Protein desulfurization and deselenization.

Methods enabling the dechalcogenation of thiols or selenols have been investigated and developed for a long time in fields of research as diverse as the study of prebiotic chemistry, the engineering of fuel processing techniques, the study of biomolecule structures and function or the chemical synthesis of biomolecules. The dechalcogenation of thiol or selenol amino acids is nowadays a particularly flourishing area of research for being a pillar of modern chemical protein synthesis, when used in combination with thiol or selenol-based chemoselective peptide ligation chemistries. This review offers a comprehensive and scholarly overview of the field, emphasizing emerging trends and providing a detailed and critical mechanistic discussion of the dechalcogenation methods developed so far.

Electrostatic Assistance of 4-Mercaptophenylacetic Acid-Catalyzed Native Chemical Ligation.

4-Mercaptophenylacetic acid (MPAA) is a popular catalyst of the native chemical ligation (NCL) but has to be used in large excess for achieving practically useful rates (up to 50-100 equiv). We report here that the catalytic potency of MPAA can be boosted by introducing a stretch of arginines in the departing thiol from the thioester. By doing so, the electrostatically assisted NCL reaction proceeds rapidly by using substoichiometric concentrations of MPAA, an advantage that enables useful synthetic applications.