Selenium and Selenocysteine in Protein Chemistry

Selenocysteine, the selenium‐containing analogue of cysteine, is the twenty‐first proteinogenic amino acid. Since its discovery almost fifty years ago, it has been exploited in unnatural systems even more often than in natural systems. Selenocysteine chemistry has attracted the attention of many chemists in the field of chemical biology owing to its high reactivity and resulting potential for various applications such as chemical modification, chemical protein (semi)synthesis, and protein folding, to name a few. In this Minireview, we will focus on the chemistry of selenium and selenocysteine and their utility in protein chemistry. Se how far we've come: Since its presence in proteins was discovered over 40 years ago, the singular properties of selenocysteine (Sec) have been exploited by protein chemists for a host of different applications. This Minireview summarizes the use of selenium and selenocysteine in various protein chemistry applications, including chemical modifications, protein synthesis, and protein folding.