Signal peptide of FadA adhesin from Fusobacterium nucleatum plays a novel structural role by modulating the filament's length and width

FEBS Lett. 2012 Jan 2;586(1):1-6. doi: 10.1016/j.febslet.2011.10.047. Epub 2011 Nov 19.


FadA, a novel adhesin of periodontal pathogen Fusobacterium nucleatum is composed of two forms, pre-FadA and mature FadA (mFadA), constituting the functional FadA complex (FadAc). By electron microscopy, we observed that mFadA formed uniformly long and thin filaments, while FadAc formed heterogeneous filaments of varying lengths and widths, as well as "knots". Mutants in signal peptide or in the non-alpha-helical loop retaining heterogeneous structures had binding activity while those forming aggregates or long filaments lost activity. These observations suggest short filaments and knots may be the active forms of FadA. This is the first demonstration that a signal peptide is required for the assembly of a bacterial adhesin.

Publication types

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

MeSH terms

  • Adhesins, Bacterial / chemistry*
  • Adhesins, Bacterial / genetics
  • Adhesins, Bacterial / metabolism*
  • Animals
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • Fusobacterium nucleatum / chemistry
  • Fusobacterium nucleatum / ultrastructure
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • Microscopy, Electron
  • Mutation
  • Protein Conformation
  • Protein Sorting Signals*


  • Adhesins, Bacterial
  • Protein Sorting Signals