Purple bacterium Rhodopseudomonas

Deisenhofer, J., Michael, H. Nobel lecture. The photosynthetic reaction center from the purple bacterium Rhodopseudomonas viridis. EMBO f. 8 2149-2169, 1989. 

What molecular architecture couples the absorption of light energy to rapid electron-transfer events, in turn coupling these e transfers to proton translocations so that ATP synthesis is possible Part of the answer to this question lies in the membrane-associated nature of the photosystems. Membrane proteins have been difficult to study due to their insolubility in the usual aqueous solvents employed in protein biochemistry. A major breakthrough occurred in 1984 when Johann Deisenhofer, Hartmut Michel, and Robert Huber reported the first X-ray crystallographic analysis of a membrane protein. To the great benefit of photosynthesis research, this protein was the reaction center from the photosynthetic purple bacterium Rhodopseudomonas viridis. This research earned these three scientists the 1984 Nobel Prize in chemistry. 

Deisenhofer, J., and Michel, H., 1989. The photosyndietic reaction center from die purple bacterium Rhodopseudomonas viridis. Science 245 1463-1473. Published version of die Nobel laureate address by the researchers who first elucidated the molecnlar structure of a photosyndietic reacdon center. 

See, e.g., J. Deisenhofer, H. Michel, The Photosynthetic Reaction Center from the Purple Bacterium Rhodopseudomonas-Viridis. Science 1989, 245, 1463-1473 M. E. Michel-Beyerle, M. Plato, J. Deisenhofer, H. Michel, M. Bixton, J. Jortner, Unidirectionality of Charge Separation in Reaction Centers of Photosynthetic Bacteria. Biochim. Biophys. Acta 1988, 932, 52-70. 

Of one purple bacterium, Rhodopseudomonas viridis, the structure of the reaction... 

J. Deisenhofer and H. Michel. 1989. The photosynthetic reaction centre from the purple bacterium Rhodopseudomonas viridis EMBOJ. 8 2149-2170. (PubMed)... 

It was when Hartmut Michel joined in. He was an associate of Dieter Oesterhelt here in the same Institute. He had already worked for some time on the preparation of membrane proteins. One day he came and he had some crystals of the protein from the purple bacterium Rhodopseudomonas viridis., and we put these crystals into our X-ray camera. These first crystals were not too good but they were promising. He then improved his procedure... 

A crucial protein at the photosynthetic reaction center of the purple bacterium Rhodopseudomonas viridis (see Section 20.6) has been separated from the organism, crystallized, and studied by x-ray diffraction. This substance crystallizes with a primitive unit cell in the tetragonal sys-... 

Deisenhofer, J. Michel, H. "The Photosynthetic Reaction Centre From the Purple Bacterium Rhodopseudomonas viridis," MBO J. 1989,8,2149-2170. 

The proteins most relevant to photosynthesis are membrane-bound and are therefore difficult to crystallize for structural analysis. Nevertheless, the RC from the purple bacterium Rhodopseudomonas (Rp.) viridis was the first membrane-bound protein from which well-ordered three-dimensional crystals were grown (Michel, 1982). The structure ofthis RC... 

Krueger BP, Scholes GD, Jimenez R, and Fleming GR (1998) Electronic excitation transfer from carotenoid to bacterio-chlorophyl in the purple bacterium Rhodopseudomonas acidophila. J Phys Chem, 102 2284-2292... 

Much recent e.s.r. evidence has indicated that A, in bacterial photosynthesis, is a 1 1 complex of ubiquinone and the non-haem iron molecule, (Fe-UQ). However, recent picosecond and nanosecond spectroscopic work58-80 on the reaction centres of the purple bacterium Rhodopseudomonas spheroides has shown that a transient state, PF, which is not simply the excited singlet of P870, forms even at redox potentials at which (Fe-UQ) is chemically reduced, and so cannot act as an electron acceptor. The changes of absorbance in the region 300— 900 nm accompanying the formation of state PF have been measured in some detail 58-80 but firm conclusions as to the nature of PF have not been reached it seems, however, very probable that state PF is the true primary product of electron transfer. 

J. P. Allen, G. Feher, T. O. Yeates, H. Komiya, and D. C. Rees, Structure of the reaction center from Rhodobacter sphaeroides R-26 The protein subunits, Proc. Natl. Acad. Sci. USA 4,6162-6166(1987). J. Deisenhofer and H. Michel, The photosynthetic reaction center from the purple bacterium Rhodopseudomonas viridis. Science 245, 1463-1473 (1989). 

Halloren E, McDermott G, Lindsay JG, Miller C, Freer AA, Isaacs NW and Cogdell RJ. Studies on the light-harvesting complexes from the thermotolerant purple bacterium Rhodopseudomonas cryptolactis. Photosynth. Res. 1995 44 149-155. 

It is now possible to obtain reaction centers (RC s) in crystalline form from the Bchl-b containing purple bacterium Rhodopseudomonas vividis. These crystalline RC s showed no substantial bleaching of the primary donor without addition of ubiquinone. (Michel, 1982). Improved preparations did show bleaching of the primary donor P960 at room temperature (Zinth et al., 1983). At low temperature however the crystalline structure may be damaged by ice-formation of intra-crystalline water. This may also damage the nativeness of the RC s.We therefore studied the low-temperature spectroscopic properties of the crystalline RC s. 

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