InterPro domain: IPR039428

This entry includes NADH:ubiquinone oxidoreductase, chain 4L and bacterial Mnh complex subunit C. They share significant protein sequence similarity [ 1 ].

ADH:ubiquinone oxidoreductase (complex I) ( 1.6.5.3 ) is a respiratory-chain enzyme that catalyses the transfer of two electrons from NADH to ubiquinone in a reaction that is associated with proton translocation across the membrane (NADH + ubiquinone = NAD+ + ubiquinol) [ 2 ]. In eukaryotes, NADH:ubiquinone oxidoreductase, chain 4L is usually found in either mitochondria or chloroplasts as part of the respiratory-chain NADH dehydrogenase (also known as complex I orNADH-ubiquinone oxidoreductase), an oligomeric enzymatic complex [ 3 ]. However, it is also found in bacteria [ 4 ] and archaea [ 5 ] where it is annotated as NuoK subunit.

Mnh subunit C1 is a cation antiporter, involved in K(+) and Na(+) excretion [ 6 ].

1. Catalytic properties of Staphylococcus aureus and Bacillus members of the secondary cation/proton antiporter-3 (Mrp) family are revealed by an optimized assay in an Escherichia coli host. J. Bacteriol. 189, 3081-90
2. The NADH:ubiquinone oxidoreductase (complex I) of respiratory chains. Q. Rev. Biophys. 25, 253-324
3. Tracing the evolution of a large protein complex in the eukaryotes, NADH:ubiquinone oxidoreductase (Complex I). J. Mol. Biol. 348, 857-70
4. Production of reactive oxygen species by complex I (NADH:ubiquinone oxidoreductase) from Escherichia coli and comparison to the enzyme from mitochondria. Biochemistry 47, 3964-71
5. The respiratory complex I of bacteria, archaea and eukarya and its module common with membrane-bound multisubunit hydrogenases. FEBS Lett. 479, 1-5