Abstract
Reaction centers of Rhodobacter sphaeroides undergo a approximately 20 A3/mole volume contraction in < 50 ns after excitation. The rapid volume change is tentatively assigned to electrostriction. From its magnitude, we infer that the effective dielectric coefficient is 10-15 if the compressibility of the reaction center is similar to that of globular proteins. The volume contraction is not sensitive to replacement of the natural ubiquinone at the QA site by other quinones or to the occupancy of the QB site. The quenching caused by pressure on the reaction centers most likely occurs on a faster time scale than that of electron transfer.
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Selected References
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- Arata H., Parson W. W. Enthalpy and volume changes accompanying electron transfer from P-870 to quinones in Rhodopseudomonas sphaeroides reaction centers. Biochim Biophys Acta. 1981 Jun 12;636(1):70–81. doi: 10.1016/0005-2728(81)90077-3. [DOI] [PubMed] [Google Scholar]
- Chidsey C. E., Takiff L., Goldstein R. A., Boxer S. G. Effect of magnetic fields on the triplet state lifetime in photosynthetic reaction centers: Evidence for thermal repopulation of the initial radical pair. Proc Natl Acad Sci U S A. 1985 Oct;82(20):6850–6854. doi: 10.1073/pnas.82.20.6850. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Devault D. Quantum mechanical tunnelling in biological systems. Q Rev Biophys. 1980 Nov;13(4):387–564. doi: 10.1017/s003358350000175x. [DOI] [PubMed] [Google Scholar]
- Gunner M. R., Honig B. Electrostatic control of midpoint potentials in the cytochrome subunit of the Rhodopseudomonas viridis reaction center. Proc Natl Acad Sci U S A. 1991 Oct 15;88(20):9151–9155. doi: 10.1073/pnas.88.20.9151. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mauzerall D. C., Drain C. M. Photogating of ionic currents across lipid bilayers. Electrostatics of ions and dipoles inside the membrane. Biophys J. 1992 Dec;63(6):1544–1555. doi: 10.1016/S0006-3495(92)81738-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Norris J. R., Bowman M. K., Budil D. E., Tang J., Wraight C. A., Closs G. L. Magnetic characterization of the primary state of bacterial photosynthesis. Proc Natl Acad Sci U S A. 1982 Sep;79(18):5532–5536. doi: 10.1073/pnas.79.18.5532. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Okamura M. Y., Isaacson R. A., Feher G. Primary acceptor in bacterial photosynthesis: obligatory role of ubiquinone in photoactive reaction centers of Rhodopseudomonas spheroides. Proc Natl Acad Sci U S A. 1975 Sep;72(9):3491–3495. doi: 10.1073/pnas.72.9.3491. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Reed D. W., Clayton R. K. Isolation of a reaction center fraction from Rhodopseudomonas spheroides. Biochem Biophys Res Commun. 1968 Mar 12;30(5):471–475. doi: 10.1016/0006-291x(68)90075-2. [DOI] [PubMed] [Google Scholar]
- Sharp K. A., Honig B. Electrostatic interactions in macromolecules: theory and applications. Annu Rev Biophys Biophys Chem. 1990;19:301–332. doi: 10.1146/annurev.bb.19.060190.001505. [DOI] [PubMed] [Google Scholar]
- Steffen M. A., Lao K., Boxer S. G. Dielectric asymmetry in the photosynthetic reaction center. Science. 1994 May 6;264(5160):810–816. doi: 10.1126/science.264.5160.810. [DOI] [PubMed] [Google Scholar]
- Treutlein H., Schulten K., Brünger A. T., Karplus M., Deisenhofer J., Michel H. Chromophore-protein interactions and the function of the photosynthetic reaction center: a molecular dynamics study. Proc Natl Acad Sci U S A. 1992 Jan 1;89(1):75–79. doi: 10.1073/pnas.89.1.75. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Warshel A., Aqvist J., Creighton S. Enzymes work by solvation substitution rather than by desolvation. Proc Natl Acad Sci U S A. 1989 Aug;86(15):5820–5824. doi: 10.1073/pnas.86.15.5820. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Woodbury N. W., Parson W. W., Gunner M. R., Prince R. C., Dutton P. L. Radical-pair energetics and decay mechanisms in reaction centers containing anthraquinones, naphthoquinones or benzoquinones in place of ubiquinone. Biochim Biophys Acta. 1986 Aug 13;851(1):6–22. doi: 10.1016/0005-2728(86)90243-4. [DOI] [PubMed] [Google Scholar]
