Methionyl-tRNA synthetase from Escherichia coli: primary structure at the binding site for the 3'-end of tRNAfMet.
It was previously shown that when the tryptic fragment of methionyl-tRNA synthetase from Escherichia coli is incubated with periodate-treated initiator tRNA, it is inactivated due to the formation of a covalent 1:1 complex that could be stabilized by reduction with cyanoborohydride [Hountondji, C., Fayat, G., & Blanquet, S. (1979) Eur. J. Biochem. 102, 247-250]. In this work, the residues labeled in the trypsin-modified enzyme have been identified. After chymotryptic digestion of the protein-tRNA complex, two major labeled peptides (A and B) and a minor one (C) were isolated and identified by sequencing. The radioactivity associated with peptides A-C represented 65-75, 20-25, and 2-4%, respectively, of the radioactivity eluted from the peptide maps. Peptides A and B encompassed lysines-335 and -61, respectively. Both these lysines were fully labeled. Peptide C encompassed lysines-142, -147, and -149, each of which was incompletely labeled. The significance of these results is discussed in light of the known crystallographic structure of the enzyme.
D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D001665:Binding Sites; D002918:Chymotrypsin; D004926:Escherichia coli / Q000201:enzymology*; D008718:Methionine-tRNA Ligase / Q000378:metabolism*; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D012358:RNA, Transfer, Met; D014357:Trypsin
D010446:Peptide Fragments; D012346:RNA, Transfer, Amino Acyl; D012358:RNA, Transfer, Met; C024988:tRNA, formylmethionine-; D002918:Chymotrypsin; D014357:Trypsin; D000604:Amino Acyl-tRNA Synthetases; D008718:Methionine-tRNA Ligase