ATP-binding cassette domain of nickel/oligopeptides specific transporters
The ABC transporter subfamily specific for the transport of dipeptides, oligopeptides (OppD), and nickel (NikDE). The NikABCDE system of E. coli belongs to this family and is composed of the periplasmic binding protein NikA, two integral membrane components (NikB and NikC), and two ATPase (NikD and NikE). The NikABCDE transporter is synthesized under anaerobic conditions to meet the increased demand for nickel resulting from hydrogenase synthesis. The molecular mechanism of nickel uptake in many bacteria and most archaea is not known. Many other members of this ABC family are also involved in the uptake of dipeptides and oligopeptides. The oligopeptide transport system (Opp) is a five-component ABC transport composed of a membrane-anchored substrate binding proteins (SRP), OppA, two transmembrane proteins, OppB and OppC, and two ATP-binding domains, OppD and OppF.