NDH-1 shuttles electrons from NADH, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory chain. 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 (By similarity). a quinone + 5 H(+)(in) + NADH = a quinol + 4 H(+)(out) + NAD(+) Binds 1 [2Fe-2S] cluster per subunit. Binds 3 [4Fe-4S] clusters per subunit. Belongs to the complex I 75 kDa subunit family.