Summary Clostridium perfringens is an obligate anaerobic bacterium that can cause gas
gangrene and food poisoning in humans. Our previous studies have revealed that C. perfringens
binds to fibronectin (Fn) and has several Fn-binding proteins (Fbps) on its cell surface. FbpC, one
of the Fbps identified in C. perfringens, does not play a major role in Fn binding, because Fn binds
to fbpC and fbpD null mutants at levels comparable to those of the parental strain. In this study, we
identified the fbpC gene promoter and performed structural and functional prediction of FbpC via
in silico studies and evaluation of FbpC carboxypeptidase activity. FbpC was predicted to be both
a cell wall-binding protein and a carboxypeptidase based on sequence similarity analysis, domain
based annotation, motif-based annotation, and tertiary structure–based functional analyses. The
purified recombinant FbpC exhibited significantly higher carboxypeptidase activity than bovine
serum albumin in vitro. FbpC thus appears to be a carboxypeptidase associated with the cell wall.
