vestnik-bio-msuВестник Московского университета. Серия 16. БиологияVestnik Moskovskogo universiteta. Seriya 16. Biologiya0137-0952Lomonosov Moscow State University, School of Biology10.55959/MSU0137-0952-16-80-1-2vestnik-bio-msu-1494Research ArticleОригинальные исследованияТемновое химическое блокирование высокоаффинного Mn-связывающего участка фотосистемы 2 катионами Fe(II)Dark chemical blocking of the high-affinity Mn-binding site of photosystem II by Fe(II) cationshttps://orcid.org/0000-0002-3586-0575ЛовягинаЕ. Р.LovyaginaE. R.

Ловягина Елена Рудольфовна – канд. биол. наук, ст. науч. сотр. кафедры,

119234, г. Москва, Ленинские горы, д. 1, стр. 12.

1–12, Leninskie gory, Moscow, 119234.

elena.lovyagina@gmail.comhttps://orcid.org/0000-0002-9082-1966ЛоктюшкинА. В.LoktyushkinA. V.

Локтюшкин Алексей Владимирович – канд. биол. наук, доц. кафедры,

119234, г. Москва, Ленинские горы, д. 1, стр. 12.

1–12, Leninskie gory, Moscow, 119234.

allokt@gmail.comhttps://orcid.org/0000-0001-6877-2283ВасильевН. С.VasilievN. S.

Васильев Никита Сергеевич – инженер кафедры,

119234, г. Москва, Ленинские горы, д. 1, стр. 12.

1–12, Leninskie gory, Moscow, 119234.

nik_vasil@mail.ruhttps://orcid.org/0000-0002-0058-2798СеминБ. К.SeminB. K.

Семин Борис Константинович – докт. биол. наук, вед. науч. сотр. кафедры,

119234, г. Москва, Ленинские горы, д. 1, стр. 12.

1–12, Leninskie gory, Moscow, 119234.

semin@biophys.msu.ruМосковский государственный университет имени М.В. Ломоносова, биологический факультет, Кафедра биофизикиРоссияLomonosov Moscow State University, School of Biology, Department of BiophysicsRussian Federation2025290620258011117Copyright © Ловягина Е.Р., Локтюшкин А.В., Васильев Н.С., Семин Б.К., 20252025Ловягина Е.Р., Локтюшкин А.В., Васильев Н.С., Семин Б.К.Lovyagina E.R., Loktyushkin A.V., Vasiliev N.S., Semin B.K.Данная работа распространяется под лицензией Creative Commons Attribution 4.0.This work is licensed under a Creative Commons Attribution 4.0 License.https://vestnik-bio-msu.elpub.ru/jour/article/view/1494

Связывание катиона Fe(II) c высокоаффинным Mn-связывающим участком (ВАУ) фотосистемы 2 без кислород-выделяющего комплекса (ФС2(-Мn)) состоит из нескольких этапов – высоко-специфическая ассоциация катиона Fe(II) с ВАУ, окисление связанного катиона радикалом тирозина YZ●, генерируемым в результате поглощения кванта света первичным донором Р680 и разделения зарядов в реакционном центре, прочное связывание катиона Fe(III) c ВАУ, что приводит к блокированию (фотохимическому) ВАУ. В настоящей работе мы показали, что блокирование ВАУ катионом Fe может быть достигнуто не только фотохимическим способом, но и химическим: слабо связанный с ВАУ катион Fe(II) может быть окислен H2O2, что приводит к образованию Fe(III) и блокированию им ВАУ в результате прочного связывания. Однако эффективность химического блокирования существенно меньше фотохимического. Этот факт свидетельствует о том, что фотохимическое блокирование является не одноквантовым, а, по крайней мере, двухквантовым процессом. Полученные данные свидетельствуют в пользу двухквантового механизма физиологически очень важного процесса – фотоактивации (реконструкция марганцевого кластера в частицах ФС2(-Мn) в процессе их инкубации при освещении с катионами Mn(II)).

Binding of Fe(II) iron cation to high-affinity Mn-binding site (HAS) of photosystem II without oxygen-evolving complex (PSII(-Mn)) consists of several steps – a highly specific association of the Fe(II) cation with the HAS, oxidation of the bound cation with the tyrosine radical YZ●, generated as a result of light absorption by the primary donor P680 and charge separation in the reaction center, strong binding of the Fe(III) cation with HAS, which leads to HAS blocking (photochemical) with an iron cation. In the present work, we have shown that blocking HAS with an iron cation can be achieved not only by a photochemical process, but also by a chemical one: the Fe(II) cation weakly bound to HAS can be oxidized by hydrogen peroxide, which leads to the formation of Fe(III) and blocking of HAS by oxidized Fe cation as a result of strong binding. However, the effectiveness of chemical blocking is less than photochemical. This fact indicates that photochemical blocking is not a single quantum, but at least a two-quantum process. The data obtained indicate the two-quantum mechanism of a physiologically very important reaction - photoactivation (reconstruction of the manganese cluster in PSII(-Mn) particles during their incubation with Mn(II) cations).

