Primary electron transfer reactions in modified reaction centers from Rhodopseudomonas sphaeroides
Absorption spectra were measured by means of an optical multichannel analyzer in Rhodopseudomonas sphaeroides R-26 reaction centers (RCs) modified by treatment with NaBH/sub 4/ at various times after the onset of a short excitation flash at 880 nm. Most of these RCs (75-95%) have only one monomeric bacteriochlorophyll-800 (B/sub 1/) molecule and are as active as the original RCs. The duration of the excitation and measuring pulses was approx. = 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 P/sup E/ (early state), which is converted to the state P/sup F/ (P/sup +/ bacteriopheophytin/sup -/) in 4 +/- 1 ps (1/e time), was observed. Also the kinetics and the spectrum of the stimulated emission were determined. The difference spectrum of the state P/sup E/ approximately equals the sum of the spectra of the states P* and /sup 1/(P/sup +/B/sub 1//sup -/). This indicated that B/sub 1//sup -/ is an intermediate in the electron transfer from P* to bacteriopheophytin, H/sub 1/, transferring this electron with a rate constant of (4 x 0.35 ps)/sup -1/ = 7 x 10/sup 11/ s/sup -1/.
- Research Organization:
- Huygens Lab. of the State Univ., Leiden, Netherlands
- OSTI ID:
- 5861812
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 83:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PHOTOSYNTHESIS
ELECTRON TRANSFER
PHOTOSYNTHETIC REACTION CENTERS
ABSORPTION SPECTRA
BIOCHEMICAL REACTION KINETICS
CHLOROPHYLL
LASER SPECTROSCOPY
RHODOPSEUDOMONAS
BACTERIA
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
KINETICS
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
REACTION KINETICS
SPECTRA
SPECTROSCOPY
SYNTHESIS
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)