title: 8-Fluoro-8-demethylriboflavin as a 19F-probe for flavin-protein interaction. A 19F NMR study with egg white riboflavin binding protein.
abstract: Binding of 8-fluoro-8-demethylriboflavin to riboflavin binding protein was studied 19F-NMR spectroscopically. The pH dependence of 19F chemical shift of this fluoro derivative both free and bound to the protein revealed a shift of pKa associated with N(3)-H to alkali when bound to the protein. 19F chemical shift of the fluoro derivative bound to the protein is in a higher magnetic field than that of the free derivative in the neutral to acidic pH region. These results are interpreted in terms of the environmental changes at the 8- and 3-positions of isoalloxazine, indicating the applicability of this derivative for probing flavin-protein interaction at these positions.
mesh_terms: D002352:Carrier Proteins / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D004529:Egg White / Q000032:analysis*; D005461:Fluorine; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D026901:Membrane Transport Proteins; D011485:Protein Binding; D012256:Riboflavin / Q000031:analogs & derivatives*
chemical_list: D002352:Carrier Proteins; D026901:Membrane Transport Proteins; C019079:riboflavin-binding protein; C037198:8-fluoro-8-demethylriboflavin; D005461:Fluorine; D012256:Riboflavin