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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Malikova N. P., Eremeeva E. V., Gulnov D. V., Natashin P. V., Nemtseva E. V., Vysotski E. S.
Заглавие : Specific Activities of Hydromedusan Ca2+-Regulated Photoproteins
Место публикации : Photochem. Photobiol.: John Wiley and Sons Inc, 2021. - Article in press. - ISSN 00318655 (ISSN), DOI 10.1111/php.13556
Аннотация: Nowadays the recombinant Ca2+-regulated photoproteins originating from marine luminous organisms are widely applied to monitor calcium transients in living cells due to their ability to emit light on Ca2+ binding. Here we report the specific activities of the recombinant Ca2+-regulated photoproteins—aequorin from Aequorea victoria, obelins from Obelia longissima and Obelia geniculata, clytin from Clytia gregaria and mitrocomin from Mitrocoma cellularia. We demonstrate that along with bioluminescence spectra, kinetics of light signals and sensitivities to calcium, these photoproteins also differ in specific activities and consequently in quantum yields of bioluminescent reactions. The highest specific activities were found for obelins and mitrocomin, whereas those of aequorin and clytin were shown to be lower. To determine the factors influencing the variations in specific activities the fluorescence quantum yields for Ca2+-discharged photoproteins were measured and found to be quite different varying in the range of 0.16–0.36. We propose that distinctions in specific activities may result from different efficiencies of singlet excited state generation and different fluorescence quantum yields of coelenteramide bound within substrate-binding cavity. This in turn may be conditioned by variations in the amino acid environment of the substrate-binding cavities and hydrogen bond distances between key residues and atoms of 2-hydroperoxycoelenterazine. © 2021 American Society for Photobiology
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Eremeeva E. V., Jiang T., Malikova N. P., Li M., Vysotski E. S.
Заглавие : Bioluminescent properties of semi-synthetic obelin and aequorin activated by coelenterazine analogues with modifications of C-2, C-6, and C-8 substituents
Место публикации : Int. J. Mol. Sci.: MDPI AG, 2020. - Vol. 21, Is. 15. - Ст.5446. - С. 1-21. - ISSN 16616596 (ISSN), DOI 10.3390/ijms21155446
Аннотация: Ca2+-regulated photoproteins responsible for bioluminescence of a variety of marine organisms are single-chain globular proteins within the inner cavity of which the oxygenated coelenterazine, 2-hydroperoxycoelenterazine, is tightly bound. Alongside with native coelenterazine, photoproteins can also use its synthetic analogues as substrates to produce flash-type bioluminescence. However, information on the effect of modifications of various groups of coelenterazine and amino acid environment of the protein active site on the bioluminescent properties of the corresponding semi-synthetic photoproteins is fragmentary and often controversial. In this paper, we investigated the specific bioluminescence activity, light emission spectra, stopped-flow kinetics and sensitivity to calcium of the semi-synthetic aequorins and obelins activated by novel coelenterazine analogues and the recently reported coelenterazine derivatives. Several semi-synthetic photoproteins activated by the studied coelenterazine analogues displayed sufficient bioluminescence activities accompanied by various changes in the spectral and kinetic properties as well as in calcium sensitivity. The poor activity of certain semi-synthetic photoproteins might be attributed to instability of some coelenterazine analogues in solution and low efficiency of 2-hydroperoxy adduct formation. In most cases, semi-synthetic obelins and aequorins displayed different properties upon being activated by the same coelenterazine analogue. The results indicated that the OH-group at the C-6 phenyl ring of coelenterazine is important for the photoprotein bioluminescence and that the hydrogen-bond network around the substituent in position 6 of the imidazopyrazinone core could be the reason of different bioluminescence activities of aequorin and obelin with certain coelenterazine analogues. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ding B. -W., Eremeeva E. V., Vysotski E. S., Liu Y. -J.
