Structural basis for anticodon recognition by methionyl-tRNA synthetase

In the 2.7-angstrom resolution crystal structure of methionyl-tRNA synthetase (MetRS) in complex with tRNA(Met) and a methionyladenylate analog, the tRNA anticodon loop is distorted to form a triple-base stack comprising C34, A35 and A38. A tryptophan residue stacks on C34 to extend the triple-base stack. In addition, C34 forms Watson-Crick-type hydrogen bonds with Arg357. This structure resolves the longstanding question of how MetRS specifically recognizes tRNA(Met).