Sortase B, a new class of sortase in Listeria monocytogenes.
Sortases are transamidases that covalently link proteins to the peptidoglycan of gram-positive bacteria. The genome of the pathogenic bacterium Listeria monocytogenes encodes two sortases genes, srtA and srtB. The srtA gene product anchors internalin and some other LPXTG-containing proteins to the listerial surface. Here, we focus on the role of the second sortase, SrtB. Whereas SrtA acts on most of the proteins in the peptidoglycan fraction, SrtB appears to target minor amounts of surface polypeptides. We identified one of the SrtB-anchored proteins as the virulence factor SvpA, a surface-exposed protein which does not contain the LPXTG motif. Therefore, as in Staphylococcus aureus, the listerial SrtB represents a second class of sortase in L. monocytogenes, involved in the attachment of a subset of proteins to the cell wall, most likely by recognizing an NXZTN sorting motif. The DeltasrtB mutant strain does not have defects in bacterial entry, growth, or motility in tissue-cultured cells and does not show attenuated virulence in mice. SrtB-mediated anchoring could therefore be required to anchor surface proteins involved in the adaptation of this microorganism to different environmental conditions.
Bierne
Hélène
H
Unité des Interactions Bactéries-Cellules, Institut Pasteur, 75724 Paris Cedex 15, France.
Garandeau
Caroline
C
Pucciarelli
M Graciela
MG
Sabet
Christophe
C
Newton
Salete
S
Garcia-del Portillo
Francisco
F
Cossart
Pascale
P
Charbit
Alain
A
D000595:Amino Acid Sequence; D019881:Aminoacyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003546:Cysteine Endopeptidases; D005260:Female; D008089:Listeria monocytogenes / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D008088:Listeriosis / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D014774:Virulence
D001426:Bacterial Proteins; D008565:Membrane Proteins; C443120:SvpA protein, Listeria monocytogenes; D019881:Aminoacyltransferases; C120542:sortase A; D003546:Cysteine Endopeptidases