Abstract
NO is a versatile free radical that mediates numerous biological functions within every major organ system. A molecular pathway by which NO accomplishes functional diversity is the selective modification of protein cysteine residues to form S-nitrosocysteine. This post-translational modification, S-nitrosylation, impacts protein function, stability, and location. Despite considerable advances with individual proteins, the in vivo biological chemistry, the structural elements that govern the selective S-nitrosylation of cysteine residues, and the potential overlap with other redox modifications are unknown. In this minireview, we explore the functional features of S-nitrosylation at the proteome level and the structural diversity of endogenously modified residues, and we discuss the potential overlap and complementation that may exist with other cysteine modifications.