<p>The six subunit complex RnfABCDGE in <taxon tax_id="1061">Rhodobacter capsulatus</taxon> (Rhodopseudomonas capsulata) encodes an apparent NADH oxidoreductase responsible for electron transport to nitrogenase, necessary for nitrogen fixation. A closely related complex in <taxon tax_id="562">Escherichia coli</taxon>, RsxABCDGE (Reducer of SoxR), reduces the 2Fe-2S-containing superoxide sensor SoxR, active as a transcription factor when oxidized. This family of putative NADH oxidoreductase complexes exists in many of the same species as the related NQR, a Na(+)-translocating NADH-quinone reductase, but is distinct. This entry describes the B subunit.</p> Electron transport complex, RnfB