CHAPTER 3.1: Disulfide Bond Formation and Isomerization in Escherichia coli

Structural disulfide bonds are a typical feature of secretory proteins that are often required for protein folding and stability. Formation of a disulfide bond from a cysteine pair in a newly synthesized protein is a redox reaction that requires the interaction of the folding protein with an oxidant that accepts the two electrons generated. As the redox environment in the cellular cytoplasm is reducing, structural disulfide bonds are essentially formed only in oxidizing compartments of the secretory pathway, namely the periplasmic space in bacteria and the endoplasmic reticulum in eukaryotic cells. This chapter focuses on the mechanisms underlying the oxidative folding of proteins in the periplasm of Gram-negative bacteria, where more than half of the periplasmic and outer membrane proteins contain at least one structural disulfide bond.