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Some experiments on the primary electron acceptor in reaction centres from Rhodopseudomanas sphaeroides

Journal Article:

Abstract

The bacterial reaction center absorbance change at 450 nm (A-450), assigned to an anionic semiquinone, has been suggested as a candidate for the reduced form of the primary electron acceptor in bacterial photosynthesis. In reaction centers of Rhodopseudomonas sphaeroides we have found kinetic discrepancies between the decay of A-450 and the recovery of photochemical competence. In addition, no proton uptake is measurable on the first turnover, although subsequent ones elicit one proton bound per electron. These results are taken to indicate that the acceptor reaction after a long dark period may be different for the first turnover than for subsequent ones. It is suggested that A-450 is still a likely candidate for the acceptor function but that in reaction centers, additional quinone may act as an adventitious primary acceptor when the ''true'' primary acceptor is reduced. Alternatively, the primary acceptor may act in a ''ping-pong'' fashion with respect to subsequent photoelectrons.
Publication Date:
Jan 01, 1975
Product Type:
Journal Article
Reference Number:
ERA-02-036274; EDB-77-083678
Resource Relation:
Journal Name: Biochim. Biophys. Acta; (Netherlands); Journal Volume: 396
Subject:
59 BASIC BIOLOGICAL SCIENCES; BACTERIA; PHOTOCHEMISTRY; BIOCHEMICAL REACTION KINETICS; PHOTOSYNTHESIS; ELECTRON TRANSFER; ELECTRONS; PROTONS; QUINONES; AROMATICS; BARYONS; CHEMICAL REACTIONS; CHEMISTRY; ELEMENTARY PARTICLES; FERMIONS; HADRONS; KINETICS; LEPTONS; MICROORGANISMS; NUCLEONS; ORGANIC COMPOUNDS; ORGANIC OXYGEN COMPOUNDS; PHOTOCHEMICAL REACTIONS; REACTION KINETICS; SYNTHESIS; 550700* - Microbiology; 550200 - Biochemistry
OSTI ID:
7223073
Research Organizations:
Cornell Univ., Ithaca, NY
Country of Origin:
Netherlands
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: BBACA
Submitting Site:
TIC
Size:
Pages: 242-249
Announcement Date:
Jun 01, 1977

Journal Article:

Citation Formats

Wraight, C A, Cogdell, R J, and Clayton, R K. Some experiments on the primary electron acceptor in reaction centres from Rhodopseudomanas sphaeroides. Netherlands: N. p., 1975. Web.
Wraight, C A, Cogdell, R J, & Clayton, R K. Some experiments on the primary electron acceptor in reaction centres from Rhodopseudomanas sphaeroides. Netherlands.
Wraight, C A, Cogdell, R J, and Clayton, R K. 1975. "Some experiments on the primary electron acceptor in reaction centres from Rhodopseudomanas sphaeroides." Netherlands.
@misc{etde_7223073,
title = {Some experiments on the primary electron acceptor in reaction centres from Rhodopseudomanas sphaeroides}
author = {Wraight, C A, Cogdell, R J, and Clayton, R K}
abstractNote = {The bacterial reaction center absorbance change at 450 nm (A-450), assigned to an anionic semiquinone, has been suggested as a candidate for the reduced form of the primary electron acceptor in bacterial photosynthesis. In reaction centers of Rhodopseudomonas sphaeroides we have found kinetic discrepancies between the decay of A-450 and the recovery of photochemical competence. In addition, no proton uptake is measurable on the first turnover, although subsequent ones elicit one proton bound per electron. These results are taken to indicate that the acceptor reaction after a long dark period may be different for the first turnover than for subsequent ones. It is suggested that A-450 is still a likely candidate for the acceptor function but that in reaction centers, additional quinone may act as an adventitious primary acceptor when the ''true'' primary acceptor is reduced. Alternatively, the primary acceptor may act in a ''ping-pong'' fashion with respect to subsequent photoelectrons.}
journal = {Biochim. Biophys. Acta; (Netherlands)}
volume = {396}
journal type = {AC}
place = {Netherlands}
year = {1975}
month = {Jan}
}