фотосистема 2фотоактивациякислород-выделяющий комплексмарганец-связывающий участокжелезопероксид водородаphotosystem IIphotoactivationoxygen-evolving complexmanganese-binding siteironhydrogen peroxideИсследование выполнено в рамках государственного задания МГУ имени М.В. Ломоносова.The study was conducted under the state assignment of Lomonosov Moscow State University.ReferencesJärvi S., Suorsa M., Aro E.M. Photosystem II repair in plant chloroplasts — regulation, assisting proteins and shared components with photosystem II biogenesis. Biochim. Biophys. Acta Bioenergetics. 2015;1847(9):900−909.Järvi S., Suorsa M., Aro E.M. Photosystem II repair in plant chloroplasts — regulation, assisting proteins and shared components with photosystem II biogenesis. Biochim. Biophys. Acta Bioenergetics. 2015;1847(9):900−909.Oliver N., Avramov A.P., Nürnberg D.J., Dau H., Burnap R.L. From manganese oxidation to water oxidation: assembly and evolution of the water-splitting complex in photosystem II. Photosynth. Res. 2022;152(2):107−133.Oliver N., Avramov A.P., Nürnberg D.J., Dau H., Burnap R.L. From manganese oxidation to water oxidation: assembly and evolution of the water-splitting complex in photosystem II. Photosynth. Res. 2022;152(2):107−133.Semin B.K., Ivanov I.I., Rubin A.B., Parak F. Highspecific binding of Fe(II) at the Mn-binding site in Mndepleted PSII membranes from spinach. FEBS Lett. 1995;375(3):223−226.Semin B.K., Ivanov I.I., Rubin A.B., Parak F. Highspecific binding of Fe(II) at the Mn-binding site in Mndepleted PSII membranes from spinach. FEBS Lett. 1995;375(3):223−226.Semin B.K., Ghirardi M.L., Seibert M. Blocking of electron donation by Mn(II) to YZ• following incubation of Mn-depleted photosystem II membranes with Fe(II) in the light. Biochemistry. 2002;41(18):5854−5864.Semin B.K., Ghirardi M.L., Seibert M. Blocking of electron donation by Mn(II) to YZ• following incubation of Mn-depleted photosystem II membranes with Fe(II) in the light. Biochemistry. 2002;41(18):5854−5864.Semin B., Loktyushkin, A., Lovyagina E. Current analysis of cations substitution in the oxygen-evolving complex of photosystem II. Biophys. Rev. 2024;16(2):237−247.Semin B., Loktyushkin, A., Lovyagina E. Current analysis of cations substitution in the oxygen-evolving complex of photosystem II. Biophys. Rev. 2024;16(2):237−247.Semin B.K., Seibert M. Substituting Fe for two of the four Mn ions in photosystem II — effects on wateroxidation. J. Bioenerg. Biomembr. 2016;48(3):227−240.Semin B.K., Seibert M. Substituting Fe for two of the four Mn ions in photosystem II — effects on wateroxidation. J. Bioenerg. Biomembr. 2016;48(3):227−240.Semin B.K., Davletshina L.N., Seibert M., Rubin A.B. Creation of a 3Mn/1Fe cluster in the oxygen-evol- ving complex of photosystem II and investigation of its functional activity. J. Photochem. Photobiol. B 2018;178:192–200.Semin B.K., Davletshina L.N., Seibert M., Rubin A.B. Creation of a 3Mn/1Fe cluster in the oxygen-evol- ving complex of photosystem II and investigation of its functional activity. J. Photochem. Photobiol. B 2018;178:192–200.Widdel F., Schnell S., Heising S., Ehrenreich A., Assmus B., Schink B. Ferrous iron oxidation by anoxygenic phototrophic bacteria. Nature. 1993; 362(6423):834−836.Widdel F., Schnell S., Heising S., Ehrenreich A., Assmus B., Schink B. Ferrous iron oxidation by anoxygenic phototrophic bacteria. Nature. 1993; 362(6423):834−836.Ghanotakis D.F., Babcock G.T. Hydroxylamine as an inhibitor between Z and P680 in photosystem II. FEBS Lett. 1983;153(1):231−234.Ghanotakis D.F., Babcock G.T. Hydroxylamine as an inhibitor between Z and P680 in photosystem II. FEBS Lett. 1983;153(1):231−234.Porra R.J., Thompson W.A., Kriedemann P.E. Determination of accurate extinction coefficients and simultaneous equations for assaying chlorophylls a and b extracted with four different solvents: verification of the concentration of chlorophyll standards by atomic absorption spectroscopy. Biochim. Biophys. Acta Bioenerg. 