TlpA-like family, DsbE (also known as CcmG and CycY) subfamily; DsbE is a membrane-anchored, periplasmic TRX-like reductase containing a CXXC motif that specifically donates reducing equivalents to apocytochrome c via CcmH, another cytochrome c maturation (Ccm) factor with a redox active CXXC motif. Assembly of cytochrome c requires the ligation of heme to reduced thiols of the apocytochrome. In bacteria, this assembly occurs in the periplasm. The reductase activity of DsbE in the oxidizing environment of the periplasm is crucial in the maturation of cytochrome c.