Is required not only for elongation of protein synthesis but also for the initiation of all mRNA translation through initiator tRNA(fMet) aminoacylation. ATP + L-methionine + tRNA(Met) = AMP + diphosphate + L-methionyl-tRNA(Met) kcat is 2.83 sec(-1) with E.coli tRNAfMet as substrate. Monomer. Lacks the Zn(2+) binding motif and the C-terminal dimerization appendix that are found in MetRSs from several organisms including E.coli MetRS. Belongs to the class-I aminoacyl-tRNA synthetase family. MetG type 2B subfamily.