Alteration of the structure and function of photosystem I by Pb2
•Pb2+ modified protein structure in PSI submembrane fractions.•Binding constant, binding ratio and binding site of Pb2+ were determined.•An inhibitory site at or near plastocyanine is proposed. The toxic effects of Pb2+ on photosynthetic electron transport were studied in photosystem I (PSI) submemb...
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Published in | Journal of photochemistry and photobiology. B, Biology Vol. 123; pp. 41 - 47 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Switzerland
Elsevier B.V
05.06.2013
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Subjects | |
Online Access | Get full text |
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Summary: | •Pb2+ modified protein structure in PSI submembrane fractions.•Binding constant, binding ratio and binding site of Pb2+ were determined.•An inhibitory site at or near plastocyanine is proposed.
The toxic effects of Pb2+ on photosynthetic electron transport were studied in photosystem I (PSI) submembrane fractions isolated from spinach. Structural and spectroscopic analysis using FTIR, fluorescence and X-ray photoelectron spectroscopy (XPS) showed that Pb2+ binds with proteins via oxygen and nitrogen atoms with an overall binding constant of KPb-PSI=4.9×103 (±0.2) M−1 and the number of bound Pb2+ cation was 0.9 per PSI complex. Pb2+ binding altered the protein conformation indicating a partial protein destabilization. Electron transport and P700 photooxidation/reduction measurements showed that the interaction of Pb2+ cations with PSI produced a donor side limitation of electron transport presumably due to Pb2+ binding to or in the vicinity of plastocyanin. |
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ISSN: | 1011-1344 1873-2682 |
DOI: | 10.1016/j.jphotobiol.2013.03.010 |