Anchoring of surface proteins to the cell wall of Staphylococcus aureus. Cysteine 184 and histidine 120 of sortase form a thiolate-imidazolium ion pair for catalysis.
نویسندگان
چکیده
Surface proteins of Staphylococcus aureus are anchored to the cell wall peptidoglycan by a mechanism requiring a C-terminal sorting signal with a LPXTG motif. Sortase cleaves polypeptides between the threonine and the glycine of the LPXTG motif. The carboxyl group of threonine is subsequently amide-linked to the amino group of peptidoglycan cross-bridges. The three-dimensional structure of sortase revealed the close proximity of the catalytic site residue cysteine 184 with histidine 120; however, no structural evidence for a thiolate-imidazolium ion pair could be detected. We report that alanine substitution of either cysteine 184 or histidine 120 abolishes in vivo and in vitro sorting reactions. Further, alanine substitution of tryptophan 194, a residue that is in close proximity of histidine 120, reduces the transpeptidase activity of sortase. These results suggest a model whereby sortase forms a thiolate-imidazolium ion pair for the catalysis of its transpeptidation reaction and that the position of tryptophan 194 assists in the formation of this ion pair.
منابع مشابه
Anchoring of Surface Proteins to the Cell Wall of Staphylococcus aureus II. CYSTEINE 184 AND HISTIDINE 120 OF SORTASE FORM A THIOLATE- IMIDAZOLIUM ION PAIR FOR CATALYSIS*
متن کامل
Sortase from Staphylococcus aureus does not contain a thiolate-imidazolium ion pair in its active site.
Many surface proteins are anchored to the cell wall by the action of sortase enzymes, a recently discovered family of cysteine transpeptidases. As the surface proteins of human pathogens are frequently required for virulence, the sortase-mediated anchoring reaction represents a potential target for new anti-infective agents. It has been suggested that the sortase from Staphylococcus aureus (Srt...
متن کاملStructure of sortase, the transpeptidase that anchors proteins to the cell wall of Staphylococcus aureus.
Surface proteins of Gram-positive bacteria play important roles during the pathogenesis of human infections and require sortase for anchoring to the cell-wall envelope. Sortase cleaves surface proteins at the LPXTG motif and catalyzes the formation of an amide bond between the carboxyl group of threonine (T) and the amino group of cell-wall crossbridges. The NMR structure of sortase reveals a u...
متن کاملAnchoring of surface proteins to the cell wall of Staphylococcus aureus. Sortase catalyzed in vitro transpeptidation reaction using LPXTG peptide and NH(2)-Gly(3) substrates.
Staphylococcus aureus sortase anchors surface proteins to the cell wall envelope by cleaving polypeptides at the LPXTG motif. Surface proteins are linked to the peptidoglycan by an amide bond between the C-terminal carboxyl and the amino group of the pentaglycine cross-bridge. We find that purified recombinant sortase hydrolyzed peptides bearing an LPXTG motif at the peptide bond between threon...
متن کاملPurification and characterization of sortase, the transpeptidase that cleaves surface proteins of Staphylococcus aureus at the LPXTG motif.
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 pepti...
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عنوان ژورنال:
- The Journal of biological chemistry
دوره 277 9 شماره
صفحات -
تاریخ انتشار 2002