Collagen-binding outer membrane protein forming a fibrillar matrix on the bacterial cell surface. Promotes initial attachment and invasion of eukaryotic cells. Also protects the bacteria by being responsible for agglutination, serum resistance, complement inactivation and phagocytosis resistance. Homotrimer; in gels migrates as monomers, dimers and homotrimers (PubMed:22155776, PubMed:14765110). Does not form trimers with distantly related EibA from E.coli; coexpression was lethal and one of the genes is eliminated in vivo. If the full translocator domain (368-455) is exchanged with that of EibA ('299-392'), will form heterotrimers with EibA and vice-versa (PubMed:22155776). The C-terminal translocator domain is localized in the outer membrane and the passenger domain is at the cell surface. Induced at 37 degrees Celsius by the temperature-dependent transcriptional activator LcrF (VirF). The signal peptide, cleaved at the inner membrane, guides the autotransporter protein to the periplasmic space (By similarity). Then, trimerization and insertion of the C-terminal translocator domain in the outer membrane forms a hydrophilic pore for the translocation of the passenger domain to the bacterial cell surface (PubMed:22155776). Presents a lollipop-shaped form which consists of three domains: a C-terminal membrane-anchor domain, a coiled-coil stalk domain and an oval N-terminal head domain. The N-terminal half of the sequence reveals the presence of repeated motifs with the consensus sequence NSVAIGXXS. They form the turns and hydrophobic core of the nine-coiled left-handed parallel beta-roll and trimer structure essential for the collagen-binding activity (PubMed:10931316). Belongs to the autotransporter-2 (AT-2) (TC 1.B.40) family.