Functional and structural properties of CbpA, a collagen-binding protein from Arcanobacterium pyogenes

Abstract

Arcanobacterium pyogenes, an opportunistic pathogen of economically important food animals, is the causative agent of liver abscesses in feedlot cattle, osteomyelitis in turkeys, and pneumonia and arthritis in pigs. Previous studies identified the first A. pyogenes adhesin, CbpA, a protein located on the bacterial surface which has the ability to bind collagen and promotes adhesion to the host cells. The protein has an N-terminal ligand-binding region (region A) and a C-terminal repetitive domain (region B). In this study we found that CbpA bound to almost all the collagen types tested but not to other proteins, and it displayed a propensity to interact with several collagenous peptides derived by CNBr cleavage of type I and II collagens. The K D values of CbpA for type I and II collagens and collagen peptides determined by solid-phase binding assay and intrinsic tryptophan fluorescence were in the range of 1-15 nM. It was also found that CbpA and its A region bound fibronectin, and that collagen and fibronectin interacted with distinct subsites. Anti-CbpA antibodies were effective at inhibiting both binding of isolated CbpA and bacterial adhesion to immobilized collagen, suggesting that CbpA is a functional collagen-binding adhesin. Analysis of the immunological cross-reactivity of CbpA with antibodies against other bacterial collagen-binding proteins indicated that CbpA is immunologically related to ACE from Enterococcus faecalis but not to CNA from Staphylococcus aureus or Acm from Enterococcus faecium. Far-UV and near-UV circular dichroism spectra showed that full-length CbpA and its region A are mainly composed of b-sheet with only a minor a-helical component and that both the proteins have a well-defined tertiary structure.

Properties and antimicrobial susceptibility of Trueperella pyogenes isolated from bovine mastitis in China

“…The plo gene was also detected in all of our T. pyogenes strains isolated from bovine mastitis cases. Collagen-binding protein (CbpA) is a virulence factor necessary for adhesion to host cells (Esmay et al, 2003;Pietrocola et al, 2007). In the present study, the cbpA gene encoding this protein was detected in all isolates (100%), while it was reported to have been recovered from 21% of bovine mastitis isolates (Zastempowska and Lassa, 2012).…”

A Collagen-Binding Adhesin, Acb, and Ten Other Putative MSCRAMM and Pilus Family Proteins of Streptococcus gallolyticus subsp. gallolyticus ( Streptococcus bovis Group, Biotype I)

“…The highest affinity of rAcb 35 was observed to collagen type I, with an apparent K D (equilibrium dissociation constant) of 4.5 ϫ 10 Ϫ8 M, followed by collagen type IV (K D ϭ 3.2 ϫ 10 Ϫ7 M) and collagen type V (K D ϭ 5.3 ϫ 10 Ϫ7 M). These estimated affinity values for collagen are in a range similar to or lower than those reported previously for Cna, Acm, Ace, or CpbA (42,48,51,53).…”

Complete Genome Sequence of Trueperella pyogenes, an Important Opportunistic Pathogen of Livestock

“…Its primary virulence factor, pyolysin, is a potent cholesterol-dependent cytolysin and is associated with the tissue damage caused by T. pyogenes infection (1, 12). T. pyogenes also expresses a number of surface-exposed proteins, such as fimbriae, neuraminidases, and extracellular matrix-binding proteins, which are involved in adherence and mucosal colonization (1, 6, 13). …”