Rhodobacter sphaeroides photosynthetic reaction center

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 ... 

Grafton, A. K. Wheeler, R. A. "Amino Acid Protonation States Determine Binding Sites of the Secondary Ubiquinone and its Anion in the Rhodobacter sphaeroides Photosynthetic Reaction Center,"/ Phys. Chem. B1999,103,5380-5387. 

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

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... 

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... 

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],... 

Chang, C. H., El Kabbani, O., Tiede, D., Norris, J., and Schiffer, M., 1991, Structure of the membrane-bound protein photosynthetic reaction center from Rhodobacter sphaeroides. Biochemistry, 30 5352115360. 

Chirino, A. J., Lous, E. J., Huber, M., Allen, J. P., Schenck, C. C., Paddock, M. L., Feher, G., and Rees, D. C., 1994, Crystallographic analyses of site-directed mutants of the photosynthetic reaction center from Rhodobacter sphaeroides. Biochemistry, 33 458494593. 

Van Brederode, M. E., Jones, M. R., and Van Grondelle, R., 1997a, Fluorescence excitation spech a of membrane bound photosynthetic reaction centers of Rhodobacter sphaeroides in which tyrosine M210 is replaced by byptophan evidence for a new pathway of charge separation. Chem. Phys. Letts., 268 143nl49. 

Zinth, W., and Kaiser, W., 1993, Time-resolved spectroscopy of the primary electron transfer in reaction centers of Rhodobacter sphaeroides and Rhodopseudomonas viridis. In The Photosynthetic Reaction Center, (J. Deisenhofer and J. R. Norris, eds.) Volume 2, 71988, Academic Press, San Diego, USA. 

The formation of a hydrogen bond between the amide proton and one carbonyl oxygen of NQ was indicated in the Ec + —NQ /M" complex to stabilize the complex (see above). Electron-transfer reactions were believed to be regulated through such noncovalent interactions that play an important role in biological ET systems, where electron donors and acceptors are usually bound to proteins at a fixed distance (123-127). Eor example, in the bacterial photosynthetic reaction center (bRC) from Rhodobacter Rb) sphaeroides, an electron is transferred from... 

Figure 14 Structure of the photosynthetic reaction center from Rhodobacter sphaeroides in the region of the Fe + and quinones. The residue numbers refer to the L and M subunits of the reaction center...

Bacterial photosynthetic reaction centers (PRC) have been among the most actively studied ET proteins since DeVault and Chance first measured C. vinosum tunneling rates in the early 1960s. In many cases, measurements of ET kinetics preceded determination of the three-dimensional structure of the membrane-bound protein assembly. It was not until the X-ray crystal-stracture determinations of the Rhodopseudomonas (Rps.) viridus and Rhodobacter (Rb.) sphaeroides PRCs that distances could be assigned to specific rate constants. The recent crystal structures of photosystems l and from cyanobacteria promise to clarify critical aspects of the ET mechanisms in oxygenic PRC. ... 

Figure 4 Proton transfer pathway in the photosynthetic reaction center from Rhodobacter sphaeroides connects the soivent-exposed part of the protein (Hisl 26-Hisl 28) to the secondary quinone binding site Qg (6).

Figure I. The arrangement of the chromophores, electron donors, and electron acceptors in the photosynthetic reaction center of the bacterium Rhodobacter sphaeroides [8], The double horizontal lines at the top and bottom of the figure show the approximate location of the surfaces of the lipid bilayer membrane.

Fig. 8. Three-dimensional structure of the photosynthetic reaction center of Rb. sphaeroides R-26. The a-helices are drawn as columns. Modified from the original color drawing of Allen, Feher, Yeates, Komiya and Rees (1987) Structure of the reaction center from Rhodobacter sphaeroides R-2. The protein subunits. Proc Nat Acad Sci, USA, 84 6165.

