Elevation of photosystem II thermal stability at pH 5.7 due to the structural transition in the oxygen-evolving complex

Autor:	Boris K. Semin, E.R. Lovyagina
Rok vydání:	2021
Předmět:	Photosystem II Inorganic chemistry Oxygen evolution chemistry.chemical_element macromolecular substances Plant Science Manganese Oxygen-evolving complex Biology Electron transport chain Redox Membrane chemistry Thermal stability Agronomy and Crop Science Biotechnology
Zdroj:	Journal of Plant Biochemistry and Biotechnology. 31:440-445
ISSN:	0974-1275 0971-7811
DOI:	10.1007/s13562-021-00693-x
Popis:	In the presented work, a comparative study of the photosystem II (PSII) preparations resistance to elevated temperatures at pH 6.5 and 5.7 was carried out. The native and Ca-depleted PSII are completely inactivated (oxygen evolution and 2,6-dichlorophenolindophenol reduction) at 50 °C in buffer with pH 6.5. Inactivation is determined mainly by destruction of manganese cluster in the oxygen-evolving complex (OEC) since the electron-transport chain in the Mn-depleted PSII is more resistant to the heat treatment. We found that PSII membranes suspended in buffer with pH 5.7 are less sensitive to heat stress (50 °C) than the samples at pH 6.5. Residual rate of electron transport was about 22% and 3% respectively after heat treatment. We suggest that the increasing of the OEC resistance to the heat stress at pH 5.7 is determined by a pH-dependent change of the OEC manganese cations redox potential.
Databáze:	OpenAIRE
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