Recent Developments in Metal-Catalyzed Bio-orthogonal Reactions for Biomolecule Tagging.

With the rapid advances in single-molecule and live-cell imaging studies to investigate biological problems, the role of chemical probes to monitor reactions in a live cell has considerably increased. However, selective labeling of a target protein or a specific residue is highly challenging due to the high complexity of the biological system. In particular, biological macromolecules (such as proteins, DNA, or RNA) share many functional groups that potentially cross-react with exogenous chemical probes. Thus, there are high demands for perfect biocompatible reactions utilizing biologically unavailable chemistry. Metal-catalyzed reactions have been extensively investigated as synthetic methodology studies, including initial attempts in applying the chemistry in aqueous solutions in vitro or even in biological conditions. Herein, the latest developments and progress in metal-catalyzed bio-orthogonal reactions for biomolecule labeling are summarized.