Peptide Mapping of a Functionally Versatile Fimbrial Adhesin from Porphyromonas gingivalis
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Porphyromonas gingivalis is strongly implicated in adult periodontitis. This oral pathogen expresses adhesive filamentous appendages, known as fimbriae, which constitute one of its major virulence factors. Fimbriae are composed of polymerized fimbrillin (FimA) subunits and play an indispensable role in the ability of P. gingivalis to colonize and invade periodontal tissue and to induce alveolar bone loss. The virulence potential of fimbriae is attributable to their capacity to interact with various dental or epithelial substrates, extracellular matrix proteins, other bacteria, and host immune cells. It has been puzzling whether the multifunctional adhesive ability of fimbriae results from multiple adhesion epitopes specific for each receptor, or whether fimbriae contain versatile structural motifs that are recognizable by multiple receptors. This review summarizes peptide mapping studies that have defined functional epitopes of P. gingivalis fimbriae. Available evidence suggests that the binding of fimbriae to various receptors generally involves specific amino acid sequences of the FimA subunit, although the same FimA peptide may occasionally recognize different receptors. Moreover, in cases where distinct FimA peptides interact with the same receptor, the peptides involved share common sequences. It therefore appears that the promiscuous binding reactivity of P. gingivalis fimbriae is attributable to a multitude of adhesion epitopes which however share minimal binding elements, although the overall hydrophobicity and polymeric nature of fimbriae may significantly enhance the avidity of binding interactions. Peptide mapping of fimbriae is significant also for translational purposes, such as for development of subunit vaccines that contain defined immunogenic and functionally important epitopes and for identification of peptides that can competitively inhibit virulence activities of P. gingivalis fimbriae.
Keywordsbacterial adhesion epitopes extracellular matrix fimbriae P. gingivalis pattern-recognition receptors peptide mapping salivary proteins
microbe-associated molecular pattern;
proline-rich protein 1;
tumor necrosis factor-α
The author would like to thank Pukar Ratti and Evlambia Harokopakis for their contribution in the peptide mapping study (Hajishengallis et al., 2005) discussed in this review. Studies performed in the author’s lab and cited in this review were supported by U.S. Public Health Service Grant DE015254 from the NIDCR, National Institutes of Health.
- Hajishengallis, G., Wang, M., Harokopakis, E., Triantafilou, M. and Triantafilou, K.: 2006b Infect. Immune. 74(10), 5658–5666Google Scholar
- Hongo, H., Takano, H. and Morita, M. :2006, J. Perodont. Res. 41, (doi:10.1111/j.1600–0765.2006.00922.x (In Press)Google Scholar
- Ogawa T., Ogo H., Hamada S. (1994a) Oral. Microbiol. Immunol. 9(5):257–261Google Scholar
- Ogawa T., Uchida H., Hamada S. (1994b) FEMS Microbiol. Lett. 116(2):237–242Google Scholar
- Roth, G. A., Moser, B., Roth-Walter, F., Giacona, M. B., Harja, E., Papapanou, P. N., et al.: 2006, Atherosclerosis 190(2), 271–281Google Scholar
- Zambon J. J., Grossi S., Dunford R., Harazsthy V. I., Preus H., Genco R. J. (1994). in Genco R. J., Hamada S., Lehrer J. R., McGhee J. R., Mergenhangen S. (eds.) Molecular Pathogenesis of Periodontal Disease. Washington, D.C.: Am. Soc. Microbiol., pp. 3–12Google Scholar