InterPro : IPR010966

Name  NADH:ubiquinone oxidoreductase, Na(+)-translocating, B subunit Short Name  NADH-UbQ_OxRdtase_suB
Type  Family Description  NADH:ubiquinone oxidoreductase (complex I) () 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) []. 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 [], 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 []. This entry represents the NqrB subunit of the six-protein (NqrA to NqrF), membrane-associated Na(+)-pumping NADH-quinone reductase of a number of marine and pathogenic Gram-negative bacteria []. The Nqr complex catalyses the reduction of ubiquinone-1 to ubiquinol by two successive reactions, coupled with the transport of sodium ions from the cytoplasm to the periplasm. NqrA to NqrE are probably involved in the second step, the conversion of ubisemiquinone to ubiquinol. Both the NqrB and NqrC subunits contain a FMN cofactor that is covalently attached by a phosphate group to a threonine residue [].

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

0 Contains

0 Found In

1 Parent Features

Id Name Short Name Type
IPR004338 NADH-quinone reductase NQR2/RnfD NADH_Q_Rdtase_NQR2_RnfD Family

5 Publications

First Author Title Year Journal Volume Pages
Walker JE The NADH:ubiquinone oxidoreductase (complex I) of respiratory chains. 1992 Q Rev Biophys 25 253-324
Friedrich T The respiratory complex I of bacteria, archaea and eukarya and its module common with membrane-bound multisubunit hydrogenases. 2000 FEBS Lett 479 1-5
Schneider D Assembly of the Escherichia coli NADH:ubiquinone oxidoreductase (complex I). 2008 Biochim Biophys Acta 1777 735-9
Hayashi M FMN is covalently attached to a threonine residue in the NqrB and NqrC subunits of Na(+)-translocating NADH-quinone reductase from Vibrio alginolyticus. 2001 FEBS Lett 488 5-8
Barquera B Purification and characterization of the recombinant Na(+)-translocating NADH:quinone oxidoreductase from Vibrio cholerae. 2002 Biochemistry 41 3781-9

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)