Structural insights into serine-rich fimbriae from Gram-positive bacteria

J Biol Chem. 2010 Oct 15;285(42):32446-57. doi: 10.1074/jbc.M110.128165. Epub 2010 Jun 28.


The serine-rich repeat family of fimbriae play important roles in the pathogenesis of streptococci and staphylococci. Despite recent attention, their finer structural details and precise adhesion mechanisms have yet to be determined. Fap1 (Fimbriae-associated protein 1) is the major structural subunit of serine-rich repeat fimbriae from Streptococcus parasanguinis and plays an essential role in fimbrial biogenesis, adhesion, and the early stages of dental plaque formation. Combining multidisciplinary, high resolution structural studies with biological assays, we provide new structural insight into adhesion by Fap1. We propose a model in which the serine-rich repeats of Fap1 subunits form an extended structure that projects the N-terminal globular domains away from the bacterial surface for adhesion to the salivary pellicle. We also uncover a novel pH-dependent conformational change that modulates adhesion and likely plays a role in survival in acidic environments.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Adhesion / physiology*
  • Crystallography, X-Ray
  • Fimbriae Proteins / chemistry*
  • Fimbriae Proteins / genetics
  • Fimbriae Proteins / metabolism
  • Fimbriae, Bacterial / chemistry
  • Fimbriae, Bacterial / ultrastructure*
  • Gram-Positive Bacteria / chemistry
  • Gram-Positive Bacteria / genetics
  • Gram-Positive Bacteria / ultrastructure*
  • Hydrogen-Ion Concentration
  • Models, Molecular
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Conformation*
  • Scattering, Small Angle
  • Serine / genetics*
  • Streptococcus / chemistry*
  • Streptococcus / genetics
  • Streptococcus / ultrastructure


  • fap1 protein, Streptococcus
  • Fimbriae Proteins
  • Serine

Associated data

  • PDB/2KUB