NADH-ubiquinone oxidoreductase-G iron-sulfur binding region
SMART accession number:SM00929
Interpro abstract (IPR019574):

NADH:ubiquinone oxidoreductase (complex I) (EC 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) [(PUBMED:1470679)]. 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 [(PUBMED:10940377)], 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 [(PUBMED:18394423)].

Mitochondrial complex I, which is located in the inner mitochondrial membrane, is the largest multimeric respiratory enzyme in the mitochondria, consisting of more than 40 subunits, one FMN co-factor and eight FeS clusters [(PUBMED:18563446)]. The assembly of mitochondrial complex I is an intricate process that requires the cooperation of the nuclear and mitochondrial genomes [(PUBMED:18563446), (PUBMED:17854760)]. Mitochondrial complex I can cycle between active and deactive forms that can be distinguished by the reactivity towards divalent cations and thiol-reactive agents. All redox prosthetic groups reside in the peripheral arm of the L-shaped structure. The NADH oxidation domain harbouring the FMN cofactor is connected via a chain of iron-sulphur clusters to the ubiquinone reduction site that is located in a large pocket formed by the PSST and 49kDa subunits of complex I [(PUBMED:18982432)].

This entry describes the G subunit (one of 14 subunits, A to N) of the NADH-quinone oxidoreductase complex I which generally couples NADH and ubiquinone oxidation/reduction in bacteria and mammalian mitochondria while translocating protons, but may act on NADPH and/or plastoquinone in cyanobacteria and plant chloroplasts. This family does not contain related subunits from formate dehydrogenase complexes.

This entry represents the iron-sulphur binding domain of the G subunit.

GO process:oxidation-reduction process (GO:0055114)
GO function:oxidoreductase activity (GO:0016491)
Family alignment:
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There are 1859 NADH-G_4Fe-4S_3 domains in 1858 proteins in SMART's nrdb database.

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