DsbE, also called CcmG, is a reducing Dsb protein implicated in electron transfer for cytochrome c maturation in the periplasm of Escherichia coli. DsbE is one of 12 proteins required for their assembly in the periplasm. Its postulated function is to reduce disulphide bonds formed between correctly paired cysteine residues in the cytochrome c apoproteins prior to haem attachment by CcmF and CcmH.