Conformational stability of disulfide bonds in redox processes

The protein sulfur functions have numerous cellular fundamental roles. They are in charge of the maintenance of the cellular reduction potential, which in turn governs gene expression. In addition, the redox cycling of disulfide/thiol functions has a great importance in the protein folding-unfolding process, which governs the functioning of enzymes. In our previous studies, we showed that the redox properties of disulfide bonds differ considerably. An analysis of the structure of the disulfide bonds in several proteins in the Protein Data Bank indicated that there are two types of conformations. Thus, we have compared the structures of the anions in these two types of conformation and the SS bond dissociation energy of the anion. For both conformations, the SS bond length of the anion and the electronic affinity are very close. However, the bond dissociation energy (BDE) varies.