Part of the ABC transporter complex HlyBD involved in hemolysin export. Transmembrane domains (TMD) form a pore in the inner membrane and the ATP-binding domain (NBD) is responsible for energy generation. Homodimer. In HlyB the peptidase C39 domain, the ATP-binding domain (NBD) and the transmembrane domain (TMD) are fused. The complex HlyBD-TolC (OMF) forms a single transport channel across the two membranes, allowing direct export of alpha-hemolysin. This channel is involved in type 1 secretion system. Belongs to the ABC transporter superfamily. Protein-1 exporter (TC 3.A.1.109) family. Tyr-9 is present instead of the conserved Cys which is expected to be the active site residue of peptidase C39. Thus this protein is presumed to be without peptidase activity.