Assembly of pili on the surface of Bacillus cereus vegetative cells

• Published in: Molecular microbiology Vol. 66; no. 2; pp. 495 - 510
• Main Authors: Budzik, Jonathan M, Marraffini, Luciano A, Schneewind, Olaf
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-10-2007; Blackwell Publishing Ltd; Blackwell Science
• Subjects: Amino Acid Sequence; Aminoacyltransferases - genetics; Aminoacyltransferases - metabolism; Aminoacyltransferases - physiology; Bacillus anthracis; Bacillus cereus; Bacillus cereus - genetics; Bacillus cereus - metabolism; Bacillus cereus - ultrastructure; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacterial Proteins - physiology; Bacteriology; Biological and medical sciences; Cysteine Endopeptidases - genetics; Cysteine Endopeptidases - metabolism; Cysteine Endopeptidases - physiology; Fimbriae Proteins - genetics; Fimbriae Proteins - metabolism; Fimbriae, Bacterial - genetics; Fimbriae, Bacterial - metabolism; Fimbriae, Bacterial - ultrastructure; Fundamental and applied biological sciences. Psychology; Microbiology; Microscopy, Immunoelectron; Miscellaneous; Protein Subunits - genetics; Protein Subunits - metabolism; Bacteria; Pilus; Bacillus cereus; Bacillales; Bacillaceae; Cell surface
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.2007.05939.x

Vegetative forms of Bacillus cereus are reported to form pili, thin protein filaments that protrude up to 1 μm from the bacterial surface. Pili are assembled from two precursor proteins, BcpA and BcpB, in a manner requiring a pilus-associated sortase enzyme (SrtD). Pili are also formed on the surface of Bacillus anthracis expressing bcpA-srtD-bcpB. BcpA is distributed throughout the entire pilus, whereas BcpB appears positioned at its tip. In agreement with the hypothesis for pilus assembly in Gram-positive bacteria, BcpA encompasses the YPK pilin motif and the LPXTG sorting signal, each of which is absolutely required for the incorporation of BcpA and BcpB into pili. In contrast to BcpB, which relies on the presence of BcpA for incorporation into pili, BcpA fibre assembly occurs even in the absence of BcpB. B. anthracis sortase A (srtA), but not sortase B (srtB) or C (srtC), is required for proper anchoring of pili to the bacterial envelope, suggesting that BcpA/BcpB pili are linked to peptidoglycan cross-bridges.