9.B.355. The Dentilisin (Dentilisin) Family
The Treponema denticola outer membrane lipoprotein-protease complex (Dentilisin) contributes to periodontal disease by degrading extracellular matrix components and disrupting intercellular host signaling pathways (Godovikova et al. 2011). prcB, located upstream of and cotranscribed with prcA and prtP, encodes a 22-kDa lipoprotein that interacts with PrtP and is required for its activity. PrcB migrates in native gels as part of a >400-kDa complex that includes PrtP and PrcA, as well as the major outer sheath protein Msp. Though it lacks the canonical ribosome binding site present upstream of both prcA and prtP, PrcB is present at levels similar to those of PrtP in whole-cell extracts. Immunofluorescence microscopy demonstrated cell surface exposure of the mature forms of PrtP, PrcA1, PrcB, and Msp. The 16-kDa N-terminal acylated fragment of PrtP (predicted to be released during activation of PrtP) was present in cell extracts but was detected neither in the purified active protease complex nor on the cell surface. PrcA2, detectable on the surface of Msp-deficient cells but not that of wild-type cells, coimmunoprecipitated with Msp. These results indicate that PrcB is a component of the outer membrane lipoprotein protease complex and that the Msp and PrcA2 interaction may mediate formation of a very-high-molecular-weight outer membrane complex (Godovikova et al. 2011).