Showing papers by "Sarkis K. Mazmanian published in 1999"

Staphylococcus aureus Sortase, an Enzyme that Anchors Surface Proteins to the Cell Wall

Abstract: Surface proteins of Gram-positive bacteria are linked to the bacterial cell wall by a mechanism that involves cleavage of a conserved Leu-Pro-X-Thr-Gly (LPXTG) motif and that occurs during assembly of the peptidoglycan cell wall A Staphylococcus aureus mutant defective in the anchoring of surface proteins was isolated and shown to carry a mutation in the srtA gene Overexpression of srtA increased the rate of surface protein anchoring, and homologs of srtA were found in other pathogenic Gram-positive bacteria The protein specified by srtA, sortase, may be a useful target for the development of new antimicrobial drugs

Purification and characterization of sortase, the transpeptidase that cleaves surface proteins of Staphylococcus aureus at the LPXTG motif

Abstract: Surface proteins of Staphylococcus aureus are linked to the bacterial cell wall by sortase, an enzyme that cleaves polypeptides at the threonine of the LPXTG motif. Surface proteins can be released from staphylococci by treatment with hydroxylamine, resulting in the formation of threonine hydroxamate. Staphylococcal extracts, as well as purified sortase, catalyze the hydroxylaminolysis of peptides bearing an LPXTG motif, a reaction that can be inhibited with sulfhydryl-modifying reagents. Replacement of the single conserved cysteine at position 184 of sortase with alanine abolishes enzyme activity. Thus, sortase appears to catalyze surface-protein anchoring by means of a transpeptidation reaction that captures cleaved polypeptides as thioester enzyme intermediates.