title: Probing the secondary quinone (QB) environment in photosynthetic bacterial reaction centers by light-induced FTIR difference spectroscopy.
abstract: The photoreduction of the secondary electron acceptor, QB, has been characterized by light-induced Fourier transform infrared difference spectroscopy of Rb. sphaeroides and Rp. viridis reaction centers. The reaction centers were supplemented with ubiquinone (UQ10 or UQ0). The QB- state was generated either by continuous illumination at very low intensity or by single flash in the presence of redox compounds which rapidly reduce the photooxidized primary electron donor P+. This approach yields spectra free from P and P+ contributions making possible the study of the microenvironment of QB and QB-. Assignments are proposed for the C...O vibration of QB- and tentatively for the C = O and C = C vibrations of QB.
authors.affiliation: DBCM/SBE, C.E.N. Saclay, Gif-sur-Yvette, France.
authors.forename: J
authors.initials: J
authors.lastname: Breton
authors.forename: C
authors.initials: C
authors.lastname: Berthomieu
authors.forename: D L
authors.initials: DL
authors.lastname: Thibodeau
authors.forename: E
authors.initials: E
authors.lastname: Nabedryk
mesh_terms: D016227:Benzoquinones / Q000737:chemistry*; D005583:Fourier Analysis; D010084:Oxidation-Reduction; D010775:Photic Stimulation; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D012242:Rhodobacter sphaeroides / Q000032:analysis; D013055:Spectrophotometry, Infrared; D014451:Ubiquinone / Q000737:chemistry
chemical_list: D016227:Benzoquinones; D045322:Photosynthetic Reaction Center Complex Proteins; D014451:Ubiquinone; C004532:quinone