Rhodopseudomonas viridis, reaction center

MR Gunner, B Homg. Electrostatic control of midpoint potentials m the cytochrome subunit of the Rhodopseudomonas viridis reaction center. Proc Natl Acad Sci USA 88 9151-9155, 1991. 

MR Gunner, A Nicholls, B Honig. Electrostatic potentials in Rhodopseudomonas viridis reaction centers Implications for the driving force and directionality of electron transfer. J Phys Chem 100 4277-4291, 1996. 

Arlt, T., Dohse, B., Schmidt, S., Wachtveitl, J., Laussermair, E., Zinth, W., and Oesterhelt, D., 1996, Electron transfer dynamics of Rhodopseudomonas viridis reaction centers with a modified binding site for the accessory bacteriochlorophyll. Biochemistry, 35 92359 9244. 

Gunner, M. R. and B. Honig. (1991). Electrostatic Control of Midpoint Potentials in the Cytochrome Subunit of the Rhodopseudomonas Viridis Reaction Center. Proc. Natl. Acad. Sci. USA. 88 9151-9155. 

Fig. 2. Absorption spectra of BChl a in petroleum ether and the Rb. sphaeroides R-26 reaction-center preparation (A) and of BChl b in ether and in the BChl b-containing Rhodopseudomonas viridis reaction-center preparation (B). Figure source (A) Reed and Peters (1972) Characterization of the pigments in reaction center preparation from Rhodopseudomonas sphaeroides. J Biol Chem 246 7148 (B) Parson, Scherz and Warshel (1985) Calculation of spectroscopic properties of bacterial reaction centers. In ME Michel-Bayerle (ed) Antennas and Reaction Centers of Photosynthetic Bacteria, p 123. Springer Verlag.

Fig. 11. Model of the tetraheme arrangement in the cytochrome subunit in Rp. viridis consistent with available evidence based on spectral, electrochemical and onentational properties of the hemes. Heme orientations adapted from Alegria and Dutton (1991) II. Langmuir-Blodgeti monolayer films of the Rhodopseudomonas viridis reaction center determination of the order of the hemes in the cytochrome c subunit. Biochim Biophys Acta 1057 271.

SM Dracheva, LA Drachev, SM Zaberezhnaya, AA Konstantinov, A Semenov and VP Skuiachev (1986) Spectra/, redox and kinetic characteristics of high-potentiai cytochrome c hemes in Rhodopseudomonas viridis reaction center. FEBS Lett 205 41-46... 

A Vermeglio, P Richaud and J Breton (1989) Orientation and assignment of the four cytochrome hemes in Rhodopseudomonas viridis reaction centers. FEBS Lett 243 259-263... 

LTakiff and SG Boxer (1987) Phosphorescence from the primary electron donor in Rhodobacter sphaeroldes and Rhodopseudomonas viridis reaction centers. Biochim Biophys Acta 932 325-334 L Takiff and SG Boxer (1987) Phosphorescence spectra of bacteriochlorophylls. J Am Chem Soc 110 425-4426... 

Dohse B, Mathis P, WachtveM J, Laussermair E, Iwata S, Michel H and Oesterhelt D (1995) Electron transfer from the tetraheme cytochrome to the special pair in the Rhodopseudomonas viridis reaction center Effects of mutations of tyrosine L162. Biochemistry 34 11335-11343... 

THE THERMODYNAMIC CHARACTERISTIC OF FOUR-HEME CYTOCHROME C FROM RHODOPSEUDOMONAS VIRIDIS REACTION CENTERS... 

The Thermodynamic Characteristic of Four-Heme Cytochrome C from Rhodopseudomonas viridis Reaction Centers 185... 

Recent Advances in the Structure Analysis of Rhodopseudomonas viridis Reaction Center Mutants... 

The photosynthetic reaction center is currently the only membrane protein complex whose structure is known to atomic resolution [15]. Before the three-dimensional structure was actually solved by X-ray diffraction, however, protein hydropathy plots were used to show the existence of a total of 11 transmembrane helices in the three subunits H, L and M by analyzing the deduced amino acid sequence of the reaction center genes [16]. Figure 2 shows the hydropathy plots of the L and M subunits of the Rhodopseudomonas viridis reaction center using a window of 19 residues. The upper trace within each panel is obtained from the semi-empirical amino acid residue hydropathy values [11], and the lower trace is calculated using the nucleotide-determined values from SVD (without translation). Although the plots do not take codon usage or the NGN problem into account, each pair is nevertheless virtually identical (the protein hydropathy has been displaced for display purposes). The A, B, C, D, and E transmembrane helices of each subunit are easily identified as relative maxima. 

By inspection of the x-ray structure of Rhodopseudomonas viridis reaction centers one can recognize that the donor hem and the acceptor... 

ELECTRON TRANSFER IN RHODOPSEUDOMONAS VIRIDIS REACTION CENTERS WITH PREREDUCED BACTERIOPHEOPHYTIN BL... 

FIGURE 118.1 The Rhodopseudomonas viridis reaction center, with approximate half-times of the three major steps of electron transfer on the active acceptor branch, and of one step from the cytochrome moiety (only partly drawn). Membrane thickness about 35 A. (Inspired from Deisenhofer, J. and Michel, H EMBO /., 8, 2149,1989.)... 

FIGURE 118.3 Absorption spectrum of a suspension of Rhodopseudomonas viridis reaction centers (plus 100 pM Na ascorbate) dispersed by a detergent (LDAO). The absorption band at 970 nm is due to the primary donor P, and the large massif around 820 nm is mainly due to the two bacteriochlorophylls other than P, and to the two bacteriopheophytins. (Reaction centers kindly provided by Dr. J. Breton.)... 

FIGURE 118.4 Absorption change at 1283 nm due to the oxidation of P by a flash, followed by its re-reduction by an electron coming from the high-potential heme of the tetraheme cytochrome in Rhodopseudomonas viridis reaction centers, at 287 K, at an ambient redox potential of about +200 mV (see Reference 48). 

---