Заглавие : Luminescence Activity Decreases When v-coelenterazine Replaces Coelenterazine in Calcium-Regulated Photoprotein—A Theoretical and Experimental Study
Место публикации : Photochem. Photobiol.: Blackwell Publishing Inc., 2020. - Article in press. - ISSN 00318655 (ISSN), DOI 10.1111/php.13280
Аннотация: Calcium-regulated photoproteins are found in at least five phyla of organisms. The light emitted by those photoproteins can be tuned by mutating the photoprotein and/or by modifying the substrate coelenterazine (CTZ). Thirty years ago, Shimomura observed that the luminescence activity of aequorin was dramatically reduced when the substrate CTZ was replaced by its analog v-CTZ. The latter is formed by adding a phenyl ring to the ?-conjugated moiety of CTZ. The decrease in luminescence activity has not been understood until now. In this paper, through combined quantum mechanics and molecular mechanics calculations as well as molecular dynamics simulations, we discovered the reason for this observation. Modification of the substrate changes the conformation of nearby aromatic residues and enhances the ?-? stacking interactions between the conjugated moiety of v-CTZ and the residues, which weakens the charge transfer to form light emitter and leads to a lower luminescence activity. The microenvironments of CTZ in obelin and in aequorin are very similar, so we predicted that the luminescence activity of obelin will also dramatically decrease when CTZ is replaced by v-CTZ. This prediction has received strong evidence from currently theoretical calculations and has been verified by experiments. © 2020 American Society for Photobiology
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ding, Bo-Wen, Eremeeva, Elena V., Vysotski, Eugene S., Liu, Ya-Jun
Заглавие : Luminescence Activity Decreases Whenv-coelenterazine Replaces Coelenterazine in Calcium-Regulated Photoprotein-A Theoretical and Experimental Study
Колич.характеристики :14 с
Коллективы : National Natural Science Foundation of ChinaNational Natural Science Foundation of China [21911530094, 21673020, 21973005]; RFBRRussian Foundation for Basic Research (RFBR) [19-54-53004, 20-54-53011]; China Postdoctoral Science FoundationChina Postdoctoral Science Foundation [2018M630100]
Место публикации : Photochem. Photobiol.: WILEY, 2020. - Article in press. - ISSN 0031-8655, DOI 10.1111/php.13280. - ISSN 1751-1097(eISSN)
Примечания : Cited References:68. - This study was sponsored by the National Natural Science Foundation of China (Grant No. 21911530094, 21673020 and 21973005) and RFBR (Grant No. 19-54-53004 and 20-54-53011). Ding also thank the support from the China Postdoctoral Science Foundation (Grant No. 2018M630100).
Предметные рубрики: RECOMBINANT SEMISYNTHETIC AEQUORINS
OBELIN BIOLUMINESCENCE
MECHANISTIC
Аннотация: Calcium-regulated photoproteins are found in at least five phyla of organisms. The light emitted by those photoproteins can be tuned by mutating the photoprotein and/or by modifying the substrate coelenterazine (CTZ). Thirty years ago, Shimomura observed that the luminescence activity of aequorin was dramatically reduced when the substrate CTZ was replaced by its analogv-CTZ. The latter is formed by adding a phenyl ring to the pi-conjugated moiety of CTZ. The decrease in luminescence activity has not been understood until now. In this paper, through combined quantum mechanics and molecular mechanics calculations as well as molecular dynamics simulations, we discovered the reason for this observation. Modification of the substrate changes the conformation of nearby aromatic residues and enhances the pi-pi stacking interactions between the conjugated moiety ofv-CTZ and the residues, which weakens the charge transfer to form light emitter and leads to a lower luminescence activity. The microenvironments of CTZ in obelin and in aequorin are very similar, so we predicted that the luminescence activity of obelin will also dramatically decrease when CTZ is replaced byv-CTZ. This prediction has received strong evidence from currently theoretical calculations and has been verified by experiments.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bakayan, Adil, Picaud, Sandrine, Malikova, Natalia P., Tricoire, Ludovic, Lambolez, Bertrand, Vysotski, Eugene S., Peyrieras, Nadine
Заглавие : RedquorinXS Mutants with Enhanced Calcium Sensitivity and Bioluminescence Output Efficiently Report Cellular and Neuronal Network Activities
Колич.характеристики :20 с
Коллективы : Centre National de la Recherche ScientifiqueCentre National de la Recherche Scientifique (CNRS); Agence Nationale de la RechercheFrench National Research Agency (ANR) [ANR-10-INBS-04, ANR-11-EQPX-029]; Fondation pour la Recherche sur le Cerveau/Rotary Club de France; RFBRRussian Foundation for Basic Research (RFBR) [20-04-00085]
