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Publication Abstract from PubMed

Sortases function as cysteine transpeptidases that catalyze the covalent attachment of virulence-associated surface proteins into the cell wall peptidoglycan in Gram-positive bacteria. The substrate proteins targeted by sortase enzymes have a cell wall sorting signal (CWSS) located at the C-terminus. Up to date, it is still not well understood how sortases with structural resemblance among different classes and diverse species of bacteria achieve substrate specificity. In this study, we focus on elucidating the molecular basis for specific recognition of peptide substrate PPKTG by Clostridium difficile sortase B (Cd-SrtB). Combining structural studies, biochemical assays and molecular dynamics simulations, we have constructed a computational model of Cd-SrtBDeltaN26-PPKTG complex and have validated the model by site-directed mutagensis studies and fluorescence resonance energy transfer (FRET)-based assay. Furthermore, we have revealed that the fourth amino acid in the N-terminal direction from cleavage site of PPKTG forms specific interaction with Cd-SrtB and plays an essential role in configuring the peptide to allow more efficient substrate-specific cleavage by Cd-SrtB.

Structural Insights into Substrate Recognition by Clostridium difficile Sortase.,Yin JC, Fei CH, Lo YC, Hsiao YY, Chang JC, Nix JC, Chang YY, Yang LW, Huang IH, Wang S Front Cell Infect Microbiol. 2016 Nov 22;6:160. eCollection 2016. PMID:27921010^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.