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Okamura MY, Feher G. Isotope effect on electron transfer in reaction centers from Rhodopseudomonas sphaeroides. Proc Natl Acad Sci U S A 2010; 83:8152-6. [PMID: 16593776 PMCID: PMC386885 DOI: 10.1073/pnas.83.21.8152] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Previous ENDOR studies on reaction centers from Rhodopseudomonas sphaeroides have shown the presence of two hydrogen-bonded protons associated with the primary, ubiquinone, acceptor Q(A). These protons exchange with deuterons from solvent (2)H(2)O. The effect of this deuterium substitution on the charge-recombination kinetics (BChl)(2) (+)Q(A) (-) --> (BChl)(2)Q(A) has been studied with a sensitive kinetic difference technique. The electron-transfer rate was found to increase with deuterium exchange up to a maximum Deltak/k of 5.7 +/- 0.3%. The change in rate was found to have an exchange time of 2 hr, which matched the disappearance of the ENDOR lines due to the exchangeable protons. These results indicate that these protons play a role in the vibronic coupling associated with electron transfer. A simple model for the isotope effect on electron transfer predicts a maximum rate increase of 20%, which is consistent with the experimental results.
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Affiliation(s)
- M Y Okamura
- Department of Physics, University of California, San Diego, La Jolla, CA 92093
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2
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Goldstein RF, Bearden A. Tunneling in Chromatium chromatophores: Detection of a Hopfield charge-transfer band. Proc Natl Acad Sci U S A 2010; 81:135-9. [PMID: 16593405 PMCID: PMC344625 DOI: 10.1073/pnas.81.1.135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have observed a weak charge-transfer band in the cytochrome c-P(870) electron-transfer reaction in Chromatium vinosum chromatophores at 10 K and at 85 K. First, the intermediate acceptor, I, was trapped in the reduced state by lowering the redox potential at room temperature, then illuminating with white light at low temperature for 20 min. Next, illumination by broadband infrared (1-3 mum, 6.5 kW/m(2)) for 4 hr at 10 K decreased the I(-) electron spin resonance signal by 30%. One-hour infrared illumination at 85 K decreased the cytochrome c Soret band shift by 10%. The effect of infrared was to promote the system from the ground vibrational state with the electron on P(870) to an excited vibrational state with the electron on cytochrome c. The absorption band peak is near 2 mum, and the integrated cross section is approximately 6 x 10(-3) eV.M(-1).cm(-1). These values are consistent with small (0.02 nm) nuclear motion and with electron-transfer rates measured in the dark.
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Affiliation(s)
- R F Goldstein
- Department of Biophysics and Medical Physics and Division of Biology and Medicine, Lawrence Berkeley Laboratory, University of California, Berkeley, CA 94720
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3
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Role of quantum chemical calculations in molecular biophysics with a historical perspective. Theor Chem Acc 2009. [DOI: 10.1007/s00214-009-0622-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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4
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Kirmaier C, Holten D. Low-Temperature Studies of Electron Transfer to the M Side of YFH Reaction Centers from Rhodobacter capsulatus. J Phys Chem B 2009; 113:1132-42. [DOI: 10.1021/jp807639e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, Missouri 63130-4889
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, Missouri 63130-4889
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5
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Mechanism of Charge Separation in Purple Bacterial Reaction Centers. THE PURPLE PHOTOTROPHIC BACTERIA 2009. [DOI: 10.1007/978-1-4020-8815-5_19] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Goychuk I, Petrov E, May V. Control of the dynamics of a dissipative two-level system by a strong periodic field. Chem Phys Lett 1996. [DOI: 10.1016/0009-2614(96)00323-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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8
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Laporte L, Kirmaier C, Schenck CC, Holten D. Free-energy dependence of the rate of electron transfer to the primary quinone in beta-type reaction centers. Chem Phys 1995. [DOI: 10.1016/0301-0104(95)00036-n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Venturoli G, Trotta M, Feick R, Melandri BA, Zannoni D. Temperature dependence of charge recombination from the P+QA- and P+QB- states in photosynthetic reaction centers isolated from the thermophilic bacterium Chloroflexus aurantiacus. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 202:625-34. [PMID: 1761060 DOI: 10.1111/j.1432-1033.1991.tb16416.