Skip to main content
NCBI home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1986 Mar;83(6):1699–1703. doi: 10.1073/pnas.83.6.1699

Excitation trapping and primary charge stabilization in Rhodopseudomonas viridis cells, measured electrically with picosecond resolution

J Deprez †, H W Trissl ‡, J Breton †
PMCID: PMC323151  PMID: 16593665

Abstract

The transmembrane primary charge separation in the photosynthetic bacterium Rhodopseudomonas viridis was monitored by electric measurements of the light-gradient type [Trissl, H. W. & Kunze, U. (1985) Biochim. Biophys. Acta 806, 136-144]. Excitation of whole cells with 30-ps laser pulses at either 532 nm or 1064 nm gave rise to a biphasic increase of the photovoltage. The fast phase, contributing about 50% of the total, rose with an exponential time constant ≤40 ps and was independent of the redox state of the quinone electron acceptor. It is assigned to the migration of the excitation energy in the antenna and its subsequent trapping by the reaction center, monitored by the ultrafast charge separation between the primary electron donor and the bacteriopheophytin intermediary acceptor. The slower phase (125 ± 50 ps) only occurred when the quinone was oxidized and disappeared when it was reduced (either chemically or photochemically). It is assigned to the forward electron transfer from the bacteriopheophytin to the quinone. The relative amplitudes of these two electrogenic steps demonstrate that the bacteriopheophytin intermediary acceptor is located halfway between the primary donor and the quinone.

Keywords: photosynthesis, electron transfer, light gradient, capacitative metal electrodes

Full text

PDF
1699

Selected References

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

  1. COHEN-BAZIRE G., SISTROM W. R., STANIER R. Y. Kinetic studies of pigment synthesis by non-sulfur purple bacteria. J Cell Physiol. 1957 Feb;49(1):25–68. doi: 10.1002/jcp.1030490104. [DOI] [PubMed] [Google Scholar]
  2. Campillo A. J., Hyer R. C., Monger T. G., Parson W. W., Shapiro S. L. Light collection and harvesting processes in bacterial photosynthesis investigated on a picosecond time scale. Proc Natl Acad Sci U S A. 1977 May;74(5):1997–2001. doi: 10.1073/pnas.74.5.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Carithers R. P., Parson W. W. Delayed fluorescence from Rhodopseudomonas viridis following single flashes. Biochim Biophys Acta. 1975 May 15;387(2):194–211. doi: 10.1016/0005-2728(75)90103-6. [DOI] [PubMed] [Google Scholar]
  4. 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]
  5. Fowler C. F., Kok B. Direct observation of a light-induced electric field in chloroplasts. Biochim Biophys Acta. 1974 Aug 23;357(2):308–318. doi: 10.1016/0005-2728(74)90069-3. [DOI] [PubMed] [Google Scholar]
  6. Godik V. I., Borisov A. Y. Short-lived delayed luminescence of photosynthetic organisms. I. Nanosecond afterglows in purple bacteria at low redox potentials. Biochim Biophys Acta. 1979 Nov 8;548(2):296–308. doi: 10.1016/0005-2728(79)90137-3. [DOI] [PubMed] [Google Scholar]
  7. Holten D., Windsor M. W., Parson W. W., Thornber J. P. Primary photochemical processes in isolated reaction centers of Rhodopseudomonas viridis. Biochim Biophys Acta. 1978 Jan 11;501(1):112–126. doi: 10.1016/0005-2728(78)90100-7. [DOI] [PubMed] [Google Scholar]
  8. 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]
  9. Prince R. C., Tiede D. M., Thornber J. P., Dutton P. L. Spectroscopic properties of the intermediary electron carrier in the reaction center of Rhodopseudomonas viridis. Evidence for its interaction with the primary acceptor. Biochim Biophys Acta. 1977 Nov 17;462(2):467–490. doi: 10.1016/0005-2728(77)90143-8. [DOI] [PubMed] [Google Scholar]
  10. Trissl H. W. Spatial correlation between primary redox components in reaction centers of Rhodopseudomonas sphaeroides measured by two electrical methods in the nanosecond range. Proc Natl Acad Sci U S A. 1983 Dec;80(23):7173–7177. doi: 10.1073/pnas.80.23.7173. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Witt H. T., Zickler A. Electrical evidence for the field indicating absorption change in bioenergetic membranes. FEBS Lett. 1973 Dec 1;37(2):307–310. doi: 10.1016/0014-5793(73)80484-3. [DOI] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES