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Cysteine sulfenic Acid as an Intermediate in Disulfide Bond Formation and Nonenzymatic Protein Folding

2010; American Chemical Society; Volume: 49; Issue: 35 Linguagem: Inglês

10.1021/bi1008694

1943-295X

Douglas S. Rehder, Chad R. Borges,

Enzyme Structure and Function

As a posttranslational protein modification, cysteine sulfenic acid (Cys-SOH) is well established as an oxidative stress-induced mediator of enzyme function and redox signaling. Data presented herein show that protein Cys-SOH forms spontaneously in air-exposed aqueous solutions of unfolded (disulfide-reduced) protein in the absence of added oxidizing reagents, mediating the oxidative disulfide bond formation process key to in vitro, nonenzymatic protein folding. Molecular oxygen (O(2)) and trace metals [e.g., copper(II)] are shown to be important reagents in the oxidative refolding process. Cys-SOH is also shown to play a role in spontaneous disulfide-based dimerization of peptide molecules containing free cysteine residues. In total, the data presented expose a chemically ubiquitous role for Cys-SOH in solutions of free cysteine-containing protein exposed to air.