Recombinant E. coli DsbG protein

DsbG is a periplasmic disulfide isomerase and reductase primarily found in *Escherichia coli* and related Gram-negative bacteria. It belongs to the Dsb (disulfide bond) protein family, which plays critical roles in catalyzing and rearranging disulfide bonds during oxidative protein folding in the bacterial periplasm. While DsbA, a primary oxidoreductase, introduces disulfide bonds into nascent proteins, DsbG functions as a proofreading enzyme that corrects non-native or misfolded disulfides, particularly under stress conditions. This functional duality ensures proper folding and stability of secreted or membrane-associated proteins, including virulence factors and enzymes.

Structurally, DsbG shares a thioredoxin-like fold with a conserved CXXC active-site motif, similar to other Dsb proteins. However, its unique hydrophobic substrate-binding groove and redox potential (−149 mV) distinguish it from the more oxidizing DsbA (−122 mV). This redox property allows DsbG to act as a reductase or isomerase, reducing or rearranging incorrect disulfide bonds. Additionally, DsbG contributes to bacterial oxidative stress defense by maintaining periplasmic redox homeostasis, interacting with substrates like misfolded proteins or toxic compounds.

Recombinant DsbG is engineered for biotechnological and pharmaceutical applications. By expressing the *dsbG* gene in heterologous systems (e.g., *E. coli*), researchers produce purified DsbG to study its mechanisms or exploit its chaperone-like activity. Its ability to enhance yields of properly folded disulfide-rich proteins—such as antibodies, cytokines, or industrial enzymes—makes it valuable in protein production pipelines. Furthermore, DsbG homologs or engineered variants are explored for improving recombinant protein solubility and stability, addressing challenges in therapeutic protein manufacturing.

Studies on DsbG also provide insights into bacterial pathogenesis, as its dysfunction compromises virulence factor assembly. Inhibiting DsbG could represent a novel antibacterial strategy, though this remains exploratory. Overall, DsbG exemplifies the intersection of fundamental redox biochemistry and applied biotechnology, bridging microbial physiology with industrial protein engineering needs.