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The temperature dependence of charge recombination from the P+QA- and from the P+QB- states produced by a flash was studied in reaction centers isolated from the photosynthetic thermophilic bacterium Chloroflexus aurantiacus. P designates the primary electron donor; QA and QB the primary and secondary quinone electron acceptors respectively. In QB-depleted reaction centers the rate constant (kAP) for P+QA- recombination was temperature independent between 0-50 degrees C (17.6 +/- 0.7 s-1 at pH 8 and pH 10). The same value was obtained in intact membranes in the presence of o-phenanthroline. Upon lowering the temperature from 250 K to 160 K, kAP increased by a factor of two and remained constant down to 80 K. The overall temperature dependence of kAP was consistent with an activationless process. Ubiquinone (UQ-3) and different types of menaquinone were used for QB reconstitution. In UQ-3 reconstituted reaction centers charge recombination was monoexponential (rate constant k = 0.18 +/- 0.03 s-1) and temperature independent between 5-40 degrees C. In contrast, in menaquinone-3- and menaquinone-4-reconstituted reaction centers P+ rereduction following a flash was markedly biphasic and temperature dependent. In menaquinone-6-reconstituted reaction centers a minor contribution from a third kinetic phase corresponding to P+QA- charge recombination was detected. Analysis of these kinetics and of the effects of the inhibitor o-phenanthroline at high temperature suggest that in detergent suspensions of menaquinone-reconstituted reaction centers a redox reaction removing electrons from the quinone acceptor complex competes with charge recombination. Instability of the semiquinone anions is more pronounced when QB is a short-chain menaquinone. From the temperature dependence of P+ decay the activation parameters for the P+QB- recombination and for the competing side oxidation of the reduced menaquinone acceptor have been derived. For both reactions the activation enthalpies and entropies change markedly with menaquinone chain length but counterbalance each other, resulting in activation free energies at ambient temperature independent of the menaquinone tail. When reaction centers are incorporated into phospholipid vesicles containing menaquinone-8 a temperature-dependent, monophasic, o-phenanthroline-sensitive recombination from the P+QB- state is observed, which is consistent with the formation of stable semiquinone anions. This result seems to indicate a proper QB functioning in the two-subunit reaction center isolated from Chlorflexus aurantiacus when the complex is inserted into a lipid bilayer.
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Affiliation(s)
- G Venturoli
- Dipartimento di Biologia, Università di Bologna, Italy
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10
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Riveros OJ. Dynamics of electron transfer in the oxidation of water by chlorophyll a dimer. Biophys Chem 1991; 40:109-15. [PMID: 17014776 DOI: 10.1016/0301-4622(91)85035-o] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/1990] [Revised: 11/08/1990] [Accepted: 11/08/1990] [Indexed: 11/17/2022]
Abstract
The observed temperature dependence of the rate constant for reduction of (Chl a.2H2O)2+. by water is fitted to a theoretical expression for the rate of an intramolecular electronic radiationless transition. The theory assumes a single effective mediating mode and the best-fit value for the frequency of this mode is omega(m) = 680 cm(-1), which corresponds to high-frequency, intermolecular librations in water. From an explicit calculation of the nonadiabatic-coupling matrix element, an average electron-transfer distance of 11 A is obtained, consistent with molecular dimensions available for this system.
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Affiliation(s)
- O J Riveros
- Facultad de Física, Universidad Católica, Casilla 6177, Santiago, Chile
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Kirmaier C, Gaul D, DeBey R, Holten D, Schenck CC. Charge separation in a reaction center incorporating bacteriochlorophyll for photoactive bacteriopheophytin. Science 1991; 251:922-7. [PMID: 2000491 DOI: 10.1126/science.2000491] [Citation(s) in RCA: 244] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Site-directed mutagenic replacement of M subunit Leu214 by His in the photosynthetic reaction center (RC) from Rhodobacter sphaeroides results in incorporation of a bacteriochlorophyll molecule (BChl) in place of the native bacteriopheophytin (BPh) electron acceptor. Evidence supporting this conclusion includes the ground-state absorption spectrum of the (M)L214H mutant, pigment and metal analyses, and time-resolved optical experiments. The genetically modified RC supports transmembrane charge separation from the photoexcited BChl dimer to the primary quinone through the new BChl molecule, but with a reduced quantum yield of 60 percent (compared to 100 percent in wild-type RCs). These results have important implications for the mechanism of charge separation in the RC, and rationalize the choice of (bacterio)pheophytins as electron acceptors in a variety of photosynthetic systems.
