PG27 is a novel membrane protein essential for a Porphyromonas gingivalis protease secretion system.

Porphyromonas gingivalis secretes endopeptidase gingipains, which are important virulence factors of this bacterium. Gingipains are transported across the inner membrane via the Sec system, followed by transport across the outer membrane via an unidentified pathway. The latter transport step is suggested to be mediated via a novel protein secretion pathway.