1989;975(3):384–394.Porra R.J., Thompson W.A., Kriedemann P.E. Determination of accurate extinction coefficients and simultaneous equations for assaying chlorophylls a and b extracted with four different solvents: verification of the concentration of chlorophyll standards by atomic absorption spectroscopy. Biochim. Biophys. Acta Bioenerg. 1989;975(3):384–394.Armstrong J.M.D. The molar extinction coefficient of 2,6-dichlorophenol indophenol. Biochim. Biophys. Acta Gen. Subj. 1964;86(1):194−197.Armstrong J.M.D. The molar extinction coefficient of 2,6-dichlorophenol indophenol. Biochim. Biophys. Acta Gen. Subj. 1964;86(1):194−197.Ono T.A., Mino H. Unique binding site for Mn2+ ion responsible for reducing an oxidized YZ tyrosine in manganese-depleted photosystem II membranes. Biochemistry 1999;38(27):8778–8785.Ono T.A., Mino H. Unique binding site for Mn2+ ion responsible for reducing an oxidized YZ tyrosine in manganese-depleted photosystem II membranes. Biochemistry 1999;38(27):8778–8785.Petrova A., Mamedov M., Ivanov B., Semenov A., Kozuleva M. Effect of artificial redox mediators on the photoinduced oxygen reduction by photosystem I complexes. Photosynth. Res. 2018;137(3):421−429.Petrova A., Mamedov M., Ivanov B., Semenov A., Kozuleva M. Effect of artificial redox mediators on the photoinduced oxygen reduction by photosystem I complexes. Photosynth. Res. 2018;137(3):421−429.Jahn B., Jonasson N.S., Hu H., Singer H., Pol A., Good N.M., Op den Camp H.J.M., Martinez-Gomez N.C., Daumann L.J. Understanding the chemistry of the artificial electron acceptors PES, PMS, DCPIP and Wurster’s Blue in methanol dehydrogenase assays. J. Biol. Inorg. Chem. 2020;25(2):199−212.Jahn B., Jonasson N.S., Hu H., Singer H., Pol A., Good N.M., Op den Camp H.J.M., Martinez-Gomez N.C., Daumann L.J. Understanding the chemistry of the artificial electron acceptors PES, PMS, DCPIP and Wurster’s Blue in methanol dehydrogenase assays. J. Biol. Inorg. Chem. 2020;25(2):199−212.Inoué H., Akahori H., Noguchi M. Activation of electron donation from hydrogen peroxide by manganese in non-oxygen evolving photosystem II particles. Plant Cell Physiol. 1987;28(7):1339–1343.Inoué H., Akahori H., Noguchi M. Activation of electron donation from hydrogen peroxide by manganese in non-oxygen evolving photosystem II particles. Plant Cell Physiol. 1987;28(7):1339–1343.Inoué H., Wada T. Requirement of manganese for electron donation of hydrogen peroxide in photosystem II reaction center complex. Plant Cell Physiol. 1987;28(5):767–773.Inoué H., Wada T. Requirement of manganese for electron donation of hydrogen peroxide in photosystem II reaction center complex. Plant Cell Physiol. 1987;28(5):767–773.Semin B.K., Davletshina L.N., Goryachev S.N., Seibert M. Ca2+ effects on Fe(II) interactions with Mn-binding sites in Mn-depleted oxygen-evolving complexes of photosystem II and on Fe replacement of Mn in Mn-containing, Ca-depleted complexes. Photosynth. Res. 2021;147(2):229–237.Semin B.K., Davletshina L.N., Goryachev S.N., Seibert M. Ca2+ effects on Fe(II) interactions with Mn-binding sites in Mn-depleted oxygen-evolving complexes of photosystem II and on Fe replacement of Mn in Mn-containing, Ca-depleted complexes. Photosynth. Res. 2021;147(2):229–237.Umena Y., Kawakami K., Shen J.-R., Kamiya N. Crystal structure of oxygen evolving photosystem II at a resolution of 1.9 Å. Nature. 2011;473(7345):55–60.Umena Y., Kawakami K., Shen J.-R., Kamiya N. Crystal structure of oxygen evolving photosystem II at a resolution of 1.9 Å. Nature. 2011;473(7345):55–60.

The authors declare that there are no conflicts of interest present.