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Affiliation(s)
- C Kirmaier
- Department of Chemistry, Washington University St. Louis, MO 63130
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Kuznetsov A, Ulstrup J. Protein dynamics and electronic fluctuation effects in electron transfer reactions of membrane-bound proteins and metalloprotein complexes. J Electroanal Chem (Lausanne) 1989. [DOI: 10.1016/0022-0728(89)87230-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Kuznetsov A, Ulstrup J. Protein dynamics and electronic fluctuation effects in electron transfer reactions of membrane-bound proteins and metalloprotein complexes. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0302-4598(89)85008-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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14
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Bixon M, Jortner J. Cytochrome oxidation in bacterial photosynthesis. PHOTOSYNTHESIS RESEARCH 1989; 22:29-37. [PMID: 24424676 DOI: 10.1007/bf00114764] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/1989] [Accepted: 04/19/1989] [Indexed: 06/03/2023]
Abstract
In this paper we propose that the reduction of the bacteriochlorophyl dimer cation (P(+)) by cytochrome c in the photosynthetic bacteria Rps. viridis and Chromatium vinosum proceeds via two parallel electron transfer (ET) processes from two distinct cytochrome c molecules. The dominating ET process at high temperatures involves the activated oxidation of the high-potential cytochrome c at closest proximity to P, while the dominating low-temperature process involves activationless ET from a low-potential cytochrome c, which is further away from P. The available data for the effects of blocking the low-potential cytochrome c on ET dynamics are consistent with this model, which results in reasonable nuclear reorganization and electronic coupling parameters for the parallel cytochrome oxidation processes. The lack of universality in the cytochrome oxidation in reaction centres of various bacteria is emphasized.
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Affiliation(s)
- M Bixon
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, 69978, Tel-Aviv, Israel
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Kirmaier C, Holten D. Primary photochemistry of reaction centers from the photosynthetic purple bacteria. PHOTOSYNTHESIS RESEARCH 1987; 13:225-260. [PMID: 24435821 DOI: 10.1007/bf00029401] [Citation(s) in RCA: 264] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/1987] [Accepted: 04/20/1987] [Indexed: 06/03/2023]
Abstract
Photosynthetic organisms transform the energy of sunlight into chemical potential in a specialized membrane-bound pigment-protein complex called the reaction center. Following light activation, the reaction center produces a charge-separated state consisting of an oxidized electron donor molecule and a reduced electron acceptor molecule. This primary photochemical process, which occurs via a series of rapid electron transfer steps, is complete within a nanosecond of photon absorption. Recent structural data on reaction centers of photosynthetic bacteria, combined with results from a large variety of photochemical measurements have expanded our understanding of how efficient charge separation occurs in the reaction center, and have changed many of the outstanding questions.
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Affiliation(s)
- C Kirmaier
- Department of Chemistry, Washington University, 63130, St. Louis, MO, USA
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Feher G, Okamura M, Kleinfeld D. Electron Transfer Reactions in Bacterial Photosynthesis: Charge Recombination Kinetics as a Structure Probe. PROCEEDINGS IN LIFE SCIENCES 1987. [DOI: 10.1007/978-1-4612-4796-8_25] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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18
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Kuznetsov A, Ulstrup J. Continuous medium mode representations for biological charge transfer processes. Chem Phys 1986. [DOI: 10.1016/0301-0104(86)85015-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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19
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Volkov AG. The electrochemical mechanism of photosystem II functioning in chloroplasts. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/0022-0728(86)90235-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Does Cytochrome Oxidation in Bacterial Photosynthesis Manifest Tunneling Effects? ACTA ACUST UNITED AC 1986. [DOI: 10.1007/978-94-009-4752-8_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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22
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Guarr T, McLendon G. Quantum mechanical effects in inorganic and bioinorganic electron transfer. Coord Chem Rev 1985. [DOI: 10.1016/0010-8545(85)80029-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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23
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Cartling B. A stochastic model of protein conformational dynamics and electronic–conformational coupling in biological energy transduction. J Chem Phys 1985. [DOI: 10.1063/1.449737] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Temperature and detection-wavelength dependence of the picosecond electron-transfer kinetics measured in Rhodopseudomonas sphaeroides reaction centers. Resolution of new spectral and kinetic components in the primary charge-separation process. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1985. [DOI: 10.1016/0005-2728(85)90204-x] [Citation(s) in RCA: 187] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kinetics and Mechanisms of Initial Electron-Transfer Reactions in Rhodopseudomonas sphaeroides Reaction Centers. ACTA ACUST UNITED AC 1985. [DOI: 10.1007/978-3-642-82688-7_38] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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28
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Mar T, Bouchard J. Use of 8-analino-1-naphthalene sulfonate as a monitor for possible phase transition involving water at low temperatures in photoreaction center from Rhodospirillum rubrum. PHOTOSYNTHESIS RESEARCH 1984; 5:129-137. [PMID: 24458601 DOI: 10.1007/bf00028526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/1983] [Revised: 12/15/1983] [Indexed: 06/03/2023]
Abstract
The increase in the rate of the primary back reaction on cooling the photoreaction center from Rhodospirillum rubrum was interpreted in terms of a model in which the peculiar temperature dependence of the rate results from a phase transition involving water. The primary back reaction is defined as the return of the electron from the reduced primary ubiquinone to the oxidized bacteriochlorophyll molecules following illumination. The dye 8-anilino-1-naphthalene sulfonate was used to detect the state of the water solvent as it transforms on cooling from a liquid to a solid glass. We inferred from studies with air-dried films of photoreaction center that the water which may be responsible for the unusual temperature dependence of the rate of the primary back reaction is not on the surface but is bound within the photoreaction center protein.
