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- Title
Mechanism of action of anions on the electron transport chain in thylakoid membranes of higher plants.
- Authors
Singh-Rawal, Pooja; Zsiros, Ottó; Győző Garab, Sudhakar Bharti; Jajoo, Anjana
- Abstract
With an aim to improve our understanding of the mechanisms behind specific anion effects in biological membranes, we have studied the effects of sodium salts of anions of varying valency in thylakoid membranes. Rates of electron transport of PS II and PS I, 77K fluorescence emission and excitation spectra, cyclic electron flow around PS I and circular dichroism (CD) spectra were measured in thylakoid membranes in order to elucidate a general mechanism of action of inorganic anions on photosynthetic electron transport chain. Re-distribution of absorbed excitation energy has been observed as a signature effect of inorganic anions. In the presence of anions, such as nitrite, sulphate and phosphate, distribution of absorbed excitation energy was found to be more in favor of Photosystem I (PS I). The amount of energy distributed towards PS I depended on the valency of the anion. In this paper, we propose for the first time that energy re-distribution and its valence dependence may not be the effect of anions per se. The entry of negative charge (anion) is accompanied by influx of positive charge (protons) to maintain a balance of charge across the thylakoid membranes . As reflected by the CD spectra, the observed energy re-distribution could be a result of structural rearrangements of the protein complexes of PS II caused by changes in the ionic environment of the thylakoid lumen.
- Subjects
ANIONS; ELECTRON transport; THYLAKOIDS; PLANT membranes; BIOLOGICAL membranes
- Publication
Journal of Bioenergetics & Biomembranes, 2011, Vol 43, Issue 2, p195
- ISSN
0145-479X
- Publication type
Article
- DOI
10.1007/s10863-011-9346-7