Isolation of a Se-nitrososelenol: a new class of reactive nitrogen species relevant to protein Se-nitrosation.

Nitric oxide (NO) is a messenger molecule implicated in a number of physiological processes. Nitrosation of selenoproteins has been suggested as playing an important role in NO-mediated cellular functions such as the inactivation of glutathione peroxidase (GPx), but no chemical information about Se-nitrosated species has been available to date. Here a stable Se-nitrososelenol (RSeNO), a new class of NO derivative, was synthesized and fully characterized by X-ray crystallography and spectroscopic methods. This Se-nitrososelenol can be formed by direct transnitrosation from an S-nitrosothiol to a selenol, as is the case in the proposed mechanism for the NO-mediated inactivation of GPx.