- Escherichia coli SHuffle is a specially engineered strain developed to enhance the correct folding of disulfide bond-containing proteins in the bacterial cytoplasm.
- In wild-type E. coli, the cytoplasm is a reducing environment, which prevents the formation of disulfide bonds—an essential structural feature of many eukaryotic proteins, especially those secreted or membrane-bound.
- SHuffle strains overcome this limitation by disrupting the thioredoxin reductase (trxB) and glutathione reductase (gor) genes, creating a more oxidizing cytoplasmic environment that favors disulfide bond formation.
- To further improve disulfide bond isomerization and proper folding, SHuffle strains also express a cytoplasmic version of DsbC, a disulfide bond isomerase usually found in the periplasm. This enzyme helps correct mispaired disulfide bonds, increasing the yield of properly folded, functional protein.
- The strain is often based on BL21(DE3), allowing it to be used with T7 promoter-based expression systems like the pET series, and is typically available in versions with or without the pLysS plasmid for tighter control of basal expression.
- SHuffle is especially valuable for the expression of antibodies, cytokines, growth factors, and other disulfide-rich proteins that are typically difficult or impossible to express functionally in standard E. coli strains. While expression levels may be lower than in conventional strains like BL21(DE3), the trade-off is significantly improved folding and solubility for these challenging proteins.
- As such, E. coli SHuffle is an important tool for biotechnologists and structural biologists working with complex, disulfide-bonded proteins in prokaryotic systems.
