Primary Structure of a Large Aminoacyl-tRNA Synthetase

Abstract
The complete primary structure of Escherichia coli alanyl-tRNA synthetase, a 95,000-dalton polypeptide, was established by sequencing the gene encoding the enzyme and by sequencing oligopeptides in hydrolysates of the protein by gas chromatography-mass spectrometry. Contrary to expectation, this long polypeptide contains no lengthy duplications. One 13-residue peptide is homologous with E. coli tyrosyl-tRNA synthetase, and clusters of charged amino acids occur in several sections of the structure.