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Issue 12, 2014
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Static magnetic field (SMF) sensing of the P723/P689 photosynthetic complex

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Abstract

Moderate intensity SMF have been shown to act as a controller of the protic potential in the coherent milieu of the thylakoid membranes. SMF of the order of 60–500 mT induces memory-like effect in photosystem I (PSI, P723) emission with a correlated oscillation of photosystem II (PSII, P689) fluorescence emission at a temperature of 77 K. The observed magnetic perturbation that affects the thylakoid photon capture circuitry was also found to be associated with the bio-energetic machinery of the thylakoid membranes. At normal pH, SMF causes an enhancement of PSI fluorescence emission intensity (P723/P689 > 1), followed by a slow relaxation on the removal of SMF. The enhancement of the PSI fluorescence intensity also occurs under no-field condition, if either the pH of the medium is lowered, or protonophores, such as carbonyl cyanide chlorophenylhydrazine or nigericin are added (P723/P689 ≥ 2). If SMF was applied under such a low pH condition or in the presence of protonophore, a reverse effect, particularly, a reduction of the enhanced PSI emission was observed. Because SMF is essentially equivalent to a spin perturbation, the observed effects can be explained in terms of spin re-organization, illustrating a memory effect via membrane re-alignment and assembly. The mimicry of conventional uncouplers by SMF is also notable; the essential difference being the reversibility and manoeuvrability of the latter (SMF). Finally, the effect implies numerous possibilities of externally regulating the photon capture and proton circulation in the thylakoid membranes using controlled SMF.

Graphical abstract: Static magnetic field (SMF) sensing of the P723/P689 photosynthetic complex

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Supplementary files

Article information


Submitted
30 Jul 2014
Accepted
16 Sep 2014
First published
18 Sep 2014

Photochem. Photobiol. Sci., 2014,13, 1719-1729
Article type
Paper
Author version available

Static magnetic field (SMF) sensing of the P723/P689 photosynthetic complex

A. Bhattacharya, M. Chakraborty, S. O. Raja, A. Ghosh, M. Dasgupta and A. Kr. Dasgupta, Photochem. Photobiol. Sci., 2014, 13, 1719
DOI: 10.1039/C4PP00295D

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