Fig 1.
The T7SSb of Gram-positive bacteria encode primarily membrane-bound machinery including an EssC ATPase, which facilitates the export of small alpha-helical proteins and toxins.
Structural depictions of T7SS machinery proteins as described in [2]. The putative functions of EsxA in T7SSb require further investigation but EsxA may putatively (1) chaperone other T7SS substrates; (2) associate with membrane T7SSb core components; and (3) exhibit cytotoxic and pore-forming activity as secreted effector. While T7SSb substrates are still being elucidated and characterized, the T7SSb as a whole has been shown in many species to play roles in interbacterial competition and virulence.