Putative Treponema pallidum cytadhesins share a common functional domain

Three putative Treponema pallidum ligands (P1, P2, and P3) that bind host fibronectin were characterized by peptide mapping. Papain digestion of each protein yielded a comigrating peptide of approximately 12,000 molecular weight. An antibody to this protein fragment inhibited T. pallidum host cytadherence, indicating that this peptide may be the functional domain of these treponemal adhesins.