Rhodobacter sphaeroides center

Prisner T F, van der Est A, BittI R, Lubitz W, Stehlik D and Mdbius K 1995 Time-resolved W-band (95 GHz) EPR spectroscopy of Zn-substituted reaction centers of Rhodobacter sphaeroides R-26 Chem. Phys. 194 361-70... 

Vos M H, Jones M R, Breton J, Lambry J-C and Martin J-L 1996 Vibrational dephasing of long- and short-lived primary donor states in mutant reaction centers ot Rhodobacter sphaeroides Biochemistry 35 2687-92... 

Wynne K, Haran G, Reid G D, Moser 0 0, Dutton P L and Hochstrasser R M 1996 Femtosecond infrared spectroscopy of low-lying excited states in reaction centers of Rhodobacter sphaeroides J. Rhys. Chem. 100 5140-8... 

Figure 12.23 Hydropathy plots for the polypeptide chains L and M of the reaction center of Rhodobacter sphaeroides. A window of 19 amino acids was used with the hydrophohicity scales of Kyte and Doolittle. The hydropathy index is plotted against the tenth amino acid of the window. The positions of the transmembrane helices as found by subsequent x-ray analysis by the group of G. Feher, La Jolla, California, ate indicated by the green regions.

Table 12.2 Amino acid sequences of the transmembrane helices of the photosynthetic reaction center in Rhodobacter sphaeroides...

Allen, J.R, et al. Structure of the reaction center from Rhodobacter sphaeroides R-26 the cofactors. Proc. Natl. Acad. Sd. USA 84 5730-5734, 1987. 

Photosynthetic reaction centers from Rhodobacter sphaeroides and bacteri-orhodopsin (BR) from purple membrane (PM) have been used for their unique optoelectronic properties and for their capability of providing light-induced proton and electron pumping. Once assembled they display extremely high thermal and temporal stability... 

Burghaus, O., M. Plato et al. (1991). 3mm EPR investigation of the primary donor cation radical in single crystals of Rhodobacter sphaeroides R-26 reaction centers. Chem. Phys. Lett. 185 381-386. 

Ishikita, H. Morra, G. Knapp, E.W., Redox potential of quinones in photosynthetic reaction centers from Rhodobacter sphaeroides dependence on protonation of Glu-L212 and Asp-L213, Biochemistry 2003, 42, 3882-3892... 

Brederode ME, Jones MR, Van Grondelle R (1997) Primary electron transfer kinetics in membrane-bound Rhodobacter sphaeroides reaction centers a global and target analysis. 

There have been few studies to date of the functionality and stability of AP-trapped photosynthetic reaction centers. Rhodobacter sphaeroides reaction centers were shown to remain intact following trapping with AP A8-75 (a more highly charged analog of A8-35), but neither their functionality nor their stability over time were studied[5]. Synechocystis PCC 6803 PS1 reaction centers trapped with A8-35 and deposited on a gold electrode have been shown to be electrochemically active, but their long-term stability has not been studied[12]. The photochemical activity of A8-35-trapped pea PS2 reaction centers, measured at room temperature by the accumulation of the pheophytin free radical upon illumination, was found to be intermediate between that in chaps and in P-DM solutions [A. Zehetner H. Scheer, personal communication ref. 13],... 

It is evident that the preceding considerations do not apply to all biological electron transfer systems. Even in the bacterial reaction center, the transfer between the two quinones Qa Qbj which takes place over 18 A [18], is characterized in Rhodobacter sphaeroides by a large entropic contribution, which has been attributed to the high solvent exposure of Qg [126]. By using the activation energy value reported in Ref. [126], two very different X values may be deduced from Eq. (23) = 0.1 eV and Aj = 2.5 eV. The previous considerations... 

Study the AG° dependence at different temperatures. This was done by Dutton and co-workers for the electron transfers from Bph to and Qa to (Bchl)2 in Rhodobacter sphaeroides photosynthetic reaction centers [139,140], which take place over about 13 A and 25 A, respectively [18], The rates were measured between 10 K and 300 K in series in which quinone substitutions provide AG° ranges of 0.5 eV and 0.8 eV for the two reactions respectively. The following conclusions were deduced from a thorough analysis of the experimental results ... 

The recent X-ray crystallographic determination of the structure of Rhodopseu-domonas viridis [15-17] and Rhodobacter sphaeroides [18-20] reaction centers has been the starting point of many theoretical studies. This structure, which is represented in Fig. 4 has confirmed the arrangement of the co-factors that had... 

On the planet Earth, the most important photoreaction occurs in green plants or in green or purple organisms. Their photochemical reaction centers contain a special pair of chlorins (cf. the purple bacterium Rhodobacter sphaeroides. Fig. 6.2). Solar photons cause electron transfer and generate a radical ion pair. Within two picoseconds, the negative charge is transferred to a second chlorin, and from it to a quinone. ... 

