DsbE

DsbE is a periplasmic thiol-disulfide oxidoreductase that is part of the bacterial disulfide bond (DSB) system. In Gram-negative bacteria, DsbE resides in the periplasm and is typically directed there by a Sec-type signal sequence. It belongs to the Dsb family of redox proteins that orchestrate the formation, maintenance, and rearrangement of disulfide bonds in exported and membrane-associated proteins.

Functionally, DsbE participates in the oxidative folding pathway by participating in disulfide exchange reactions within the periplasm. It is generally thought to operate in conjunction with DsbD, which supplies reducing equivalents to periplasmic proteins, helping to maintain the appropriate redox balance for disulfide bond formation. The exact substrates and roles of DsbE can vary between species, and in some taxa DsbE may have overlapping or subsidiary functions with other Dsb proteins such as DsbC or DsbG.

Structure and organization are characteristic of DsbE proteins: they are small, soluble periplasmic proteins with a thioredoxin-like fold that enables disulfide exchange. The dsbE gene is typically located within the dsb gene cluster and is subject to regulation by cellular redox conditions and environmental stress. The protein is synthesized with a signal peptide for periplasmic localization.

Distribution and significance: DsbE is found in many Gram-negative bacteria, including Escherichia coli and related enterobacteria. It contributes to the proper folding of numerous periplasmic and secreted proteins, and in some pathogens it influences virulence factor maturation. Mutations in dsbE can impair extracellular protein maturation and affect bacterial fitness.

See also: DsbA, DsbB, DsbC, DsbD, DsbG.