Sortase D forms the covalent bond that links BcpB to the tip of Bacillus cereus pili

J Biol Chem. 2009 May 8;284(19):12989-97. doi: 10.1074/jbc.M900927200. Epub 2009 Mar 5.

Abstract

Bacillus cereus and other Gram-positive bacteria elaborate pili via a sortase D-catalyzed transpeptidation mechanism from major and minor pilin precursor substrates. After cleavage of the LPXTG sorting signal of the major pilin, BcpA, sortase D forms an amide bond between the C-terminal threonine and the amino group of lysine within the YPKN motif of another BcpA subunit. Pilus assembly terminates upon sortase A cleavage of the BcpA sorting signal, resulting in a covalent bond between BcpA and the cell wall cross-bridge. Here, we show that the IPNTG sorting signal of BcpB, the minor pilin, is cleaved by sortase D but not by sortase A. The C-terminal threonine of BcpB is amide-linked to the YPKN motif of BcpA, thereby positioning BcpB at the tip of pili. Thus, unique attributes of the sorting signals of minor pilins provide Gram-positive bacteria with a universal mechanism ordering assembly of pili.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amides / metabolism
  • Aminoacyltransferases / genetics
  • Aminoacyltransferases / metabolism*
  • Anthrax / genetics
  • Anthrax / metabolism
  • Bacillus anthracis / genetics
  • Bacillus anthracis / metabolism
  • Bacillus cereus / genetics
  • Bacillus cereus / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cell Wall / metabolism*
  • Chromatography, Affinity
  • Cysteine Endopeptidases / genetics
  • Cysteine Endopeptidases / metabolism*
  • Fimbriae Proteins / genetics
  • Fimbriae Proteins / metabolism*
  • Fimbriae, Bacterial / genetics
  • Fimbriae, Bacterial / metabolism*
  • Peptide Fragments / metabolism*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Substrate Specificity

Substances

  • Amides
  • Bacterial Proteins
  • Peptide Fragments
  • sortase D
  • Fimbriae Proteins
  • Aminoacyltransferases
  • sortase A
  • Cysteine Endopeptidases