Fluorescent labeling of proteins by fluorophore Prodan is a useful tool to measure protein conformational changes via color switching, however, structure-based rules that predict where to emplace fluorophores that elicit robust fluorescent responses are challenging to establish. Here, the authors investigate mutated glucose-binding proteins labeled with Prodan derivatives, and uncover a mechanism for Prodan ligand-mediated color switching that enables structure-based biosensor design using specific steric interactions between fluorophore and protein.
- Malin J. Allert
- Shivesh Kumar
- Homme W. Hellinga
