Part of a membrane-bound complex that couples electron transfer with translocation of ions across the membrane (By similarity). Required to maintain the reduced state of SoxR. Probably transfers electron from NAD(P)H to SoxR (PubMed:12773378). The complex is composed of six subunits: RsxA, RsxB, RsxC, RsxD, RsxE and RsxG. Belongs to the NqrDE/RnfAE family.