scholarly journals Electronic Structure of the Primary Electron Donor P700+• in Photosystem I Studied by Multifrequency HYSCORE Spectroscopy at X- and Q-Band

2020 ◽  
Author(s):  
Melanie M. Chestnut ◽  
Sergey Milikisiyants ◽  
Ruchira Chatterjee ◽  
Jan Kern ◽  
Alex I. Smirnov
Keyword(s):  
Electronic Structure ◽  
Electron Donor ◽  
Photosystem I ◽  
Primary Electron ◽  
Primary Electron Donor ◽  
Primary Electron Donor P700

scholarly journals Electrogenic reduction of the primary electron donor P700 by plastocyanin in photosystem I complexes

FEBS Letters ◽  
2001 ◽  
Vol 500 (3) ◽  
pp. 172-176 ◽  
Author(s):  
Mahir D. Mamedov ◽  
Aygun A. Mamedova ◽  
Sergey K. Chamorovsky ◽  
Alexey Yu. Semenov
Keyword(s):  
Electron Donor ◽  
Photosystem I ◽  
Primary Electron ◽  
Primary Electron Donor ◽  
Primary Electron Donor P700

Heat-stress stimulation of electron flow in a photosystem I submembrane fraction

1990 ◽  
Vol 68 (7-8) ◽  
pp. 999-1004 ◽  
Author(s):  
Natalie Boucher ◽  
Johanne Harnois ◽  
Robert Carpentier
Keyword(s):  
Heat Stress ◽  
Cytochrome B ◽  
Electron Donor ◽  
Photosystem I ◽  
Conformational Changes ◽  
Electron Flow ◽  
Primary Electron ◽  
Primary Electron Donor ◽  
Terminal Electron Acceptor ◽  
Stimulation Of

Oxygen uptake using methyl viologen as the terminal electron acceptor was recorded in digitonin-derived photosystem I submembrane fractions incubated at either 25 or 50 °C. A two- to four-fold heat-stress stimulation of electron flow was detected at 50 °C when reduced 2,6-dichlorophenol-indophenol was used as the primary electron donor. However, no stimulation was seen with N,N,N′,N′ -tetramethylphenylenediamine as the donor. The stimulation was enhanced by specific cations (Mg2+, Na+, K+), but not by Mn2 or Ca2+. The enhancement obtained with Mg2+ could be eliminated by incubating for a prolonged period. It is proposed that the observed heat-stress stimulation is due to a conformational change at the level of the cytochrome b6–f complex. This change increased the affinity of the protein complex for 2,6-dichlorophenol-indophenol at its oxidation sites. The involvement of a conformational modification is demonstrated by the absence of heat-stress stimulation in submembrane fractions immobilized in an albumin–glutaraldehyde cross-linked matrix.Key words: electron transport, photosystem I, heat stress, cytochrome b6–f complex, conformational changes, electron donor.

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