Pili with strong attachments: Gram-positive bacteria do it differently

Mol Microbiol. 2006 Oct;62(2):320-30. doi: 10.1111/j.1365-2958.2006.05279.x. Epub 2006 Sep 15.


Bacteria attach to their appropriate environmental niche by using adhesins. To maximize their contact with the environment, adhesins are often present on the ends of long hairlike structures called pili. Recently, attention has focused on pili of Gram-positive bacteria because they may be vaccine candidates in important human pathogens. These pili differ from the well-studied pili of Gram-negative bacteria because their subunits are covalently linked, they do not require specific chaperones for assembly, and the tip protein (likely to be the adhesin) is not required to initiate formation of the pilus structure. In Gram-positive bacteria, the genes for pili occur in clusters, which may constitute mobile genetic elements. These clusters include the transpeptidase(s) of the sortase family that is/are required for polymerization of the subunit proteins. However, efficient covalent attachment of the completed pilus structure to the cell wall is accomplished, in cases where this has been studied, by the 'housekeeping' sortase, which is responsible for attachment to the peptidoglycan of most surface proteins containing cell wall sorting signals. This enzyme is encoded elsewhere on the genome. Because pili of Gram-positive bacteria have not been extensively investigated yet, we hope that this MicroReview will help to pinpoint the areas most in need of further study.

Publication types

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

MeSH terms

  • Adhesins, Bacterial / genetics
  • Adhesins, Bacterial / metabolism
  • Aminoacyltransferases / genetics
  • Aminoacyltransferases / metabolism
  • Bacterial Adhesion / genetics
  • Bacterial Adhesion / physiology
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Cysteine Endopeptidases / genetics
  • Cysteine Endopeptidases / metabolism
  • Fimbriae Proteins / genetics
  • Fimbriae Proteins / metabolism
  • Fimbriae, Bacterial / metabolism*
  • Gram-Positive Bacteria / genetics
  • Gram-Positive Bacteria / metabolism*
  • Gram-Positive Bacteria / physiology
  • Models, Biological
  • Multigene Family / genetics


  • Adhesins, Bacterial
  • Bacterial Proteins
  • Fimbriae Proteins
  • Aminoacyltransferases
  • sortase A
  • Cysteine Endopeptidases