Multiple forms of the major phenylalanine specific protease in Treponema denticola

The 160,1 90 and 270 kDa outer sheath proteases of Treponema denticola ATCC 35404 were found to be multiple forms of the major 91 kDa phenylalanine protease (PAP) by immunoblotting using anti-91kDa specific antibodies. Multiple forms of the phenylalanine protease were also found in 2 other T. denticola strains studied, ATCC 33520 and the clinical isolate GM-1. Protein, proteolytic and Western blot analyses using antibodies against the PAP and the major outer sheath protein (MSP) indicated that the 190 and 270 kDa proteases were protein complexes formed by the MSP and the PAP. These complexes dissociated by storage in 0.3% or higher SDS concentrations. The purified PAP was found to completely degrade keratin, but was unable to degrade native actin either in its monomeric or polymerized form. The association of the MSP adhesin with a protease capable of degrading host native proteins may benefit the obtention of protein-based nutrients necessary to support the growth of these treponemes. These complexes may also play a role in the structural organization of T. denticola outer sheath.