Part of a complex that catalyzes the reversible reduction of CoM-S-S-CoB to the thiol-coenzymes H-S-CoM (coenzyme M) and H-S-CoB (coenzyme B) (PubMed:9654152, PubMed:9665708, PubMed:11034998). Electrons probably transfer from phenazine to the high potential 4Fe cluster in HdrD subunit, then to the low potential heme in HdrE subunit and finally to CoM-S-S-CoB (PubMed:11034998). coenzyme B + coenzyme M + methanophenazine = coenzyme M-coenzyme B heterodisulfide + dihydromethanophenazine Binds 2 [4Fe-4S] cluster. kcat is 74 sec(-1) at 25 degrees Celsius. Cofactor metabolism; coenzyme M-coenzyme B heterodisulfide reduction; coenzyme B and coenzyme M from coenzyme M-coenzyme B heterodisulfide: step 1/1. The dihydromethanophenazine:CoB--CoM heterodisulfide reductase is composed of two subunits; HdrD and HdrE. Methanophenazine seems to mediate electron transfer from F(420)H(2) dehydrogenase to the dihydromethanophenazine:CoB--CoM heterodisulfide reductase. Belongs to the HdrD family.