Interferon disulfide bonds

Proteins that contain multiple cysteines are difficult to refold after high-level production in E. coli because of the formation of incorrect disulfide bonds. Replacement of individual cysteines or specific disulfide bonding pairs without compromising the functional activity of the protein can result in increased yield of the correctly folded protein. This technique has been applied successfully to interleukin-2 (IL-2 Wang et al, 1984), human fibroblast interferon (Mark et al, 1984), and basic fibroblast growth factor (b-FGF Rinas et al, 1992). 

Similarly, human fibroblast interferon p contains three cysteines at positions 17, 31, and 141. Of these, cysteines at positions 31 and 141 appear to be involved in a disulfide bridge, and are required for antiviral activity of the molecule. Replacement of the free cysteine residue at position 17 with serine resulted in a 10-fold increase in the specific activity of interferon p expressed and purified from E. coU, which also showed improved stability during storage. These improvements are attributed to elimination of intermolecular aggregation and incorrect disulfide bonds caused by the free cysteine 17 (Mark et al, 1984). 

Knight, E., Jr. Fathey, D. Human fibroblast interferon an improved purification. J. Biol. Chem. 1981,256, 3609-3611. Wells, J.A. Powers, D.B. In vivo formation and stability of engineered disulfide bonds in subtilisin. J. Biol. Chem. 1986, 261, 6564-6570. 

Gunther G, Fechteler X, Villmann C, et al. Computer-aided modeling of structure stabilizing disulfide bonds in recombinant human interferon-gamma. Pharm Acta Helv 1996 71 37-44. 

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