FTIR Characterization of Leu M160→His, Leu L131→His and His L168→Phe Mutations Near the Primary Electron Donor in RB. Sphaeroides Reaction Centers

摘要: Light-induced FTIR difference spectroscopy has been used to monitor structural changes in Rb. sphaeroides mutant reaction centers (RCs) associated with the substitution of amino acids near primary electron donor (P). In wild type RC, 9keto carbonyls for both BChls constituting P (PL and PM) have no specific interactions protein. A hydrogen bond probably exists between 2a acetyl C=O PL His L1681,2 but such is possible symmetry related acid on M side, a Phe residue (M197). The mutations Leu L131→His M160→His3 (see also Williams et al., these proceedings) were designed introduce proton donating that could form keto ring V each BChl dimer. addition, mutation L168→Phe was break L168.