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. 1986 Mar;83(6):1690–1694. doi: 10.1073/pnas.83.6.1690

Primary electron transfer reactions in modified reaction centers from Rhodopseudomonas sphaeroides

V A Shuvalov 1,†, L N M Duysens 1,‡
PMCID: PMC323149  PMID: 16593664

Abstract

Absorption spectra were measured by means of an optical multichannel analyzer in Rhodopseudomonas sphaeroides R-26 reaction centers (RCs) modified by treatment with NaBH4 at various times (≥1 ps) after the onset of a short excitation flash at 880 nm. Most of these RCs (75-95%) have only one “monomeric” bacteriochlorophyll-800 (B1) molecule and are as active as the original RCs. The duration of the excitation and measuring pulses was ≈33 ps. If the center of the excitation pulse preceded the center of the measuring pulse by 36-40 ps, the formation of a state PE (early state), which is converted to the state PF (P+ bacteriopheophytin-) in 4 ± 1 ps (1/e time), was observed. Also the kinetics and the spectrum of the stimulated emission (reflecting the kinetics and the emission spectrum of the excited state P*) were determined. The difference spectrum of the state PE approximately equals the sum of the spectra of the states P* (≈65%) and 1[P+B1-] (≈35%). This indicates that B1- is an intermediate in the electron transfer from P* to bacteriopheophytin, H1, transferring this electron with a rate constant of (4 × 0.35 ps)-1 = 7 × 1011 s-1.

Keywords: bacteriochlorophyll, bacteriopheophytin, photosynthesis, charge separation

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Deisenhofer J., Epp O., Miki K., Huber R., Michel H. X-ray structure analysis of a membrane protein complex. Electron density map at 3 A resolution and a model of the chromophores of the photosynthetic reaction center from Rhodopseudomonas viridis. J Mol Biol. 1984 Dec 5;180(2):385–398. doi: 10.1016/s0022-2836(84)80011-x. [DOI] [PubMed] [Google Scholar]
  2. Fajer J., Brune D. C., Davis M. S., Forman A., Spaulding L. D. Primary charge separation in bacterial photosynthesis: oxidized chlorophylls and reduced pheophytin. Proc Natl Acad Sci U S A. 1975 Dec;72(12):4956–4960. doi: 10.1073/pnas.72.12.4956. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Martin J. L., Breton J., Hoff A. J., Migus A., Antonetti A. Femtosecond spectroscopy of electron transfer in the reaction center of the photosynthetic bacterium Rhodopseudomonas sphaeroides R-26: Direct electron transfer from the dimeric bacteriochlorophyll primary donor to the bacteriopheophytin acceptor with a time constant of 2.8 +/- 0.2 psec. Proc Natl Acad Sci U S A. 1986 Feb;83(4):957–961. doi: 10.1073/pnas.83.4.957. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Maslov V. G., Klevanik A. V., Ismailov M. A., Shuvalov V. A. O prirode dlinnovolnovoi polosy pogloshcheniia reaktsionnykh tsentrov Rhodopseudomonas viridis v sviazi s protsessom pervichnogo razdeleniia zariadov. Dokl Akad Nauk SSSR. 1983;269(5):1217–1221. [PubMed] [Google Scholar]
  5. Parson W. W. Photosynthetic bacterial reaction centers: interactions among the bacteriochlorophylls and bacteriopheophytins. Annu Rev Biophys Bioeng. 1982;11:57–80. doi: 10.1146/annurev.bb.11.060182.000421. [DOI] [PubMed] [Google Scholar]
  6. Shuvalov V. A., Asadov A. A. Arrangement and interaction of pigment molecules in reaction centers of Rhodopseudomonas viridis. Photodichroism and circular dichroism of reaction centers at 100 k. Biochim Biophys Acta. 1979 Feb 8;545(2):296–308. doi: 10.1016/0005-2728(79)90207-x. [DOI] [PubMed] [Google Scholar]
  7. Shuvalov V. A., Klevanik A. V., Sharkov AV J. u., Matveetz A., Krukov P. G. Picosecond detection of BChl-800 as an intermediate electron carrier between selectively-excited p870 and bacteriopheophytin in Rhodospirillum rubrum relaction centers. FEBS Lett. 1978 Jul 1;91(1):135–139. doi: 10.1016/0014-5793(78)80034-9. [DOI] [PubMed] [Google Scholar]
  8. Shuvalov V. A., Parson W. W. Energies and kinetics of radical pairs involving bacteriochlorophyll and bacteriopheophytin in bacterial reaction centers. Proc Natl Acad Sci U S A. 1981 Feb;78(2):957–961. doi: 10.1073/pnas.78.2.957. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Woodbury N. W., Becker M., Middendorf D., Parson W. W. Picosecond kinetics of the initial photochemical electron-transfer reaction in bacterial photosynthetic reaction centers. Biochemistry. 1985 Dec 17;24(26):7516–7521. doi: 10.1021/bi00347a002. [DOI] [PubMed] [Google Scholar]

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