Expanding the functional diversity of proteins through cysteine oxidation

The polarizable sulfur atom in cysteine is subject to numerous post-translational oxidative modifications in the cellular milieu, which regulates a wide variety of biological phenomena such as catalysis, metal binding, protein turnover, and signal transduction. The application of chemical rationale to describe the features of different cysteine oxoforms affords a unique perspective on this rapidly expanding field. Moreover, a chemical framework broadens our understanding of the functional roles that specific cysteine oxidation states can play and facilitates the development of mechanistic proposals, which can be tested in both biochemical and cellular studies.