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

Proc Natl Acad Sci U S A. 1999 Oct 26;96(22):12424-9. doi: 10.1073/pnas.96.22.12424.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Aminoacyltransferases / chemistry
  • Aminoacyltransferases / isolation & purification*
  • Aminoacyltransferases / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Catalysis
  • Cysteine / metabolism
  • Cysteine Endopeptidases
  • DNA Primers
  • Hydrolysis
  • Hydroxylamine / metabolism
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism*
  • Molecular Sequence Data
  • Sequence Homology, Amino Acid
  • Staphylococcus aureus / metabolism*


  • Bacterial Proteins
  • DNA Primers
  • Membrane Proteins
  • Hydroxylamine
  • Aminoacyltransferases
  • sortase A
  • Cysteine Endopeptidases
  • Cysteine