bacteria, cleaves sorting signals at the LPXTG motif. We have identified a second sortase
(SrtB) in the Gram-positive pathogen Staphylococcus aureus that is required for anchoring of
a surface protein with a NPQTN motif. Purified SrtB cleaves NPQTN-bearing peptides in
vitro, and a srtB mutant is defective in the persistence of animal infections. srtB is part of an
iron-regulated locus called i ron-responsive s urface d eterminants (isd), which also contains …