title: Valyl-tRNA synthetase gene of Escherichia coli K12. Primary structure and homology within a family of aminoacyl-TRNA synthetases.
abstract: The DNA nucleotide sequence of the valS gene encoding valyl-tRNA synthetase of Escherichia coli has been determined. The deduced primary structure of valyl-tRNA synthetase was compared to the primary sequences of the known aminoacyl-tRNA synthetases of yeast and bacteria. Significant homology was detected between valyl-tRNA synthetase of E. coli and other known branched-chain aminoacyl-tRNA synthetases. In pairwise comparisons the highest level of homology was detected between the homologous valyl-tRNA synthetases of yeast and E. coli, with an observed 41% direct identity overall. Comparisons between the valyl- and isoleucyl-tRNA synthetases of E. coli yielded the highest level of homology detected between heterologous enzymes (19.2% direct identity overall). An alignment is presented between the three branched-chain aminoacyl-tRNA synthetases (valyl- and isoleucyl-tRNA synthetases of E. coli and yeast mitochondrial leucyl-tRNA synthetase) illustrating the close relatedness of these enzymes. These results give credence to the supposition that the branched-chain aminoacyl-tRNA synthetases along with methionyl-tRNA synthetase form a family of genes within the aminoacyl-tRNA synthetases that evolved from a common ancestral progenitor gene.
authors.affiliation: Department of Microbiology and Molecular Genetics, California College of Medicine, University of California, Irvine 92717.
authors.forename: J D
authors.initials: JD
authors.lastname: Heck
authors.forename: G W
authors.initials: GW
authors.lastname: Hatfield
mesh_terms: D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics*; D001483:Base Sequence; D003062:Codon; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D014637:Valine-tRNA Ligase / Q000235:genetics*
chemical_list: D003062:Codon; D000604:Amino Acyl-tRNA Synthetases; D014637:Valine-tRNA Ligase