Crystal structures of apo wild-type M. jannaschii tyrosyl-tRNA synthetase (TyrRS) and an engineered TyrRS specific for O-methyl-L-tyrosine.

ABSTRACT: The Methanococcus jannaschii tRNA(Tyr)/TyrRS pair has been engineered to incorporate unnatural amino acids into proteins in E. coli. To reveal the structural basis for the altered specificity of mutant TyrRS for O-methyl-L-tyrosine (OMeTyr), the crystal structures for the apo wild-type and mutant M. jannaschii TyrRS were determined at 2.66 and 3.0 A, respectively, for comparison with the published structure of TyrRS complexed with tRNA(Tyr) and substrate tyrosine. A large conformational change was found for the anticodon recognition loop 257-263 of wild-type TyrRS upon tRNA binding in order to facilitate recognition of G34 of the anticodon loop through pi-stacking and hydrogen bonding interactions. Loop 133-143, which is close to the tRNA acceptor stem-binding site, also appears to be stab

SUBMITTER: Zhang Y 

PROVIDER: S-EPMC2253270 | biostudies-literature | 2005 May

REPOSITORIES: biostudies-literature