Crystal structure of Staphylococcus aureus peptidyl-tRNA hydrolase at a 2.25 Å resolution

Peptidyl-tRNA hydrolase (Pth) catalyzes the release of tRNA to relieve peptidyl-tRNA accumulation. Because Pth activity is essential for the viability of bacteria, Pth is regarded as a promising target for the discovery of new antimicrobial agents. Here, the structure of Pth from the Gram-positive bacterium Staphylococcus aureus (SaPth) was solved by X-ray crystallography at a 2.25 angstrom resolution. The SaPth structure exhibits significant structural similarity with other members of the Pth superfamily, with a conserved alpha/beta/alpha sandwich fold. A molecular phylogenetic analysis and a structure database search indicated that SaPth is most similar to its homolog in Streptococcus pyogenes, but it has a different substrate-binding cleft state.