ATP-binding cassette domain of hemolysin B, subfamily C
The ABC-transporter hemolysin B is a central component of the secretion machinery that translocates the toxin, hemolysin A, in a Sec-independent fashion across both membranes of E. coli. The hemolysin A (HlyA) transport machinery is composed of the ATP-binding cassette (ABC) transporter HlyB located in the inner membrane, hemolysin D (HlyD), also anchored in the inner membrane, and TolC, which resides in the outer membrane. HlyD apparently forms a continuous channel that bridges the entire periplasm, interacting with TolC and HlyB. This arrangement prevents the appearance of periplasmic intermediates of HlyA during substrate transport. Little is known about the molecular details of HlyA transport, but it is evident that ATP-hydrolysis by the ABC-transporter HlyB is a necessary source of energy.
Jiyao W et al.(2023). "The conserved domain database in 2023.",