{"title":"Current analysis of cations substitution in the oxygen-evolving complex of photosystem II.","authors":"Boris Semin, Aleksey Loktyushkin, Elena Lovyagina","doi":"10.1007/s12551-024-01186-6","DOIUrl":null,"url":null,"abstract":"<p><p>Water oxidation in photosystem II (PSII) is performed by the oxygen-evolving complex Mn<sub>4</sub>CaO<sub>5</sub> which can be extracted from PSII and then reconstructed using exogenous cations Mn(II) and Ca<sup>2+</sup>. The binding efficiency of other cations to the Mn-binding sites in Mn-depleted PSII was investigated without any positive results. At the same time, a study of the Fe cations interaction with Mn-binding sites showed that it binds at a level comparable with the binding of Mn cations. Binding of Fe(II) cations first requires its light-dependent oxidation. In general, the interaction of Fe(II) with Mn-depleted PSII has a number of features similar to the two-quantum model of photoactivation of the complex with the release of oxygen. Interestingly, incubation of Ca-depleted PSII with Fe(II) cations under certain conditions is accompanied by the formation of a chimeric cluster Mn/Fe in the oxygen-evolving complex. PSII with the cluster 2Mn2Fe was found to be capable of water oxidation, but only to the H<sub>2</sub>O<sub>2</sub> intermediate. However, the cluster 3Mn1Fe can oxidize water to O<sub>2</sub> with an efficiency about 25% of the original in the absence of extrinsic proteins PsbQ and PsbP. In the presence of these proteins, the efficiency of O<sub>2</sub> evolution can reach 80% of the original when adding exogenous Ca<sup>2+</sup>. In this review, we summarized information on the formation of chimeric Mn-Fe clusters in the oxygen-evolving complex. The data cited may be useful for detailing the mechanism of water oxidation.</p>","PeriodicalId":9094,"journal":{"name":"Biophysical reviews","volume":"16 2","pages":"237-247"},"PeriodicalIF":4.9000,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11078907/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biophysical reviews","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1007/s12551-024-01186-6","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/4/1 0:00:00","PubModel":"eCollection","JCR":"Q1","JCRName":"BIOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Water oxidation in photosystem II (PSII) is performed by the oxygen-evolving complex Mn4CaO5 which can be extracted from PSII and then reconstructed using exogenous cations Mn(II) and Ca2+. The binding efficiency of other cations to the Mn-binding sites in Mn-depleted PSII was investigated without any positive results. At the same time, a study of the Fe cations interaction with Mn-binding sites showed that it binds at a level comparable with the binding of Mn cations. Binding of Fe(II) cations first requires its light-dependent oxidation. In general, the interaction of Fe(II) with Mn-depleted PSII has a number of features similar to the two-quantum model of photoactivation of the complex with the release of oxygen. Interestingly, incubation of Ca-depleted PSII with Fe(II) cations under certain conditions is accompanied by the formation of a chimeric cluster Mn/Fe in the oxygen-evolving complex. PSII with the cluster 2Mn2Fe was found to be capable of water oxidation, but only to the H2O2 intermediate. However, the cluster 3Mn1Fe can oxidize water to O2 with an efficiency about 25% of the original in the absence of extrinsic proteins PsbQ and PsbP. In the presence of these proteins, the efficiency of O2 evolution can reach 80% of the original when adding exogenous Ca2+. In this review, we summarized information on the formation of chimeric Mn-Fe clusters in the oxygen-evolving complex. The data cited may be useful for detailing the mechanism of water oxidation.
期刊介绍:
Biophysical Reviews aims to publish critical and timely reviews from key figures in the field of biophysics. The bulk of the reviews that are currently published are from invited authors, but the journal is also open for non-solicited reviews. Interested authors are encouraged to discuss the possibility of contributing a review with the Editor-in-Chief prior to submission. Through publishing reviews on biophysics, the editors of the journal hope to illustrate the great power and potential of physical techniques in the biological sciences, they aim to stimulate the discussion and promote further research and would like to educate and enthuse basic researcher scientists and students of biophysics. Biophysical Reviews covers the entire field of biophysics, generally defined as the science of describing and defining biological phenomenon using the concepts and the techniques of physics. This includes but is not limited by such areas as: - Bioinformatics - Biophysical methods and instrumentation - Medical biophysics - Biosystems - Cell biophysics and organization - Macromolecules: dynamics, structures and interactions - Single molecule biophysics - Membrane biophysics, channels and transportation