UniProt functional annotation for Q56224

UniProt code: Q56224.

Organism: Thermus thermophilus (strain HB8 / ATCC 27634 / DSM 579).
Taxonomy: Bacteria; Deinococcus-Thermus; Deinococci; Thermales; Thermaceae; Thermus.
Function: NDH-1 shuttles electrons from NADH, via FMN and iron- sulfur (Fe-S) centers, to quinones in the respiratory chain. The immediate electron acceptor for the enzyme in this species is menaquinone. Couples the redox reaction to proton translocation (for every two electrons transferred, four hydrogen ions are translocated across the cytoplasmic membrane), and thus conserves the redox energy in a proton gradient required for the synthesis of ATP. The role of the nqo9 subunit appears to provide a 'connecting chain' of two clusters between cluster N5 and the terminal cluster N2, and to stabilize the structure of the complex by interacting with other subunits.
Catalytic activity: NADH + quinone = NAD(+) + quinol.
Cofactor: Binds 2 4Fe-4S clusters per subunit. The 4Fe-4S clusters are referred to as N6a and N6b.
Subunit: NDH-1 is composed of 15 different subunits, nqo1 to nqo15. The complex has a L-shaped structure, with the hydrophobic arm (subunits nqo7, nqo8 and nqo10 to nqo14) embedded in the membrane and the hydrophilic peripheral arm (subunits nqo1 to nqo6, nqo9 and nqo15) protruding into the bacterial cytoplasm. The hydrophilic domain contains all the redox centers.
Subcellular location: Cell membrane; Peripheral membrane protein; Cytoplasmic side.
Similarity: Belongs to the complex I 23 kDa subunit family.
Similarity: Contains 2 4Fe-4S ferredoxin-type domains.

Annotations taken from UniProtKB at the EBI.