This sub-family represents a carboxyl terminal extension of pfam00361. It includes subunit 5 from chloroplasts, and bacterial subunit L. This sub-family is part of complex I which catalyzes the transfer of two electrons from NADH to ubiquinone in a reaction that is associated with proton translocation across the membrane. This family is largely a few TM regions of the F subunit of NADH-Ubiquinone oxidoreductase from plants. The TMs form part of the anti-porter subunit.