Inactivation of a gene for a fibronectin-binding protein of the oral bacterium Streptococcus mutans partially impairs its adherence to fibronectin

Abstract

A sequence of 1,647 base pairs in length of S. mutans DNA that encodes for a 63 kDa protein with significant amino acid similarity with fibronectin-binding proteins of S. pyogenes and S. gordonii was cloned. The putative recombinant fibronectin-binding protein of S. mutans was purified using affinity chromatography and the cloned protein was used to prepare polyclonal antibodies against the recombinant protein. In immunoblot assays, antibodies against the S. pyogenes fibronectinbinding protein, FBP54, were cross-reactive with the S. mutans protein that was designated SmFnB. Additionally, antibodies to the S. mutans SmFnB protein reacted with the S. pyogenes FBP54 protein.The S. mutans SmFnB protein was found to bind to immobilized fibronectin in a concentration dependant manner. A mutant strain of S. mutans M51 that was constructed by alleleic exchange did not express the SmFnB protein. This mutant strain, S. mutans ΔSmFnB, was determined in an ELISA to bind to immobilized fibronectin 30% less when compared to the parental strain S. mutans M51. The results are consistent with the conclusion that the 63 kDa SmFnB protein of S. mutans is a fibronectin-binding protein that may contribute to the interaction of S. mutans with damaged heart tissue during pathogenesis of infective endocarditis. Also, the study suggests that multiple molecules may mediate the interaction of S. mutans with fibronectin.

Multilocus sequence typing analysis of Streptococcus mutans strains with the cnm gene encoding collagen-binding adhesin

“…Moreover, continuous detections of this bacterium in specimens from patients suffering from such disease emphasize the importance of S. mutans in IE (Gauduchon et al, 2001;Nomura et al, 2006;Vose et al, 1987;Ullman et al, 1988). Indeed, studies to clarify specific components involved in IE in S. mutans have also been performed worldwide (Beg et al, 2002;Jung et al, 2009; MatsumotoNakano et al, 2009;Miller-Torbert et al, 2008).…”

“…On: Fri, 11 May 2018 21:36:29 involved in IE in S. mutans have also been performed worldwide (Beg et al, 2002;Jung et al, 2009;MatsumotoNakano et al, 2009;Miller-Torbert et al, 2008).…”

“…Moreover, continuous detections of this bacterium in specimens from patients suffering from such disease emphasize the importance of S. mutans in IE (Gauduchon et al, 2001;Nomura et al, 2006;Vose et al, 1987;Ullman et al, 1988). Indeed, studies to clarify specific components involved in IE in S. mutans have also been performed worldwide (Beg et al, 2002;Jung et al, 2009; MatsumotoNakano et al, 2009;Miller-Torbert et al, 2008).IE is initiated by the binding of bacterial surface molecules to host extracellular matrix (ECM) proteins exposed on damaged heart tissue (Moreillon & Que, 2004). In S. mutans, collagen-binding adhesin or Cnm protein, encoded by the cnm gene, was reported as a strain-specific collagen-binding molecule (Sato et al, 2004).…”

The Fibronectin-Binding Protein Fnm Contributes to Adherence to Extracellular Matrix Components and Virulence of Enterococcus faecium

“…PavA homologues have been identified in other streptococci; these include Streptococcus gordonii FbpA (20), Streptococcus pyogenes FBP54 (21,22), and Streptococcus mutans SmFnB (23). A similar report showed that SfbA, a PavA homologue of group B streptococci, is important in the interaction of these bacteria with the blood-brain barrier endothelium and in the pathogenesis of neonatal meningitis (24).…”

The Fibronectin-Binding Protein EfbA Contributes to Pathogenesis and Protects against Infective Endocarditis Caused by Enterococcus faecalis

“…Similar to the pneumococcal adherence and virulence factor A (PavA) of Streptococcus pneumoniae, EfbA displays an unconventional structure for adhesins in that it lacks an N-terminal signal sequence for targeting the protein to the Sec system and a C-terminal LPXTG cell wall anchorage motif (14-16). Homologous proteins lacking these motifs include Fbp54 of Streptococcus pyogenes (17), FbpA of Streptococcus gordonii (18), the Streptococcus mutants SmFnB (19), and the group B streptococcus SfbA (20), collectively referred to as PavA-like proteins, several of which were shown to be involved in bacterial adherence to fibronectin and/or to mediate virulence in experimental models (15)(16)(17)(18)(19)(20)(21).E. faecalis JH2-2 EfbA consists of an N-terminal predicted domain involved in fibronectin binding (FbpA; amino acids 4 to 429), followed by a domain of unknown function (Duf814; amino acids 448 to 533) often observed in association with FbpA.…”