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Genomics II: Bacteria, Viruses and Metabolic Pathways
Title
Genomics II: Bacteria, Viruses and Metabolic Pathways
Editor
iConcept Press
Price
USD$139.00
ISBN
978-1-480254-145
Clicks
22874

Chapter 9

Genomics II: Bacteria, Viruses and Metabolic Pathways

The Molecular Basis for Unilateral Aminoa-cylation Specificity between Mitochondria and Bacteria

by Sarin Chimnaronk, Yoshitaka Bessho and Kimitsuna Watanabe

Viewed: 1638

Abstract

Vertebrate mitochondrial (mt) aminoacyl-tRNA synthetases are able to aminoacylate both mt and bacterial cognate tRNAs, but bacterial synthetases aminoacylate only bacterial cognate tRNAs, at least with respect to synthetases for Phe, Thr, Arg, Lys, Ser and Asp. This phenomenon was named unilateral aminoacylation specificity between mitochondria and bacteria. Comparison of amino acid sequences of these synthetases from bovine mitochondria with those from Escherichia coli and Thermus thermophilus revealed that many regions in the sequences are very similar, except for some extra domains which are found only in mt synthetases. As an example of mt synthetases, bovine mt seryl-tRNA synthetases (SerRS) was analyzed by X-ray crystallography. The tertiary structure was almost identical with that of T. thermophilus which had been already analyzed, except for three extra domains at the N-terminal, between the two alpha-herical domains and at the C-terminal existing in bovine mt synthetase. It was revealed that the N-terminal helix (distal helix) and C-terminal tail (C-tail) were prerequisite for the recognition of mt serine tRNAs by mt SerRS. From this finding, together with the results obtained from comparison of E. coli tRNAs for Phe, Thr, Arg, Lys, Ser and Asp with the corresponding bovine mt counterparts with regard to secondary structures including identity determinants, it is most appropriate to presume that the unilateral aminoacylation specificity is caused by the extra domains existing only in mt aminoacyl-tRNA synthetases, but not by tRNA. Discussion will be made as to how and why such extra domains would have emerged in mt synthetases during the course of mt evolution.

Author Details

Sarin Chimnaronk
Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Thailand
Yoshitaka Bessho
RIKEN Spring-8 Center, Harima Institute, Japan, Japan
Kimitsuna Watanabe
Department of Molecular Biology, School of Life Sciences / Department of Biotechnology, Graduate School of Agricultural and Life Sciences, Tokyo University of Pharmacy and Life Sciences, Japan / University of Tokyo, Japan, Japan

Citation

Sarin Chimnaronk, Yoshitaka Bessho and Kimitsuna Watanabe. The Molecular Basis for Unilateral Aminoa-cylation Specificity between Mitochondria and Bacteria. In Genomics II: Bacteria, Viruses and Metabolic Pathways. ISBN:978-1-480254-145. iConcept Press. 0000.

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