Figure 2
From: Strategies of exploitation of mammalian reservoirs by Bartonella species
Hypothetical models of the architectures of the VirB/D4 and Trw T4SS, the VirB/D4 system possesses an inner membrane protein VirD4, the T4CP. External to the outer membrane, VirB4 and VirB11 energize the secretion process. VirB3, 6, 8, 9 and 10 are thought to form a secretion channel bridging the inner membrane and the surface exposed pilus associated components VirB2 and VirB5. The Bep proteins are secreted via this system. Trw has a similar structure to VirB/D4, with homologs for all VirB proteins except VirD4, which Trw lacks. Unlike VirB/D4, Trw expresses multiple variant copies of TrwL and TrwJ. Abbreviations: EX: extracellular matrix, OM: outer membrane, PP: periplasm, IM: inner membrane, CY: cytoplasm.