title: The aminoacylation of transfer ribonucleic acid. Recognition of methionine by Escherichia coli methionyl-transfer ribonucleic acid synthetase.
abstract: The mechanism of the recognition of methionine by Escherichia coli methionyl-tRNA synthetase was examined by a kinetic study of the recognition of methionine analogues in the ATP-PPi exchange reaction and the tRNA-aminoacylation reaction. The results show that the recognition mechanism consists of three parts: (1) the recognition of the size, shape and chemical nature of the amino acid side chain at the methionine-binding stage of the reaction; (2) the recognition of the length of the side chain at the stage of aminoacyl-adenylate complex-formation; (3) the recognition of the sulphur atom in the side chain at the stage of methionyl-tRNA formation. It is proposed that the sulphur atom interacts with the enzyme to induce a conformational change. A model of the active site incorporating the mechanism of methionine recognition is presented.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D008715:Methionine / Q000031:analogs & derivatives / Q000378:metabolism*; D008718:Methionine-tRNA Ligase / Q000378:metabolism*; D011487:Protein Conformation; D012343:RNA, Transfer / Q000378:metabolism*
chemical_list: D000255:Adenosine Triphosphate; D012343:RNA, Transfer; D008715:Methionine; D000604:Amino Acyl-tRNA Synthetases; D008718:Methionine-tRNA Ligase