Selenylation

Selenylation is a post-translational modification process in which a selenocysteine residue is added to a protein. This modification is catalyzed by selenocysteine lyases, which cleave a selenocysteine-containing precursor protein to release the mature protein and a selenocysteine-containing peptide. The selenocysteine residue is then transferred to a target protein, typically via a trans-selenylation reaction. Selenylation is a reversible process, and the selenocysteine residue can be removed from the protein by selenocysteine deselenases.

Selenylation plays a crucial role in various biological processes, including redox regulation, signal transduction, and protein-protein interactions. Selenocysteine-containing proteins are found in all kingdoms of life, from bacteria to humans, and are involved in a wide range of functions, such as antioxidant defense, enzyme catalysis, and gene regulation.

The selenylation process is highly specific and regulated, with selenocysteine lyases and deselenases playing key roles in controlling the levels of selenocysteine-containing proteins. Mutations in these enzymes have been linked to various diseases, including cancer, neurodegenerative disorders, and metabolic diseases. Understanding the mechanisms of selenylation and its regulation is therefore an active area of research in the field of molecular biology and biochemistry.