A novel fibronectin type III module binding motif identified on C-terminus of Leptospira immunoglobulin-like protein, LigB

Biochem Biophys Res Commun. 2009 Nov 6;389(1):57-62. doi: 10.1016/j.bbrc.2009.08.089. Epub 2009 Aug 21.


Infection by pathogenic strains of Leptospira hinges on the pathogen's ability to adhere to host cells via extracellular matrix such as fibronectin (Fn). Previously, the immunoglobulin-like domains of Leptospira Lig proteins were recognized as adhesins binding to N-terminal domain (NTD) and gelatin binding domain (GBD) of Fn. In this study, we identified another Fn-binding motif on the C-terminus of the Leptospira adhesin LigB (LigBCtv), residues 1708-1712 containing sequence LIPAD with a beta-strand and nascent helical structure. This motif binds to 15th type III modules (15F(3)) (K(D)=10.70 microM), and association (k(on)=600 M(-1)s(-1)) and dissociation (k(off)=0.0129 s(-1)) rate constants represents a slow binding kinetics in this interaction. Moreover, pretreatment of MDCK cells with LigB(1706-1716) blocked the binding of Leptospira by 39%, demonstrating a significant role of LigB(1706-1716) in cellular adhesion. These data indicate that the LIPAD residues (LigB(1708-1712)) of the Leptospira interrogans LigB protein bind 15F(3) of Fn at a novel binding site, and this interaction contributes to adhesion to host cells.

Publication types

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

MeSH terms

  • Amino Acid Motifs / genetics
  • Amino Acid Sequence
  • Animals
  • Antigens, Bacterial / genetics
  • Antigens, Bacterial / metabolism*
  • Bacterial Adhesion*
  • Cell Culture Techniques
  • Dogs
  • Fibronectins / metabolism*
  • Leptospira / metabolism
  • Leptospira / pathogenicity*
  • Molecular Sequence Data
  • Protein Structure, Tertiary / genetics


  • Antigens, Bacterial
  • Fibronectins
  • LigB-m protein, Leptospira interrogans