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Zharmukhamedov SK, Shabanova MS, Rodionova MV, Huseynova IM, Karacan MS, Karacan N, Aşık KB, Kreslavski VD, Alwasel S, Allakhverdiev SI. Effects of Novel Photosynthetic Inhibitor [CuL2]Br2 Complex on Photosystem II Activity in Spinach. Cells 2022; 11:cells11172680. [PMID: 36078088 PMCID: PMC9455146 DOI: 10.3390/cells11172680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/25/2022] Open
Abstract
The effects of the novel [CuL2]Br2 complex (L = bis{4H-1,3,5-triazino [2,1-b]benzothiazole-2-amine,4-(2-imidazole)}copper(II) bromide complex) on the photosystem II (PSII) activity of PSII membranes isolated from spinach were studied. The absence of photosynthetic oxygen evolution by PSII membranes without artificial electron acceptors, but in the presence of [CuL2]Br2, has shown that it is not able to act as a PSII electron acceptor. In the presence of artificial electron acceptors, [CuL2]Br2 inhibits photosynthetic oxygen evolution. [CuL2]Br2 also suppresses the photoinduced changes of the PSII chlorophyll fluorescence yield (FV) related to the photoreduction of the primary quinone electron acceptor, QA. The inhibition of both characteristic PSII reactions depends on [CuL2]Br2 concentration. At all studied concentrations of [CuL2]Br2, the decrease in the FM level occurs exclusively due to a decrease in Fv. [CuL2]Br2 causes neither changes in the F0 level nor the retardation of the photoinduced rise in FM, which characterizes the efficiency of the electron supply from the donor-side components to QA through the PSII reaction center (RC). Artificial electron donors (sodium ascorbate, DPC, Mn2+) do not cancel the inhibitory effect of [CuL2]Br2. The dependences of the inhibitory efficiency of the studied reactions of PSII on [CuL2]Br2 complex concentration practically coincide. The inhibition constant Ki is about 16 µM, and logKi is 4.8. As [CuL2]Br2 does not change the aromatic amino acids’ intrinsic fluorescence of the PSII protein components, it can be proposed that [CuL2]Br2 has no significant effect on the native state of PSII proteins. The results obtained in the present study are compared to the literature data concerning the inhibitory effects of PSII Cu(II) aqua ions and Cu(II)-organic complexes.
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Affiliation(s)
- Sergey K. Zharmukhamedov
- Institute of Basic Biological Problems, FRC PSCBR RAS, 142290 Pushchino, Russia
- Correspondence: (S.K.Z.); (S.I.A.)
| | - Mehriban S. Shabanova
- Bionanotechnology Laboratory, Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, AZ1073 Baku, Azerbaijan
| | - Margarita V. Rodionova
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, 127276 Moscow, Russia
| | - Irada M. Huseynova
- Bionanotechnology Laboratory, Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, AZ1073 Baku, Azerbaijan
| | - Mehmet Sayım Karacan
- Department of Chemistry, Science Faculty, Gazi University, Teknikokullar, Ankara 06500, Turkey
| | - Nurcan Karacan
- Department of Chemistry, Science Faculty, Gazi University, Teknikokullar, Ankara 06500, Turkey
| | - Kübra Begüm Aşık
- Department of Chemistry, Science Faculty, Gazi University, Teknikokullar, Ankara 06500, Turkey
| | | | - Saleh Alwasel
- College of Science, King Saud University, Riyadh 12372, Saudi Arabia
| | - Suleyman I. Allakhverdiev
- Institute of Basic Biological Problems, FRC PSCBR RAS, 142290 Pushchino, Russia
- Bionanotechnology Laboratory, Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, AZ1073 Baku, Azerbaijan
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, 127276 Moscow, Russia
- Department of Plant Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Leninskie Gory 1-12, 119991 Moscow, Russia
- Correspondence: (S.K.Z.); (S.I.A.)
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Battaglino B, Grinzato A, Pagliano C. Binding Properties of Photosynthetic Herbicides with the Q B Site of the D1 Protein in Plant Photosystem II: A Combined Functional and Molecular Docking Study. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10081501. [PMID: 34451546 PMCID: PMC8398153 DOI: 10.3390/plants10081501] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/13/2021] [Accepted: 07/20/2021] [Indexed: 05/07/2023]
Abstract
Photosystem II (PSII) is a multi-subunit enzymatic complex embedded in the thylakoid membranes responsible for the primary photosynthetic reactions vital for plants. Many herbicides used for weed control inhibit PSII by interfering with the photosynthetic electron transport at the level of the D1 protein, through competition with the native plastoquinone for the QB site. Molecular details of the interaction of these herbicides in the D1 QB site remain to be elucidated in plants. Here, we investigated the inhibitory effect on plant PSII of the PSII-inhibiting herbicides diuron, metobromuron, bentazon, terbuthylazine and metribuzin. We combined analysis of OJIP chlorophyll fluorescence kinetics and PSII activity assays performed on thylakoid membranes isolated from pea plants with molecular docking using the high-resolution PSII structure recently solved from the same plant. Both approaches showed for terbuthylazine, metribuzin and diuron the highest affinity for the D1 QB site, with the latter two molecules forming hydrogen bonds with His215. Conversely, they revealed for bentazon the lowest PSII inhibitory effect accompanied by a general lack of specificity for the QB site and for metobromuron an intermediate behavior. These results represent valuable information for future design of more selective herbicides with enhanced QB binding affinities to be effective in reduced amounts.
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Affiliation(s)
- Beatrice Battaglino
- Applied Science and Technology Department—BioSolar Lab, Politecnico di Torino, Environment Park, Via Livorno 60, 10144 Torino, Italy;
| | - Alessandro Grinzato
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58 B, 35121 Padova, Italy;
| | - Cristina Pagliano
- Applied Science and Technology Department—BioSolar Lab, Politecnico di Torino, Environment Park, Via Livorno 60, 10144 Torino, Italy;
- Correspondence: ; Tel.: +39-0110904626
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Semelkova L, Konecna K, Paterova P, Kubicek V, Kunes J, Novakova L, Marek J, Naesens L, Pesko M, Kralova K, Dolezal M, Zitko J. Synthesis and Biological Evaluation of N-Alkyl-3-(alkylamino)-pyrazine-2-carboxamides. Molecules 2015; 20:8687-711. [PMID: 26007174 PMCID: PMC6272192 DOI: 10.3390/molecules20058687] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 05/08/2015] [Indexed: 01/23/2023] Open
Abstract
A series of N-alkyl-3-(alkylamino)pyrazine-2-carboxamides and their N-alkyl-3-chloropyrazine-2-carboxamide precursors were prepared. All compounds were characterized by analytical methods and tested for antimicrobial and antiviral activity. The antimycobacterial MIC values against Mycobacterium tuberculosis H37Rv of the most effective compounds, 3-(hexylamino)-, 3-(heptylamino)- and 3-(octylamino)-N-methyl-pyrazine-2-carboxamides 14‒16, was 25 μg/mL. The compounds inhibited photosystem 2 photosynthetic electron transport (PET) in spinach chloroplasts. This activity was strongly connected with the lipophilicity of the compounds. For effective PET inhibition longer alkyl chains in the 3-(alkylamino) substituent in the N-alkyl-3-(alkylamino)pyrazine-2-carboxamide molecule were more favourable than two shorter alkyl chains.
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Affiliation(s)
- Lucia Semelkova
- Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 50005, Czech Republic.
| | - Klara Konecna
- Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 50005, Czech Republic.
| | - Pavla Paterova
- Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 50005, Czech Republic.
| | - Vladimir Kubicek
- Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 50005, Czech Republic.
| | - Jiri Kunes
- Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 50005, Czech Republic.
| | - Lucie Novakova
- Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 50005, Czech Republic.
| | - Jan Marek
- Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 50005, Czech Republic.
| | - Lieve Naesens
- Laboratory of Virology and Chemotherapy, Rega Institute KU Leuven, Minderbroedersstraat 10, Leuven B-3000, Belgium.
| | - Matus Pesko
- Department of Environmental Ecology, Faculty of Natural Sciences, Comenius University, Mlynska Dolina CH-2, Bratislava 84215, Slovakia.
| | - Katarina Kralova
- Institute of Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska Dolina CH-2, Bratislava 84215, Slovakia.
| | - Martin Dolezal
- Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 50005, Czech Republic.
| | - Jan Zitko
- Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, Hradec Kralove 50005, Czech Republic.
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Castelfranco PA, Lu YK, Stemler AJ. Hypothesis: the peroxydicarbonic acid cycle in photosynthetic oxygen evolution. PHOTOSYNTHESIS RESEARCH 2007; 94:235-46. [PMID: 17484037 DOI: 10.1007/s11120-007-9134-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Accepted: 01/08/2007] [Indexed: 05/15/2023]
Abstract
Peroxydicarbonic acid (Podca), a proposed intermediate in photosynthetic oxygen evolution, was synthesized electrochemically. Consistent with literature descriptions of this compound, it was shown to be a highly reactive molecule, spontaneously hydrolyzed to H2O2, as well as susceptible to oxidative and reductive decomposition. In the presence of Mn2+ or Co2+, Podca was quickly broken down with release of O2. The liberation of O2, however, was partially suppressed at high O2 concentrations. In the presence of Ca-washed photosystem II-enriched membranes lacking extrinsic proteins, Podca was decomposed with the release of O2, but only under conditions favoring photosynthetic electron flow (light plus a Hill oxidant). A model is proposed that details how peroxydicarbonic acid could act as an oxygen-evolving intermediate. The hypothesis is consistent with the well-established Kok model and with recent findings related to the chemistry of oxygen evolution.
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Dolezal M, Palek L, Vinsova J, Buchta V, Jampilek J, Kralova K. Substituted pyrazinecarboxamides: synthesis and biological evaluation. Molecules 2006; 11:242-56. [PMID: 17962755 DOI: 10.3390/11040242] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 03/19/2006] [Accepted: 03/20/2006] [Indexed: 11/16/2022] Open
Abstract
Condensation of the corresponding chlorides of some substituted pyrazine-2-carboxylic acids (pyrazine-2-carboxylic acid, 6-chloropyrazine-2-carboxylic acid, 5-tert-butylpyrazine-2-carboxylic acid or 5-tert-butyl-6-chloropyrazine-2-carboxylic acid) with various ring-substituted aminothiazoles or anilines yielded a series of amides. The syntheses, analytical and spectroscopic data of thirty newly prepared compounds are presented. Structure-activity relationships between the chemical structures and the anti-mycobacterial, antifungal and photosynthesis-inhibiting activity of the evaluated compounds are discussed. 3,5-Bromo-4-hydroxyphenyl derivatives of substituted pyrazinecarboxylic acid, 16-18, have shown the highest activity against Mycobacterium tuberculosis H(37)Rv (54-72% inhibition). The highest antifungal effect against Trichophyton mentagrophytes, the most susceptible fungal strain tested, was found for 5-tert-butyl-6-chloro-N-(4-methyl-1,3-thiazol-2-yl)pyrazine-2-carboxamide (8, MIC =31.25 micromol x mL(-1)). The most active inhibitors of oxygen evolution rate in spinach Molecules 2006, 11,243 chloroplasts were the compounds 5-tert-butyl-6-chloro-N-(5-bromo-2-hydroxyphenyl)- pyrazine-2-carboxamide (27, IC(50) = 41.9 micromol x L(-1)) and 5-tert-butyl-6-chloro-N-(1,3- thiazol-2-yl)-pyrazine-2-carboxamide (4, IC50 = 49.5 micromol x L(-1)).
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Affiliation(s)
- Martin Dolezal
- Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic.
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Opletalová V, Pour M, Kuneš J, Buchta V, Silva L, Kráľová K, Chlupáčová M, Meltrová D, Peterka M, Posledníková M. Synthesis and Biological Evaluation of (E)-3-(Nitrophenyl)-1-(pyrazin-2-yl)prop-2-en-1-ones. ACTA ACUST UNITED AC 2006. [DOI: 10.1135/cccc20060044] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The title (E)-(3-nitrophenyl)-1-(pyrazin-2-yl)prop-2-en-1-ones were prepared by the Claisen- Schmidt condensation of acetylpyrazines and 2-nitro-, 3-nitro- and 4-nitrobenzaldehyde in pyridine using diethylamine as the catalyst. The compounds were bioassayed for in vitro antifungal, antimycobacterial and photosynthesis-inhibiting activity. The high potency of (E)-1-(5-tert-butylpyrazin-2-yl)-3-(4-nitrophenyl)prop-2-en-1-one againstMycobacterium tuberculosis(MIC 0.78 μg/ml) and moderate activities of several compounds againstTrichophyton mentagrophytesandCandidaspp. do not support the assumption that phenolic groups are essential for antimycobacterial and antifungal activity of chalcones and their analogues. In fact, the nitro-substituted compounds were superior to the previously described hydroxylated congeners with antimycobacterial activity (MIC ≥ 12.5 μg/ml). The compounds also reduced chlorophyll content in green algaChlorella vulgaris, and some of them inhibited photosynthetic electron transport in spinach chloroplasts as well. The photosynthesis-inhibiting activity of nitro derivatives was lower than that of the corresponding hydroxylated analogues.
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Bukhov NG, Egorova EA, Govindachary S, Carpentier R. Changes in polyphasic chlorophyll a fluorescence induction curve upon inhibition of donor or acceptor side of photosystem II in isolated thylakoids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2004; 1657:121-30. [PMID: 15238269 DOI: 10.1016/j.bbabio.2004.04.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2003] [Revised: 04/26/2004] [Accepted: 04/30/2004] [Indexed: 11/24/2022]
Abstract
The action of various inhibitors affecting the donor and acceptor sides of photosystem II (PSII) on the polyphasic rise of chlorophyll (Chl) fluorescence was studied in thylakoids isolated from pea leaves. Low concentrations of diuron and stigmatellin increased the magnitude of J-level of the Chl fluorescence rise. These concentrations barely affected electron transfer from PSII to PSI as revealed by the unchanged magnitude of the fast component (t(1/2) = 24 ms) of P700+ dark reduction. Higher concentrations of diuron and stigmatellin suppressed electron transport from PSII to PSI, which corresponded to the loss of thermal phase, the Chl fluorescence rise from J-level to the maximal, P-level. The effect of various concentrations of carbonylcyanide m-chlorophenylhydrazone (CCCP), which abolishes S-state cycle and binds at the plastoquinone site on QB, the secondary quinone acceptor PSII, on the Chl fluorescence rise was very similar to that of diuron and stigmatellin. Low concentrations of diuron, stigmatellin, or CCCP given on the background of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), which is shown to initiate the appearance of a distinct I-peak in the kinetics of Chl fluorescence rise measured in isolated thylakoids [BBA 1607 (2003) 91], increased J-step yield to I-step level and retarded Chl fluorescence rise from I-step to P-step. The increased J-step fluorescence rise caused by these three types of inhibitors is attributed to the suppression of the non-photochemical quenching of Chl fluorescence by [S2+ S3] states of the oxygen-evolving complex and oxidized P680, the primary donor of PSII reaction centers. In the contrary, the decreased fluorescence yield at P step (J-P, passing through I) is related to the persistence of a "plastoquinone"-type quenching owing to the limited availability of photochemically generated electron equivalents to reduce PQ pool in PSII centers where the S-state cycle of the donor side is modified by the inhibitor treatments.
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Affiliation(s)
- Nikolai G Bukhov
- Groupe de Recherche en Energie et Information Biomoléculaires, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada GA9 5H7
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Opletalová V, Hartl J, Patel A, Palát K, Buchta V. Ring substituted 3-phenyl-1-(2-pyrazinyl)-2-propen-1-ones as potential photosynthesis-inhibiting, antifungal and antimycobacterial agents. FARMACO (SOCIETA CHIMICA ITALIANA : 1989) 2002; 57:135-44. [PMID: 11902656 DOI: 10.1016/s0014-827x(01)01187-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Four series of ring substituted (E)-3-phenyl-1-(2-pyrazinyl)-2-propen-1-ones were prepared by means of modified Claisen-Schmidt condensation of acetylpyrazines with aromatic aldehydes. The structures were confirmed by elemental analysis, IR, 1H NMR and 13C NMR spectra. The compounds were tested for specific biological properties and some derivatives exhibited photosynthesis-inhibiting, antifungal and antimycobacterial properties. The most pronounced effects were observed with compounds substituted with phenolic groups. Ortho-hydroxyl substituted derivatives were more potent than the corresponding para-hydroxyl substituted analogues.
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Affiliation(s)
- Veronika Opletalová
- Department of Pharmaceutical Chemistry and Drug Control, Faculty of Pharmacy, Charles University in Prague, Hradec Králové, Czech Republic.
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Comparison of the decay of slow delayed luminescence in triazine-susceptible and -resistant biotypes of Erigeron canadensis L. FEBS Lett 2001. [DOI: 10.1016/0014-5793(86)80526-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Pistorius EK, Gau AE. A possible model for the organic prosthetic group of the water-splitting complex in the cyanobacterium Anacystis nidulans. FEBS Lett 2001. [DOI: 10.1016/0014-5793(86)80989-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Synthesis of 2-benzylthiopyridine-4-carbothioamide derivatives and their antimycobacterial, antifungal and photosynthesis-inhibiting activity. Eur J Med Chem 1999. [DOI: 10.1016/s0223-5234(99)80093-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Fluorescence quenching by plastoquinone in an oxygen-evolving photosystem-II-enriched preparation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1995. [DOI: 10.1016/1011-1344(95)07146-s] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Purcell M, Leroux GD, Carpentier R. Interaction of the electron donor diphenylcarbazide with the herbicide-binding niche of Photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(05)80133-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Carpentier R, Leblanc RM, Mimeault M. Photoacoustic detection of photosynthetic energy storage in Photosystem II submembrane fractions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1989. [DOI: 10.1016/s0005-2728(89)80345-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Vasil'ev IR, Matorin DN, Lyadsky VV, Venediktov PS. Multiple action sites for photosystem II herbicides as revealed by delayed fluorescence. PHOTOSYNTHESIS RESEARCH 1988; 15:33-39. [PMID: 24430790 DOI: 10.1007/bf00054986] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/1987] [Accepted: 08/04/1987] [Indexed: 06/03/2023]
Abstract
DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) at concentrations higher than 10 μM suppresses the second time range delayed fluorescence (DF) of pea chloroplasts, due to inhibition of the oxidizing side of photosystem II (PS II). The inhibition of the reducing side of PS II resulting in the suppression of millisecond DF takes place at much lower (∼0.01 μM) DCMU concentrations. The variation in the herbicide-affinities of the reducing and oxidizing sides of PS II is not the same for DCMU and phenol-type herbicides. The DCMU-affinity of the oxidizing side considerably increases and approximates that of the reducing side upon mild treatment of chloroplasts with oleic acid. Probably this is a result of some changes in the environment of the binding site at the oxidizing side. At DCMU concentrations higher than 1 mM, the chaotropic action of DCMU leads to the generation of millisecond luminescence which is not related to the functioning of the reaction centres.
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Affiliation(s)
- I R Vasil'ev
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 19899, Moscow, USSR
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Abstract
Measurements on the fluorescence induction of Triton X-100 extracted Photosystem II (PSII) particles confirmed the existence of the two sites of inhibition in PSII for the herbicide DCMU. The two sites were located on the reducing and oxidizing sides of PSII, respectively. The inhibition on the oxidizing side, unlike that on the reducing side which was of the "none or all" type, was found only to slow down the electron donation at low concentrations of DCMU. The results also suggested that the inhibitions of DCMU at these two sites were mutually exclusive, i.e., the binding on one site prevented the binding on the other site.
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Trebst A, Draber W. Inhibitors of photosystem II and the topology of the herbicide and QB binding polypeptide in the thylakoid membrane. PHOTOSYNTHESIS RESEARCH 1986; 10:381-92. [PMID: 24435386 DOI: 10.1007/bf00118304] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The folding through the thylakoid membrane of the D-1 herbicide binding polypeptide and of the homologous D-2 subunit of photosystem II is predicted from comparison of amino acid sequences and hydropathy index plots with the folding of the subunits L and M of a bacterial photosystem. As the functional amino acids involved in Q and Fe binding in the bacterial photosystem of R. viridis, as indicated by the X-ray structure, are conserved in the homologous D-1 and D-2 subunits of photosystem II, a detailed topology of the binding niche of QB and of herbicides on photosystem II is proposed. The model is supported by the observed amino acid changes in herbicide tolerant plants and algae. These changes are all in the binding domain on the matrix side of the D-1 polypeptide, and turn out to be of functional significance in the QB binding.New inhibitors of QB function are described. Their chemical structure, i.e. pyridones, quinolones, chromones and benzodiones, contains the features of the phenolic type herbicides. Their essential elements, π-charges at particular atoms, QSAR and steric requirements for optimal inhibitory potency are discussed and compared with the "classical" herbicides of the urea/triazine type.
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Affiliation(s)
- A Trebst
- Dept. of Biology, Ruhr-University Bochum, FRG
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20
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Carpentier R, Nakatani HY. Inhibitors affecting the oxidizing side of Photosystem II at the Ca2+- and Cl−-sensitive sites. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1985. [DOI: 10.1016/0005-2728(85)90011-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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