Место публикации : Int. J. Mol. Sci.: MDPI, 2020. - Vol. 21, Is. 21. - Ст.7846. - ISSN 1422-0067(eISSN), DOI 10.3390/ijms21217846
Примечания : Cited References:53. - This work was supported by grants from Centre National de la Recherche Scientifique (AAP Prematuration CNRS 2016, to A.B. and N.P.; equipment transfer to S.P. and B.L.), from Agence Nationale de la Recherche (AAP Prematuration FCS/IDEX Paris Saclay, to A.B. and N.P., France BioImaging infrastructure ANR-10-INBS-04, ANR-11-EQPX-029 to N.P.), from Fondation pour la Recherche sur le Cerveau/Rotary Club de France (B.L.), and from RFBR (project number 20-04-00085 to N.P.M. and E.S.V.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Предметные рубрики: IN-VIVO
PHOTOPROTEIN AEQUORIN
CA2+-REGULATED PHOTOPROTEINS
SPREADING
Аннотация: Considerable efforts have been focused on shifting the wavelength of aequorin Ca2+-dependent blue bioluminescence through fusion with fluorescent proteins. This approach has notably yielded the widely used GFP-aequorin (GA) Ca2+ sensor emitting green light, and tdTomato-aequorin (Redquorin), whose bioluminescence is completely shifted to red, but whose Ca2+ sensitivity is low. In the present study, the screening of aequorin mutants generated at twenty-four amino acid positions in and around EF-hand Ca2+-binding domains resulted in the isolation of six aequorin single or double mutants (AequorinXS) in EF2, EF3, and C-terminal tail, which exhibited markedly higher Ca2+ sensitivity than wild-type aequorin in vitro. The corresponding Redquorin mutants all showed higher Ca2+ sensitivity than wild-type Redquorin, and four of them (RedquorinXS) matched the Ca2+ sensitivity of GA in vitro. RedquorinXS mutants exhibited unaltered thermostability and peak emission wavelengths. Upon stable expression in mammalian cell line, all RedquorinXS mutants reported the activation of the P2Y2 receptor by ATP with higher sensitivity and assay robustness than wt-Redquorin, and one, RedquorinXS-Q159T, outperformed GA. Finally, wide-field bioluminescence imaging in mouse neocortical slices showed that RedquorinXS-Q159T and GA similarly reported neuronal network activities elicited by the removal of extracellular Mg2+. Our results indicate that RedquorinXS-Q159T is a red light-emitting Ca2+ sensor suitable for the monitoring of intracellular signaling in a variety of applications in cells and tissues, and is a promising candidate for the transcranial monitoring of brain activities in living mice.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bakayan A., Picaud S., Malikova N. P., Tricoire L., Lambolez B., Vysotski E. S., Peyrieras N.
Заглавие : Redquorinxs mutants with enhanced calcium sensitivity and bioluminescence output efficiently report cellular and neuronal network activities
Место публикации : Int. J. Mol. Sci.: MDPI AG, 2020. - Vol. 21, Is. 21. - Ст.7846. - С. 1-22. - ISSN 16616596 (ISSN), DOI 10.3390/ijms21217846
Аннотация: Considerable efforts have been focused on shifting the wavelength of aequorin Ca2+? dependent blue bioluminescence through fusion with fluorescent proteins. This approach has notably yielded the widely used GFP?aequorin (GA) Ca2+ sensor emitting green light, and tdTomato-aequorin (Redquorin), whose bioluminescence is completely shifted to red, but whose Ca2+ sensitivity is low. In the present study, the screening of aequorin mutants generated at twenty?four amino acid positions in and around EF?hand Ca2+?binding domains resulted in the isolation of six aequorin single or double mutants (AequorinXS) in EF2, EF3, and C?terminal tail, which exhibited markedly higher Ca2+ sensitivity than wild?type aequorin in vitro. The corresponding Redquorin mutants all showed higher Ca2+ sensitivity than wild?type Redquorin, and four of them (RedquorinXS) matched the Ca2+ sensitivity of GA in vitro. RedquorinXS mutants exhibited unaltered thermostability and peak emission wavelengths. Upon stable expression in mammalian cell line, all RedquorinXS mutants reported the activation of the P2Y2 receptor by ATP with higher sensitivity and assay robustness than wt?Redquorin, and one, RedquorinXS?Q159T, outperformed GA. Finally, wide?field bioluminescence imaging in mouse neocortical slices showed that RedquorinXS?Q159T and GA similarly reported neuronal network activities elicited by the removal of extracellular Mg2+. Our results indicate that RedquorinXS?Q159T is a red light?emitting Ca2+ sensor suitable for the monitoring of intracellular signaling in a variety of applications in cells and tissues, and is a promising candidate for the transcranial monitoring of brain activities in living mice. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Eremeeva, Elena, V, Jiang, Tianyu, Malikova, Natalia P., Li, Minyong, Vysotski, Eugene S.
