Analysis of the P680+˙ reduction pattern and its temperature dependence in oxygen-evolving PS II core complexes from thermophilic cyanobacteria and higher plants

2004 ◽  
Vol 6 (20) ◽  
pp. 4838-4843 ◽  
Author(s):  
P. Kühn ◽  
H.-J. Eckert ◽  
H. J. Eichler ◽  
G. Renger
Keyword(s):  
Temperature Dependence ◽  
Higher Plants ◽  
Ps Ii ◽  
Thermophilic Cyanobacteria ◽  
Oxygen Evolving ◽  
Ps Ii Core Complexes ◽  
Ps Ii Core

Electron Transport from QA to Thymoquinone in a Synechococcus Oxygen-Evolving Photosystem II Preparation: Role of QB and Binding Affinity of Thymoquinone to the QB Site

1993 ◽  
Vol 48 (3-4) ◽  
pp. 174-178 ◽  
Author(s):  
Kazuhiko Satoh ◽  
Yasuhiro Kashino ◽  
Hiroyuki Koike
Keyword(s):  
Binding Affinity ◽  
Turnover Rate ◽  
Side Chain ◽  
Head Group ◽  
Binding Affinities ◽  
Ps Ii ◽  
Thermophilic Cyanobacteria ◽  
High Concentrations ◽  
Oxygen Evolving

Abstract We have recently shown that binding affinities of benzoquinones can be estimated by two methods in photosystem (PS) II particles (K. Satoh et al., Biochim. Biophys. Acta 1102, 45-52 (1992)). Using these methods we calculated the binding affinity of thymoquinone (2-methyl-5-isopropyl-p-benzoquinone) to the QB site and studied how the quinone accepts electrons in oxygen-evolving PS II particles isolated from the thermophilic cyanobacteria, Synechococcus elongatus and S. vulcanus. The results are as follows: (1) The binding constant of thymoqui­ none to the QB site determined by several methods was around 0.33 mᴍ . (2) At low thymoquinone concentrations the quinone was supposed to accept electrons via QB-plastoquinone, whereas at high concentrations the quinone seemed to bind to the QB site and accept an electron directly from Q-A. Lower rates of photoreduction of the quinone at high concentrations were attributed to a slower turnover rate of the quinone at the QB site than that of endogenous plastoquinone. (3) A model for the function of plastoquinone at the QB site, which can explain all the results, was presented. According to this model, the plastoquinone molecule at the QB site is not replaced by another plastoquinone molecule. Instead, it transfers electrons to pool plastoquinone molecules by turning over its head group but remaining its long side chain bound to the PS II complexes.

Reconstitution of the Endogenous Plastoquinone Pool in Photosystem II (PS II) Membrane Fragments, Inside-Out-Vesicles, and PS II Core Complexes from Spinach

Biochemistry ◽  
1995 ◽  
Vol 34 (48) ◽  
pp. 15721-15731 ◽  
Author(s):  
J. Kurreck ◽  
A. G. Seeliger ◽  
F. Reifarth ◽  
M. Karge ◽  
G. Renger
Keyword(s):  
Photosystem Ii ◽  
Ps Ii ◽  
Plastoquinone Pool ◽  
Inside Out ◽  
Ps Ii Core Complexes ◽  
Ps Ii Core

Effects of hydrogen/deuterium exchange on photosynthetic water cleavage in PS II core complexes from spinach

FEBS Letters ◽  
1996 ◽  
Vol 378 (2) ◽  
pp. 140-144 ◽  
Author(s):  
M. Karge ◽  
K.-D. Irrgang ◽  
S. Sellin ◽  
R. Feinäugle ◽  
B. Liu ◽  
...  
Keyword(s):  
Deuterium Exchange ◽  
Hydrogen Deuterium Exchange ◽  
Ps Ii ◽  
Hydrogen Deuterium ◽  
Water Cleavage ◽  
Ps Ii Core Complexes ◽  
Ps Ii Core
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