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Affiliation(s)
- T Mar
- Department de Biochimie, Université de Montréal, Montréal, Québec, Canada
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Different temperature dependencies of the charge recombination reaction in photoreaction centers isolated from different bacterial species. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1983. [DOI: 10.1016/0005-2728(83)90090-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Schenck CC, Parson WW, Holten D, Windsor MW, Sarai A. Temperature dependence of electron transfer between bacteriopheophytin and ubiquinone in protonated and deuterated reaction centers of Rhodopseudomonas sphaeroides. Biophys J 1981; 36:479-89. [PMID: 6275918 PMCID: PMC1327641 DOI: 10.1016/s0006-3495(81)84747-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The rate of the electron-transfer reaction between bacteriopheophytin and the first quinone in isolated reaction centers of Rhodopseudomonas sphaeroides has an unusual temperature dependence. The rate increases about threefold with decreasing temperature between 300 and 25 K, and decreases abruptly at temperatures below 25 K. Partial deuteration of the reaction centers alters the temperature dependence of the rate constant. Qualitative features of the temperature dependence can be understood in the context of a theory of nonadiabatic electron transfer (Sarai, 1980. Biochim. Biophys. Acta 589:71-83). We conclude that very low-energy (10-50 cm-1) processes, perhaps skeletal vibrations of the protein, are important to electron transfer. Higher-energy vibrations, possibly involving the pyrrolic N--H bonds of bacteriopheophytin, also are important in this process.
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Kakitani T, Kakitani H. A possible new mechanism of temperature dependence of electron transfer in photosynthetic systems. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 635:498-514. [PMID: 7236675 DOI: 10.1016/0005-2728(81)90109-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A new theory for the electron transfer by the non-adiabatic process is formulated taking into account the origin shift and the frequency change of the vibration. The resultant formulas are quite similar to those of Jortner (Jortner, J. (1976) J. Chem. Phys. 64, 4860-4867) except that the free energy gap delta G is used instead of the energy gap delta E. By applying this theory to the photosynthetic electron transfer, the role of the remarkable temperature dependence of the electron transfer from cytochrome to P+ in Chromatium vinosum and the experimental data were reproduced very well using a small value of the coupling strength in contrast with the previous theory. This implies that proteins play a role to exclude many of the solvent molecules from the region of the electron transfer reaction between the donor and acceptor molecules. The negative activation process in the back electron transfer from QA- to P+, the very slow back electron transfer from I- to P+ and the solvent isotope effect on the cytochrome oxidation are also successfully explained by this new theory. It is shown that even a qualitative conclusion as to the molecular parameters obtained from the temperature dependence of the electron transfer is different between the present theory and that of Jortner.
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Jortner J. Dynamics of electron transfer in bacterial photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 594:193-230. [PMID: 7018575 DOI: 10.1016/0304-4173(80)90001-4] [Citation(s) in RCA: 152] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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36
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Sarai A, Yomosa S. TEMPERATURE DEPENDENCE OF PHOTOSYNTHETIC EXCITATION TRANSFER—ACTIVATIONLESS TRANSFER. Photochem Photobiol 1980. [DOI: 10.1111/j.1751-1097.1980.tb03749.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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