Molecular orbital investigation of dimer formations of bacteriochlorophyll a. Model configurations for the primary donor of photosynthesis

Plato, M.; Tränkle, E.; Lubitz, Wolfgang; Lendzian, Friedhelm; Möbius, K.

doi:10.1016/0301-0104(86)85003-0

Cited by 74 publications

(35 citation statements)

References 23 publications

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“…R. viridis. Recent ENDOR experiments together with molecular orbital calculations resulted in a model of the dimer consisting of two Bchls related by a C2 symmetry axis with one overlapping ring (37,38).…”

Section: Resultsmentioning

confidence: 99%

Structure of the reaction center from Rhodobacter sphaeroides R-26: the cofactors.

Allen

Fehér²,

Yeates³

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

908

608

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The three-dimensional structure of the cofactors of the reaction center of Rhodobacter sphaeroides R-26 has been determined by x-ray diffraction and refined at a resolution of 2.8 A with an R value of 26%. The main features of the structure are similar to the ones determined for Rhodopseudomonas viridis [Michel, H., Epp, 0. & Deisenhofer, J. (1986) EMBO J. 5, 2445EMBO J. 5, -2451. The cofactors are arranged along two branches, which are approximately related to each other by a 2-fold symmetry axis. The structure is well suited to produce light-induced charge separation across the membrane. Most of the structural features predicted from physical and biochemical measurements are confirmed by the x-ray structure.The reaction center (RC) is an integral membrane proteinpigment complex that mediates the primary processes of photosynthesis-i.e., the light-induced electron transfers from a donor to a series of acceptor species. The three-dimensional structure of the RC from the photosynthetic bacterium Rhodopseudomonas viridis has recently been determined by x-ray diffraction at a resolution of 2.9 A (1-3). In this paper, we report the structure analysis of the RC from another purple bacterium, the carotenoidless mutant R-26 of Rhodobacter sphaeroides (previously called Rhodopseudomonas sphaeroides). The motivation for undertaking the structure determination of the RC of a second bacterial species was 2-fold. (i) The RC from Rb. sphaeroides has been investigated for the past two decades and, consequently, is the best characterized RC (for reviews see refs. 4 and 5); in addition, the methodologies for manipulating its structure (e.g., exchanging cofactors, dissociating and reassociating the subunits) have been worked out in detail (4-10). (ii) The availability of structures from two organisms may help in elucidating structure-function relationships by correlating differences in structure with differences in function.The RC from Rb. sphaeroides is composed of three protein subunits-L, M, and H-and the following cofactors: four bacteriochlorophylls (Bchls), two bacteriopheophytins (Bphes), two ubiquinones, and one nonheme iron. The RC from R. viridis has an additional subunit, a cytochrome with four c-type hemes; its Bchls and Bphes are of the "b" type instead of the "a" type found in Rb. sphaeroides, and its primary quinone is a menaquinone. Notwithstanding these differences, the two structures were found to be very similar. This made it possible to use the method of molecular replacement (11) to solve the phase problem in the x-ray analysis (12)(13)(14). The crystals of Rb. sphaeroides diffract at least to a resolution of 2.6 A and retain the ability to perform the primary photochemistry (15). We have solved the structure of the protein and the cofactors to a resolution of 2.8 A with an R factor of 26%. In this paper, we report the structure of the cofactors. The structure of the protein, the relation of the RC protein to the membrane, and the interaction of the cofactors with the protein will be reported in ...

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Section: Resultsmentioning

confidence: 99%

Structure of the reaction center from Rhodobacter sphaeroides R-26: the cofactors.

Allen

Fehér²,

Yeates³

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

908

608

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“…Therefore, UHF calculations were avoided and instead we used a restricted HF method (RHF), based on the INDO semiempirical method, which uses a perturbation treatment to determine spin polarization (SP), developed by Plato and co-workers. 26,27 This method was developed for -radicals and has been shown previously to give good results.…”

Section: Choice Of Mo Methodsmentioning

confidence: 99%

EPR and ENDOR of radicals of chlorin- and bacteriochlorin-quinone model compounds for electron transfer in photosynthesis

et al. 2000

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“…in studies of photosynthetic reaction centres, the RHF INDO/SP method developed by Plato and Tränkle has been appropriate. [2] On the other hand, unrestricted Hartree-Fock (UHF) ab initio calculations are almost inapplicable because of severe spin contamination problems. In recent years, DFT calculations have become popular for the calculation of NMR and electron paramagnetic resonance (EPR) parameters.…”

Section: Introductionmentioning

confidence: 99%

DFT calculations of hyperfine coupling constants of organic π radicals and comparison with empirical equations and experiment

Kirste

2016

Magnetic Reson in Chemistry

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Density functional theory calculations (UB3LYP/EPR-III) for a series of radicals and radical ions were performed to check the internal consistency of the method and its implications to the theoretical concepts of electron paramagnetic resonance such as π-σ spin polarization, hyperconjugation and phenyl hyperconjugation. In the second part, experimental data for seven radicals (43 hyperfine coupling constants) are compared with calculations, yielding a correlation of r = 0.97. Copyright © 2016 John Wiley & Sons, Ltd.

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Molecular orbital investigation of dimer formations of bacteriochlorophyll a. Model configurations for the primary donor of photosynthesis

Cited by 74 publications

References 23 publications

Structure of the reaction center from Rhodobacter sphaeroides R-26: the cofactors.

Structure of the reaction center from Rhodobacter sphaeroides R-26: the cofactors.

EPR and ENDOR of radicals of chlorin- and bacteriochlorin-quinone model compounds for electron transfer in photosynthesis

DFT calculations of hyperfine coupling constants of organic π radicals and comparison with empirical equations and experiment

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