Computational design of a red fluorophore ligase for site-specific protein labeling in living cells

This work establishes a fluorescence labeling method that can be used in living cells to derivatize specific proteins of interest with a small red fluorophore, resorufin. The method has extremely high sequence specificity and is based on a computationally designed fluorophore ligase, derived from Escherichia coli lipoic acid ligase. These results demonstrate the power of computational design to majorly reengineer enzyme specificity. Extensive screening of rationally designed enzyme mutants failed to achieve the same result.