An Engineered Aryl Azide Ligase for Site‐Specific Mapping of Protein–Protein Interactions through Photo‐Cross‐Linking

Abstract
Labeled and linked: The small‐molecule binding site of Escherichia coli lipoic acid ligase was re‐engineered to accept a fluorinated aryl azide probe in place of lipoic acid. Labeling with this mutant is highly specific for LAP fusion proteins. In cell lysate, FK506 binding protein was labeled and rapamycin‐dependent photo‐cross‐linking to its interaction partner was demonstrated.