InterPro domain: IPR007763

This entry includes the NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 12 (NDUFA12) and the NADH dehydrogenase [ubiquinone] 1 alpha subcomplex assembly factor 2 (NDUFAF2). NDUFA12 is an accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) [ 1 , 2 ]. NDUFA12 is believed not to be involved in catalysis [ 3 ]. NDUFAF2 is a paralogue of the structural subunit NDUFA12 and functions as an assembly factor [ 4 ].

NADH:ubiquinone oxidoreductase (complex I) ( 7.1.1.2 ) 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) [ 5 ]. Complex I is a major source of reactive oxygen species (ROS) that are predominantly formed by electron transfer from FMNH(2). Complex I is found in bacteria, cyanobacteria (as a NADH-plastoquinone oxidoreductase), archaea [ 6 ], mitochondria, and in the hydrogenosome, a mitochondria-derived organelle. In general, the bacterial complex consists of 14 different subunits, while the mitochondrial complex contains homologues to these subunits in addition to approximately 31 additional proteins [ 7 ].

1. The gross structure of the respiratory complex I: a Lego System. Biochim. Biophys. Acta 1608, 1-9
2. Accessory subunits are integral for assembly and function of human mitochondrial complex I. Nature 538, 123-126
3. The subunit composition of the human NADH dehydrogenase obtained by rapid one-step immunopurification. J. Biol. Chem. 278, 13619-22
4. Novel insights into the role of Neurospora crassa NDUFAF2, an evolutionarily conserved mitochondrial complex I assembly factor. Mol. Cell. Biol. 33, 2623-34
5. The NADH:ubiquinone oxidoreductase (complex I) of respiratory chains. Q. Rev. Biophys. 25, 253-324
6. The respiratory complex I of bacteria, archaea and eukarya and its module common with membrane-bound multisubunit hydrogenases. FEBS Lett. 479, 1-5
7. Assembly of the Escherichia coli NADH:ubiquinone oxidoreductase (complex I). Biochim. Biophys. Acta 1777, 735-9