Заглавие : Bioluminescent Properties of Semi-Synthetic Obelin and Aequorin Activated by Coelenterazine Analogues with Modifications of C-2, C-6, and C-8 Substituents
Колич.характеристики :21 с
Коллективы : RFBRRussian Foundation for Basic Research (RFBR); NSFCNational Natural Science Foundation of China (NSFC) [20-54-53011]; Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR) [18-44-242001]; Krasnoyarsk Regional Fund of Science; National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [81874308]; Shandong Natural Science FoundationNatural Science Foundation of Shandong Province [ZR2018ZC0233]; Government of Krasnoyarsk Territory
Место публикации : Int. J. Mol. Sci.: MDPI, 2020. - Vol. 21, Is. 15. - Ст.5446. - ISSN 1422-0067(eISSN), DOI 10.3390/ijms21155446
Примечания : Cited References:50. - The reported study was funded by RFBR and NSFC according to the research project No. 20-54-53011 (E.V.E. and N.P.M.), Russian Foundation for Basic Research (No. 18-44-242001), Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science (E.S.V.), the National Natural Science Foundation of China (No. 81874308), and the Shandong Natural Science Foundation (No. ZR2018ZC0233) (M.L.).
Предметные рубрики: CA2+-REGULATED PHOTOPROTEINS
SPECTROSCOPIC PROPERTIES
Аннотация: Ca2+-regulated photoproteins responsible for bioluminescence of a variety of marine organisms are single-chain globular proteins within the inner cavity of which the oxygenated coelenterazine, 2-hydroperoxycoelenterazine, is tightly bound. Alongside with native coelenterazine, photoproteins can also use its synthetic analogues as substrates to produce flash-type bioluminescence. However, information on the effect of modifications of various groups of coelenterazine and amino acid environment of the protein active site on the bioluminescent properties of the corresponding semi-synthetic photoproteins is fragmentary and often controversial. In this paper, we investigated the specific bioluminescence activity, light emission spectra, stopped-flow kinetics and sensitivity to calcium of the semi-synthetic aequorins and obelins activated by novel coelenterazine analogues and the recently reported coelenterazine derivatives. Several semi-synthetic photoproteins activated by the studied coelenterazine analogues displayed sufficient bioluminescence activities accompanied by various changes in the spectral and kinetic properties as well as in calcium sensitivity. The poor activity of certain semi-synthetic photoproteins might be attributed to instability of some coelenterazine analogues in solution and low efficiency of 2-hydroperoxy adduct formation. In most cases, semi-synthetic obelins and aequorins displayed different properties upon being activated by the same coelenterazine analogue. The results indicated that the OH-group at the C-6 phenyl ring of coelenterazine is important for the photoprotein bioluminescence and that the hydrogen-bond network around the substituent in position 6 of the imidazopyrazinone core could be the reason of different bioluminescence activities of aequorin and obelin with certain coelenterazine analogues.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Eremeeva, Elena V., Vysotski, Eugene S.
Заглавие : Exploring Bioluminescence Function of the Ca2+-regulated Photoproteins with Site-directed Mutagenesis
Колич.характеристики :16 с
Коллективы : Russian Foundation for Basic Research [17-04-00764]; Russian Academy of Sciences [0356-2017-0017]
Место публикации : Photochem. Photobiol.: WILEY, 2019. - Vol. 95, Is. 1. - С. 8-23. - ISSN 0031-8655, DOI 10.1111/php.12945. - ISSN 1751-1097(eISSN)
Примечания : Cited References:88. - This work was supported by grant 17-04-00764 of Russian Foundation for Basic Research and the state budgetallocated to the fundamental research at the Russian Academy of Sciences (project 0356-2017-0017).
