National Center for
4QT4: Crystal Structure Of Peptidyl-trna Hydrolase From A Gram-positive Bacterium, Streptococcus Pyogenes At 2.19 Angstrom Resolution Shows The Closed Structure Of The Substrate Binding Cleft
Crystal structure of peptidyl-tRNA hydrolase from a Gram-positive bacterium, Streptococcus pyogenes at 2.19 Å resolution shows the closed structure of the substrate-binding cleft
FEBS Open Bio (2014) 4 p.915-922
Peptidyl-tRNA hydrolase (Pth) catalyses the release of tRNA and peptide components from peptidyl-tRNA molecules. Pth from a Gram-positive bacterium Streptococcus pyogenes (SpPth) was cloned, expressed, purified and crystallised. Three-dimensional structure of SpPth was determined by X-ray crystallography at 2.19 A resolution. Structure determination showed that the asymmetric unit of the unit cell contained two crystallographically independent molecules, designated A and B. The superimposition of C(alpha) traces of molecules A and B showed an r.m.s. shift of 0.4 A, indicating that the structures of two crystallographically independent molecules were identical. The polypeptide chain of SpPth adopted an overall alpha/beta conformation. The substrate-binding cleft in SpPth is formed with three loops: the gate loop, Ile91-Leu102; the base loop, Gly108-Gly115; and the lid loop, Gly136-Gly150. Unlike in the structures of Pth from Gram-negative bacteria, the entry to the cleft in the structure of SpPth appeared to be virtually closed. However, the conformations of the active site residues were found to be similar.