SNitrosylierung

S-Nitrosylation is a post-translational modification of proteins that involves the transfer of a nitrosyl group (NO+) from a nitrosating agent to a thiol group (-SH) of a cysteine residue in a protein. This modification is catalyzed by enzymes called S-nitrosyltransferases (SNTs) and can be reversed by S-nitrosoglutathione reductases (GSNRs).

The nitrosyl group is a reactive intermediate that can modify various biological targets, including proteins, lipids, and nucleic acids. In the context of proteins, S-nitrosylation can alter their structure, function, and stability. It has been implicated in a wide range of physiological processes, such as vasodilation, neurotransmission, and immune response.

S-nitrosylation can occur endogenously through the reaction of nitric oxide (NO) with cysteine residues in proteins, or it can be induced exogenously by treating cells with nitrosating agents like S-nitroso-N-acetylpenicillamine (SNAP) or 3-morpholinosydnonimine (SIN-1). This modification can have both beneficial and detrimental effects, depending on the context. For example, S-nitrosylation of soluble guanylyl cyclase (sGC) by NO leads to the activation of cyclic guanosine monophosphate (cGMP) production, which relaxes smooth muscle cells and promotes vasodilation. However, excessive S-nitrosylation can also lead to protein aggregation, oxidative stress, and cellular damage.

The study of S-nitrosylation has important implications for understanding various diseases and developing therapeutic strategies. For instance, dysregulation of S-nitrosylation has been linked to conditions such as hypertension, neurodegenerative diseases, and inflammation. Targeting S-nitrosylation pathways may therefore offer novel approaches for treating these disorders.