Homologous Superfamily

NADH-ubiquinone oxidoreductase 51kDa subunit, FMN-binding domain superfamily (IPR037225)

Short name: Nuo51_FMN-bd_sf

Overlapping entries


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) [PMID: 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 [PMID: 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 [PMID: 18394423].

Among the many polypeptide subunits that make up complex I, there is one with a molecular weight of 51kDa (in mammals), which is the second largest subunit of complex I [PMID: 2029890]. The 51kDa subunit, as the corresponding bacterial subunit (Nqo1 in Thermus and NuoF in E. coli) [PMID: 12600193], contains the NADH-binding site, the primary electron acceptor FMN-binding site, and a 4Fe-4S cluster [PMID: 16469879].

This superfamily represents the FMN-binding domain. Its structure is composed of three layers (alpha/beta/alpha) with parallel beta-sheet of four strands.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.