Предметные рубрики: CALCIUM-BINDING PHOTOPROTEIN
GREEN-FLUORESCENT PROTEIN
JELLYFISH
Ключевые слова (''Своб.индексиров.''): bioluminescence--coelenterazine--aequorin--obelin--clytin--mitrocomin--ef-hand protein
Аннотация: Site-directed mutagenesis is a powerful tool to investigate the structure-function relationship of proteins and a function of certain amino acid residues in catalytic conversion of substrates during enzymatic reactions. Hence, it is not surprising that this approach was repeatedly applied to elucidate the role of certain amino acid residues in various aspects of photoprotein bioluminescence, mostly for aequorin and obelin, and to design mutant photoproteins with altered properties (modified calcium affinity, faster or slower bioluminescence kinetics, different emission color) which would either allow the development of novel bioluminescent assays or improvement of characteristics of the already existing ones. This information, however, is scattered over different articles. In this review, we systematize the findings that were made using site-directed mutagenesis studies regarding the impact of various amino acid residues on bioluminescence of hydromedusan Ca2+-regulated photoproteins. All key residues that have been identified are pinpointed, and their influence on different aspects of photoprotein functioning such as active photoprotein complex formation, bioluminescence reaction, calcium response and light emitter formation is discussed.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Eremeeva, Elena V., Vysotski, Eugene S.
Заглавие : Bioluminescent and biochemical properties of Cys-free Ca2+-regulated photoproteins obelin and aequorin
Колич.характеристики :9 с
Коллективы : Russian Academy of Sciences [03562016-0712, 0356-2015-0103]; RFBR [17-04-00764]
Место публикации : J. Photochem. Photobiol. B-Biol.: ELSEVIER SCIENCE SA, 2017. - Vol. 174. - С. 97-105. - ISSN 1011-1344, DOI 10.1016/j.jphotobio1.2017.07.021
Примечания : Cited References:54. - This work was supported by the state budget allocated to the fundamental research at the Russian Academy of Sciences (projects 03562016-0712 and 0356-2015-0103) and the RFBR grant 17-04-00764.
Предметные рубрики: SEQUENCE-ANALYSIS
APO-OBELIN
INTRINSIC FLUORESCENCE
COELENTERAZINE
Ключевые слова (''Своб.индексиров.''): bioluminescence--coelenterazine--photoprotein--coelenteramide--cysteine--serine
Аннотация: Bioluminescence of a variety of marine coelenterates is determined by Ca2+-regulated photoproteins. A strong interest in these proteins is for their wide analytical potential as intracellular calcium indicators and labels for in vitro binding assays. The presently known hydromedusan Ca2+-regulated photoproteins contain three (aequorin and clytin) or five (obelin and mitrocomin) cysteine residues with one of them strictly conserved. We have constructed Cys-free aequorin and obelin by substitution of all cysteines to serine residues. Such mutants should be of interest for researchers by the possibility to avoid the incubation with dithiothreitol (or p-mercaptoethanol) required for producing an active photoprotein that is important for some prospective analytical assays in which the photoprotein is genetically fused with a target protein sensitive to the reducing agents. Cys-free mutants were expressed in Escherichia coil, purified, and characterized regarding the efficiency of photoprotein complex formation, functional activity, and conformational stability. The replacement of cysteine residues has been demonstrated to affect different properties of aequorin and obelin. Cys-free aequorin displays a two-fold lower specific bioluminescence activity but preserves similar activation properties and light emission kinetics compared to the wild -type aequorin. In contrast, Cys-free obelin retains only 10% of the bioluminescence activity of wild-type obelin as well as binding coelenterazine and forming active photoprotein much less effectively. In addition, the substitution of Cys residues drastically changes the bioluminescence kinetics of obelin completely eliminating a "fast" component from the light signal decay curve. At the same time, the replacement of Cys residues increases conformational flexibility of both aequorin and obelin molecules, but again, the effect is more prominent in the case of obelin. The values of thermal midpoints of unfolding (Tm) were determined to be 53.3 0.2 and 44.6 0.4 C for aequorin and Cys-free aequorin, and 49.1 0.1 and 28.8 0.3 C for obelin and Cys-free obelin, respectively. Thus, so far only Cys-free aequorin is suitable as a partner for fusing with a tag sensitive to reducing agents since the aequorin mutant preserves almost 50% of the bioluminescent activity and can be produced with a substantial yield.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Eremeeva, Elena V., Bartsev, Sergey I., van Berkel, Willem J. H., Vysotski, Eugene S.
Заглавие : Unanimous Model for Describing the Fast Bioluminescence Kinetics of Ca2+-regulated Photoproteins of Different Organisms
Колич.характеристики :8 с
Коллективы : RFBR [14-04-31092]; Russian Academy of Sciences [01201351504, 01201351502]
Место публикации : Photochem. Photobiol.: WILEY, 2017. - Vol. 93, Is. 2. - С. 495-502. - ISSN 0031-8655, DOI 10.1111/php.12664. - ISSN 1751-1097(eISSN)
Примечания : Cited References:55. - This work was supported by RFBR grant 14-04-31092 and the state budget allocated to the fundamental research at the Russian Academy of Sciences (projects 01201351504 and 01201351502).
Предметные рубрики: GREEN-FLUORESCENT PROTEIN
AEQUORIN BIOLUMINESCENCE
SEQUENCE-ANALYSIS
Аннотация: Upon binding their metal ion cofactors, Ca2+-regulated photoproteins display a rapid increase of light signal, which reaches its peak within milliseconds. In the present study, we investigate bioluminescence kinetics of the entire photoprotein family. All five recombinant hydromedusan Ca2+-regulated photoproteinsaequorin from Aequorea victoria, clytin from Clytia gregaria, mitrocomin from Mitrocoma cellularia and obelins from Obelia longissima and Obelia geniculatademonstrate the same bioluminescent kinetics pattern. Based on these findings, for the first time we propose a unanimous kinetic model describing the bioluminescence mechanism of Ca2+-regulated photoproteins.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrova, Alena S., Lukonina, Anna A., Badun, Gennadii A., Kudryasheva, Nadezhda S.
Заглавие : Fluorescent coelenteramide-containing protein as a color bioindicator for low-dose radiation effects
Колич.характеристики :5 с
Коллективы : Russian Academy of Sciences [01201351504]; Russian Foundation for Basic Research [16-34-00695]
Место публикации : Anal. Bioanal. Chem.: SPRINGER HEIDELBERG, 2017. - Vol. 409, Is. 18. - С. 4377-4381. - ISSN 1618-2642, DOI 10.1007/s00216-017-0404-9. - ISSN 1618-2650(eISSN)
Примечания : Cited References:22. - This work was supported by the state budget allocated to the fundamental research at the Russian Academy of Sciences (project 01201351504) and by the Russian Foundation for Basic Research, Grant No. 16-34-00695.
Предметные рубрики: LUMINOUS MARINE-BACTERIA
DISCHARGED-OBELIN
AEQUORIN
Ключевые слова (''Своб.индексиров.''): fluorescent protein--coelenteramide--discharged photoprotein obelin--multicolor bioindicator--radiotoxicity
Аннотация: The study addresses the application of fluorescent coelenteramide-containing proteins as color bioindicators for radiotoxicity evaluation. Biological effects of chronic low-dose radiation are under investigation. Tritiated water (200 MBq/L) was used as a model source of low-intensive ionizing radiation of beta type. 'Discharged obelin,' product of bioluminescent reaction of marine coelenterate Obelia longissimi, was used as a representative of the coelenteramide-containing proteins. Coelenteramide, fluorophore of discharged obelin, is a photochemically active molecule; it produces fluorescence forms of different color. Contributions of 'violet' and 'blue-green' forms to the visible fluorescence serve as tested parameters. The contributions depend on the coelenteramide's microenvironment in the protein, and, hence, evaluate distractive ability and toxicity of radiation. The protein samples were exposed to beta radiation for 18 days, and maximal dose accumulated by the samples was 0.28 Gy, being close to a tentative limit of a low-dose interval. Increase of relative contribution of 'violet' fluorescence under exposure to the beta irradiation was revealed. High sensitivity of the protein-based test system to low-dose ionizing radiation (to 0.03 Gy) was demonstrated. The study develops physicochemical understanding of radiotoxic effects.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Eremeeva E. V., Vysotski E. S.
