Arg24 and 26 of the D2 protein are important for photosystem II assembly and plastoquinol exchange in Synechocystis sp. PCC 6803.

Autor: Biswas S; Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand., Khaing EP; Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand., Zhong V; Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand., Eaton-Rye JJ; Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand. Electronic address: julian.eaton-rye@otago.ac.nz.
Jazyk: angličtina
Zdroj: Biochimica et biophysica acta. Bioenergetics [Biochim Biophys Acta Bioenerg] 2024 Nov 01; Vol. 1865 (4), pp. 149150. Date of Electronic Publication: 2024 Jun 19.
DOI: 10.1016/j.bbabio.2024.149150
Abstrakt: Photosystem II (PS II) assembly is a stepwise process involving preassembly complexes or modules focused around four core PS II proteins. The current model of PS II assembly in cyanobacteria is derived from studies involving the deletion of one or more of these core subunits. Such deletions may destabilize other PS II assembly intermediates, making constructing a clear picture of the intermediate events difficult. Information on plastoquinone exchange pathways operating within PS II is also unclear and relies heavily on computer-aided simulations. Deletion of PsbX in [S. Biswas, J.J. Eaton-Rye, Biochim. Biophys. Acta - Bioenerg. 1863 (2022) 148519] suggested modified Q B binding in PS II lacking this subunit. This study has indicated the phenotype of the ∆PsbX mutant arose by disrupting a conserved hydrogen bond between PsbX and the D2 (PsbD) protein. We mutated two conserved arginine residues (D2:Arg24 and D2:Arg26) to further understand the observations made with the ∆PsbX mutant. Mutating Arg24 disrupted the interaction between PsbX and D2, replicating the high-light sensitivity and altered fluorescence decay kinetics observed in the ∆PsbX strain. The Arg26 residue, on the other hand, was more important for either PS II assembly or for stabilizing the fully assembled complex. The effects of mutating both arginine residues to alanine or aspartate were severe enough to render the corresponding double mutants non-photoautotrophic. Our study furthers our knowledge of the amino-acid interactions stabilizing plastoquinone-exchange pathways while providing a platform to study PS II assembly and repair without the actual deletion of any proteins.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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