basis for this chiral selection. The extended double helical form of an RNA minihelix with a CCA triplet (acceptor of an amino acid), an aminoacyl phosphate donor nucleotide (mimic of aminoacyl-AMP), and a bridging nucleotide facilitates chiral-selective aminoacylation. Energetically, the reaction is characterized by a downhill reaction wherein an amino acid migrates from a high-energy acyl phosphate linkage to a lower-energy carboxyl ester linkage. The reaction occurs under the restriction that the nucleophilic attack of O, from 3′-OH in the terminal CCA, to C, from C=O in the acyl phosphate linkage, must occur at a Bürgi-Dunitz angle, which is defined as the O–C=O angle of approximately 105°. The extended double helical form results in a steric hindrance at the side chain of the amino acid leading to chiral preference combined with cation coordinations in the amino acid and the phosphate oxygen. Such a system could have developed into the protein biosynthetic system with an exclusively chiral component (l-amino acids) via (proto) ribosomes.
Keywords: homochirality; amino acid; RNA; aminoacylation; stereochemistry; extended double helix; origin of life
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MDPI and ACS Style

Tamura, K. Molecular Basis for Chiral Selection in RNA Aminoacylation. Int. J. Mol. Sci. 2011, 12, 4745-4757.

AMA Style

Tamura K. Molecular Basis for Chiral Selection in RNA Aminoacylation. International Journal of Molecular Sciences. 2011; 12(7):4745-4757.

Chicago/Turabian Style

Tamura, Koji. 2011. "Molecular Basis for Chiral Selection in RNA Aminoacylation." Int. J. Mol. Sci. 12, no. 7: 4745-4757.

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