Structure of the yeast valyl-tRNA synthetase gene (VASI) and the homology of its translated amino acid sequence with Escherichia coli isoleucyl-tRNA synthetase

J Biol Chem. 1987 May 25;262(15):7189-94.

Abstract

The VASI gene encoding the valyl-tRNA synthetase from yeast was isolated and sequenced. The gene-derived amino acid sequence of yeast valyl-tRNA synthetase was found to be 23% homologous to the Escherichia coli isoleucyl-tRNA synthetase. This is the highest level of homology reported so far between two distinct aminoacyl-tRNA synthetases and is indicative of an evolutionary relationship between these two molecules. Within these homologous sequences, two functional regions could be recognized: the HIGH region which forms part of the binding site of ATP and the KMSKS region which is recognized as the consensus sequence for the binding of the 3'-end of tRNA (Hountondji, C., Dessen, Ph., and Blanquet, S. (1986) Biochemie (Paris) 68, 1071-1078). Secondary structure predictions as well as the presence of both HIGH and KMSKS regions, delineating the nucleotide-binding domain and the COOH-terminal helical domain in aminoacyl-tRNA synthetases of known three-dimensional structure, suggest that the yeast valyl-tRNA synthetase polypeptide chain can be folded into three domains: an NH2-terminal alpha-helical region followed by a nucleotide-binding topology and a COOH-terminal domain composed of alpha-helices which probably carries major sites in tRNA binding.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Amino Acid Sequence
  • Amino Acyl-tRNA Synthetases* / genetics*
  • Base Sequence
  • Binding Sites
  • Biological Evolution
  • Cloning, Molecular
  • DNA, Fungal / genetics
  • Escherichia coli / enzymology*
  • Isoleucine-tRNA Ligase*
  • Protein Conformation
  • RNA, Transfer / metabolism
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Sequence Homology, Nucleic Acid
  • Valine-tRNA Ligase / genetics*

Substances

  • DNA, Fungal
  • Adenosine Triphosphate
  • RNA, Transfer
  • Amino Acyl-tRNA Synthetases
  • Isoleucine-tRNA Ligase
  • Valine-tRNA Ligase

Associated data

  • GENBANK/J02719