Strains of Actinomyces naeslundii and Actinomyces viscosus exhibit structurally variant fimbrial subunit proteins and bind to different peptide motifs in salivary proteins - PubMed (original) (raw)

Comparative Study

Strains of Actinomyces naeslundii and Actinomyces viscosus exhibit structurally variant fimbrial subunit proteins and bind to different peptide motifs in salivary proteins

T Li et al. Infect Immun. 1999 May.

Abstract

Oral strains of Actinomyces spp. express type 1 fimbriae, which are composed of major FimP subunits, and bind preferentially to salivary acidic proline-rich proteins (APRPs) or to statherin. We have mapped genetic differences in the fimP subunit genes and the peptide recognition motifs within the host proteins associated with these differential binding specificities. The fimP genes were amplified by PCR from Actinomyces viscosus ATCC 19246, with preferential binding to statherin, and from Actinomyces naeslundii LY7, P-1-K, and B-1-K, with preferential binding to APRPs. The fimP gene from the statherin-binding strain 19246 is novel and has about 80% nucleotide and amino acid sequence identity to the highly conserved fimP genes of the APRP-binding strains (about 98 to 99% sequence identity). The novel FimP protein contains an amino-terminal signal peptide, randomly distributed single-amino-acid substitutions, and structurally different segments and ends with a cell wall-anchoring and a membrane-spanning region. When agarose beads with CNBr-linked host determinant-specific decapeptides were used, A. viscosus 19246 bound to the Thr42Phe43 terminus of statherin and A. naeslundii LY7 bound to the Pro149Gln150 termini of APRPs. Furthermore, while the APRP-binding A. naeslundii strains originate from the human mouth, A. viscosus strains isolated from the oral cavity of rat and hamster hosts showed preferential binding to statherin and contained the novel fimP gene. Thus, A. viscosus and A. naeslundii display structurally variant fimP genes whose protein products are likely to interact with different peptide motifs and to determine animal host tropism.

PubMed Disclaimer

Figures

FIG. 1

FIG. 1

Amino acid sequence alignment of the FimP major subunit proteins of A. naeslundii T14V (upper sequence) and A. viscosus ATCC 19246 (lower sequence). Identical (|), conserved (:), and similar (.) amino acids are indicated. Boldface indicates a putative N-terminal signal peptide with a cleavage site (↓) and a C-terminal LPXTG sequence. The seven shaded boxes indicate domains, each incorporating a proline residue and reported to be conserved between the FimP and FimA subunit proteins (60).

FIG. 2

FIG. 2

Adhesion of A. naeslundii LY7 (a) and A. viscosus ATCC 19246 (b) to statherin or PRP-1 (0.6 nmol/7 mg of beads) and to statherin- or PRP-1-mimicking decapeptides (17.4 nmol/7 mg of beads) covalently linked to agarose beads. The bars represent the means (plus standard errors) of two independent experiments in which triplicate samples were assayed.

FIG. 3

FIG. 3

Adhesion of A. viscosus ATCC 19246 to varying amounts of statherin-mimicking decapeptides covalently linked to agarose beads. Triplicate determinations were used in two independent experiments. The data are presented as means ± standard errors.

Similar articles

Cited by

References

    1. Amano A, Kataoka K, Raj P A, Genco R J, Shizukuishi S. Binding site of salivary statherin for Porphyromonas gingivalis recombinant fimbrillin. Infect Immun. 1996;64:4249–4254. - PMC - PubMed
    1. Amano A, Sojar H T, Lee J-Y, Sharma A, Levine M J, Genco R J. Salivary receptors for recombinant fimbrillin of Porphyromonas gingivalis. Infect Immun. 1994;62:3372–3380. - PMC - PubMed
    1. Ausubel F M, Brent R, Kingston R E, Moore D D, Seidman J G, Smith J A, Struhl K. Current protocols in molecular biology. Vol. 1. New York, N.Y: John Wiley & Sons, Inc.; 1993. pp. 2.9.16–2.9.20.
    1. Azen E A. Genetics of salivary protein polymorphisms. Crit Rev Oral Biol Med. 1993;4:479–485. - PubMed
    1. Bakker D, Willemsen P T, Simons L H, van Zijderveld F G, de Graaf F K. Characterization of the antigenic and adhesive properties of FaeG, the major subunit of K88 fimbriae. Mol Microbiol. 1992;6:247–255. - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources