Mrp superfamily
The Na+ Transporting Mrp Superfamily is a superfamily of integral membrane transport proteins.
It includes the TC families:
- The Monovalent Cation (K+ or Na+):Proton Antiporter-3 (CPA3) Family
- The H+ or Na+-translocating NADH Dehyrogenase (NDH) Family
- The H+-translocating F420H2 Dehydrogenase (F420H2DH) Family
Mrp of Bacillus subtilis is a 7 subunit Na+/H+ antiporter complex . All subunits are homologous to the subunits in other members of this monovalent cation :proton antiporter-3 family as well as subunits in the archaeal hydrogenases, which share several subunits with NADH dehydrogenase subunits. The largest subunits of the Mrp complex are homologous to subunits in NADH dehydrogenases : ND2, ND4 and ND5 in the fungal NADH dehydrogenase complex and most other NDHs, as well as subunits in the F420H2 dehydrogenase of Methanosarcina mazei . These homologous subunits may catalyze Na+/K+ and/or H+ transport.