The reduction of DMSO catalyzed by molybdenum is an important step in the process of anaerobic respiration carried out by a number of bacteria (169). Much like sulfite oxidase, early MCD studies of DMSO reductase were complicated by the presence of heme iron (173). The discovery of two enzymes that do not include an iron center led to the measurement of MCD spectra of Rhodobacter sphaeroides DMSO reductase that could be assigned exclusively in terms of transitions of the Mo site (Fig. 10b) (174). The six major peaks are assigned as LMCT transitions from the three highest energy occupied orbitals to the two lowest unoccupied orbitals (174). 

The three-dimensional structures of the reaction centers of purple bacteria (Rhodopseudomonas viridis and Rhodobacter sphaeroides), deduced from x-ray crystallography, shed light on how phototransduction takes place in a pheophytin-quinone reaction center. The R. viridis reaction center (Fig. 19-48a) is a large protein complex containing four polypeptide subunits and 13 cofactors two pairs of bacterial chlorophylls, a pair of pheophytins, two quinones, a nonheme iron, and four hemes in the associated c-type cytochrome. 

The crystal structure of reaction centers from R. viridis was determined by Hartmut Michel, Johann Deisenhofer, Robert Huber, and their colleagues in 1984. This was the first high-resolution crystal structure to be obtained for an integral membrane protein. Reaction centers from another species, Rhodobacter sphaeroides, subsequently proved to have a similar structure. In both species, the bacteriochlorophyll and bacteriopheophytin, the iron atom and the quinones are all on two of the polypeptides, which are folded into a series of a helices that pass back and forth across the cell membrane (fig. 15.1 la). The third polypeptide resides largely on the cytoplasmic side of the membrane, but it also has one transmembrane a helix. The cytochrome subunit of the reaction center in R. viridis sits on the external (periplasmic) surface of the membrane. 

Paddock, M.L., S.H. Rongey, E.C. Abresch, G. Feher, and M.Y. Okamura (1988). Reaction centers from three herbicide-resistant mutants of Rhodobacter-sphaeroides 2,4,1 sequence analysis and preliminary characterization. Photosyn. Res., 17 75-96. 

Fig. I. Arrangement of the chromophores, electron donors, and electron acceptors in the bacterial reaction center of Rhodobacter sphaeroides [2f], The horizontal lines at the top and bottom of the figure represent the approximate location of the surfaces of the lipid bilayer membrane...

Groot ML, Yu JY, Agarwal R, Norris JR, Fleming GR. Three-pulse photon echo experiments on the accessory pigment in the reaction center of Rhodobacter sphaeroides. J Phys Chem B 1998 102 5923-5931. 

Nabedryk, E., Breton, J., Okamura, M.Y., and Paddock, M. L. (2001) Simultaneous replacement of Asp-L210 and Asp-M17 with Asn increases proton uptake by Glu-L212 upon first electron transfer to Qb in reaction centers from Rhodobacter sphaeroides, Biochemistry 40, 13826-13832. 

Solovev AA, Katz E, Shuvalov VA, Erokhin YE (1991) Photoelectrochemical effects for chemically modified platinum electrodes with immobilized reaction centers for Rhodobacter sphaeroides R-26. Bioelectrochem Bioenerg 26 29-41... 

Gunner, M. R. (1988). The temperature and — AG dependence of long range electron transfer in reaction center protein from Rhodobacter sphaeroides. U niv. of Pennsylvania, Philadelphia. 

Gunner, M. R., and Dutton, P. L., 1989, Temperature and -Delta-G-Degrees Dependence of the Electron-Transfer from Bph.- to Qa in Reaction Center Protein from Rhodobacter-Sphaeroides with Different Quinones As Qa J. Amer. Chem. Soc. Ill 3400n3412. 

Labahn, A., Paddock, M. L., McPherson, P. H., Okamura, M. Y., and Feher, G., 1994, Direct Charge Recombination from D+QAQB- to DQAQB in Bacterial Reaction Centers from Rhodobacter sphaeroides J. Chem. Phys. 98 341733423. 

Li, J. L., Gilroy, D., Tiede, D. M., and Gunner, M. R., 1998, Kinetic phases in the electron transfer from P+QA-QB to P+QAQB- and the associated processes in Rhodobacter sphaeroides R-26 reaction centers Biochemistry 37 2818n2829. 

Lin, X., Williams, J. C., Allen, J. P., and Mathis, P., 1994, Relationship between rate and free-energy difference for electron-transfer from cytochrome c(2) to the reaction center in Rhodobacter sphaeroides Biochemistry 33 13517913523. 

FIGURE 9. The structure of DMSO reductase from Rhodobacter sphaeroides (Schindelin et al., 1994). The four domains referred to in the text are indicated. The molybdenum center is rendered in wireframe representation. 

Britt, R. D., Sauer, K., Klein, M. P., Knaff, D. B., Kriauciunas, A., Yu, C. A., Yu, L., and Malkin, R., 1991, Electron spin echo envelope modulation spectroscopy supports the suggested coordination of two histidine ligands to the Rieske Fe-S centers of the cytochrome b6f complex of spinach and the cytochrome bcl complexes of Rhodospirillum rubrum, Rhodobacter sphaeroides, and bovine heart mitochondria. Biochemistry 30 1892nl901. 

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