Protein splicing: A versatile tool for drug discovery.

The judicious application of intein technologies to biological problems has resulted in powerful tools for biomedical research. Inteins are intervening sequences that excise themselves from precursor proteins and ligate the surrounding sequences. Variations of intein chemistry have been used to create tagless protein purification strategies, specifically label expressed proteins for biochemical assays, design biosensors, produce microarrays, and synthesize cyclic peptide libraries for inhibitor studies. Moreover, recent advances in small molecule triggered protein splicing allow for tunable post-translational control of protein function in vivo. Inteins are now positioned as an essential tool to study the mechanism of disease progression and validate drug candidates. Yet these tiny proteins have more tricks to play. Recent progress in gene therapy and drug targeting suggest a bright future where split inteins mediate in vivo reconstruction of large therapeutic proteins and target drugs to a specified site of action. Inteins are rapidly becoming valuable tools for drug discovery and drug delivery.