Human Plasma Fibronectin Possesses Second Binding Site(s) to Staphylococcus aureus on Its C-Terminal Region1

Abstract

The existence of a second binding site to Staphylococcus aureus on fibronectin was explored by using a recombinant protein, alb-FnBPA, which was obtained from an Escherichia coli clone containing a part of the gene for fibronectin-binding protein of S. aureus. Limited digestion with trypsin produced a 215K fragment from the B chain of fibronectin by releasing an N-terminal 32 kDa region. This C-terminal large fragment captured alb-FnBPA in spite of lacking the N-terminal binding region to S. aureus. This treatment also produced a 185K fragment from A chain by releasing N-terminal 32 kDa and C-terminal 37 kDa regions, and the 185K fragment possessed no binding ability. Thermolysin digestion was also performed to investigate the effect on the binding of releasing the C-terminal region from both of the chains and to locate the binding region to alb-FnBPA on the tryptic 215K fragment. But this digestion produced no fragment binding to alb-FnBPA except for the N-terminal 24K and its transient precursory fragments. These results indicate that both the N-terminal and the C-terminal regions of fibronectin bind to S. aureus, and suggest that the binding appears to involve cooperation between type III repeats and C-terminal type I repeats.

Dissociation Rate Constants of Human Fibronectin Binding to Fibronectin-binding Proteins on Living Staphylococcus aureus Isolated from Clinical Patients

“…It is worth noting that other binding sites have been identified along the lengths of Fn and FnBPs. For example, there is evidence that S. aureus binds to the C-terminal type I and III modules on Fn (39) through FnBPA (40).…”

The A domain of fibronectin‐binding protein B of Staphylococcus aureus contains a novel fibronectin binding site

“…The binding site in Fn for S. aureus FnBPs is located in the N-terminus [20]. However, another binding site in the C-terminal gelatin-binding domain (GBD) has also been reported [21,22]. To facilitate this, shuttle plasmid pfnbBA::RclfA was constructed, which expressed a chimeric protein containing the A domain of FnBPB together with region R and the cell wall anchoring region of S. aureus ClfA (Fig.…”

Staphylococcus aureus adhesion to bone matrix and bone-associated biomaterials

“…A subsequent study [29] has demonstrated that a recombinant protein corresponding to the fourth and ¢fth modules bound to a ¢bronec-tin-binding MSCRAMM, but with a much lower a¤nity compared to the intact amino-terminal domain of ¢bronectin. An additional binding site for S. aureus is also located in the carboxy-terminal portion of the ¢bronectin molecule [30]. This domain may only be present in ¢bronectin in a ¢brillar conformation associated with surfaces and may in that case act synergistically with the N-terminal type I binding sites for binding of S. aureus cells.…”