Fig. 9. (A) Absorption spectrum of Rb. sphaeroides used as a reference to show the Qx and Qy bands of the primary donor (P), BChl [B] and bacteriopheophytin [BO] (B) Femtosecond absorption changes at 920 (a), 785 (b) and 545 nm (c) vs. the delay time of the monitoring pulse measured at room temperature, and (C) absorption changes at 920 (a) and 794 nm (b) measured at 25 K. Figure source (A) see Fig. 7 (B) Holzapfel, Finkele, Kaiser, Oesterheldt, Scheer, Stilz and Zinth (1990) Initial electron transferin the reaction center from Rhodobacter sphaeroides. Proc Nat Acad Sci, USA 87 5170 (C) Zinth and Kaiser (1993) Time-resolved spectroscopy of the primary electron transfer in reaction centers of Rhodobacter sphaeroides and Rhodopseudomonas viridis. I n JR Norris and J Deisenhofer (eds) The Photosynthetic Reaction Center, Voi il, p 82. Acad Press.

C Lautwasser, U Finkele, H Scheer and WZinth (1991) Temperature dependence of the primary electron transfers photosynthetic reaction centers from Rhodobacter sphaeroides. Chem Phys Lett 183 471-477... 

Hughes JM, Hutter MC, Reimers JR, Hush NS. Modeling the bacterial photosynthetic reaction center. 4. The structural, electrochemical, and hydrogen-bonding properties of 22 mutants of Rhodobacter sphaeroides. J Am Chem Soc 2001 123 8550-8563. 

P. Beroza, D. R. Fredkin, M. Y. Okamura, and G. Feher, Proc. Natl. Acad. Sci. U.S.A., 88, 5804 (1991). Protonation of Interacting Residues in a Protein by a Monte Carlo Method Application to Lysozyme and the Photosynthetic Reaction Center of Rhodobacter sphaeroides. 

Figure 2. Arrangement of the electron transfer cofactors in the photosynthetic reaction center protein from the bacterium Rhodobacter sphaeroides. The figure shows the special pair of bacteriochlorophylls (top, in green and light blue), two accessory bacteriochlorophyll molecules (dark blue), two bacteriopheophytins (red), the primary quinone (Qa), the secondary quinone (Qb), and the non-heme iron.

Walden, S. E. Wheeler, R. A. "Protein Conformational Gate Controlling Binding Site Preference and Migration of Ubiquinone-B in the Photosynthetic Reaction Center of Rhodobacter sphaeroides,"J. Phys. Chem. B 2002, 106, 3001-3006. 

Adir N, Axelrod HL, Beroza P, Isaacson RA, Rongey SH, Okamura MY and Feher G (1996) Co-crystallization and characterization of the photosynthetic reaction center cytochrome c-2 complex from Rhodobacter sphaeroides. Biochemistry 35 2535-2547... 

Stilz HU, Finkele U, Holzapfel W, Lauterwasser C, Zinth W and Oesterhelt D (1994) Influence ofM subunit Thr222 and Trp252 on quinone binding and electron transfer in Rhodobacter sphaeroides reaction centres. Eur J Biochem 223 233-242 Stowell MHB, McPhillips TM, Rees DC, Soltis SM, Abresch E and Feher G (1997) Light-induced structural changes in photosynthetic reaction center Implications for mechanism of electron-proton transfer. Science 276 812-816 Takahashi E and Wraight CA (1996) Potentiation of proton transfer function by electrostatic interactions in photosynthetic reaction centers from Rhodobacter sphaeroides First results... 

Arnoux B, Ducruix A, Reiss-Husson F, LutzM, Norris J, Schiffer M and Chang C-H (1989) Structure of spheroidene in the photosynthetic reaction center from Y Rhodobacter sphaeroides. FEBS Lett 258 47-50... 

NMR evidence for a 15,15 -cis configuration of the spheroidene in the Rhodobacter sphaeroides photosynthetic bacterial reaction center. Biochemistry 31 12446-12450... 

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