Заглавие : Bioluminescent and biochemical properties of Cys-free Ca2+-regulated photoproteins obelin and aequorin
Место публикации : J. Photochem. Photobiol. B Biol.: Elsevier B.V., 2017. - Vol. 174. - С. 97-105. - ISSN 10111344 (ISSN) , DOI 10.1016/j.jphotobiol.2017.07.021
Ключевые слова (''Своб.индексиров.''): bioluminescence--coelenteramide--coelenterazine--cysteine--photoprotein--serine
Аннотация: Bioluminescence of a variety of marine coelenterates is determined by Ca2+-regulated photoproteins. A strong interest in these proteins is for their wide analytical potential as intracellular calcium indicators and labels for in vitro binding assays. The presently known hydromedusan Ca2+-regulated photoproteins contain three (aequorin and clytin) or five (obelin and mitrocomin) cysteine residues with one of them strictly conserved. We have constructed Cys-free aequorin and obelin by substitution of all cysteines to serine residues. Such mutants should be of interest for researchers by the possibility to avoid the incubation with dithiothreitol (or ?-mercaptoethanol) required for producing an active photoprotein that is important for some prospective analytical assays in which the photoprotein is genetically fused with a target protein sensitive to the reducing agents. Cys-free mutants were expressed in Escherichia coli, purified, and characterized regarding the efficiency of photoprotein complex formation, functional activity, and conformational stability. The replacement of cysteine residues has been demonstrated to affect different properties of aequorin and obelin. Cys-free aequorin displays a two-fold lower specific bioluminescence activity but preserves similar activation properties and light emission kinetics compared to the wild-type aequorin. In contrast, Cys-free obelin retains only ~ 10% of the bioluminescence activity of wild-type obelin as well as binding coelenterazine and forming active photoprotein much less effectively. In addition, the substitution of Cys residues drastically changes the bioluminescence kinetics of obelin completely eliminating a “fast” component from the light signal decay curve. At the same time, the replacement of Cys residues increases conformational flexibility of both aequorin and obelin molecules, but again, the effect is more prominent in the case of obelin. The values of thermal midpoints of unfolding (Tm) were determined to be 53.3 ± 0.2 and 44.6 ± 0.4 °C for aequorin and Cys-free aequorin, and 49.1 ± 0.1 and 28.8 ± 0.3 °C for obelin and Cys-free obelin, respectively. Thus, so far only Cys-free aequorin is suitable as a partner for fusing with a tag sensitive to reducing agents since the aequorin mutant preserves almost 50% of the bioluminescent activity and can be produced with a substantial yield. © 2017 Elsevier B.V.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Alieva R. R., Tomilin F. N., Kuzubov A. A., Ovchinnikov S. G., Kudryasheva N. S.
Заглавие : Ultraviolet fluorescence of coelenteramide and coelenteramide-containing fluorescent proteins. Experimental and theoretical study
Место публикации : J. Photochem. Photobiol. B Biol. - 2016. - Vol. 162. - С. 318-323. - ISSN 10111344 (ISSN) , DOI 10.1016/j.jphotobiol.2016.07.004
Ключевые слова (''Своб.индексиров.''): aequorin--b3lyp--coelenteramide--discharged photoproteins--excitation energy--fluorescence--fluorescent protein--obelin
Аннотация: Coelenteramide-containing fluorescent proteins are products of bioluminescent reactions of marine coelenterates. They are called ‘discharged photoproteins’. Their light-induced fluorescence spectra are variable, depending considerably on external conditions. Current work studies a dependence of light-induced fluorescence spectra of discharged photoproteins obelin, aequorin, and clytin on excitation energy. It was demonstrated that photoexcitation to the upper electron-excited states (260–300 nm) of the discharged photoproteins initiates a fluorescence peak in the near UV region, in addition to the blue-green emission. To characterize the UV fluorescence, the light-induced fluorescence spectra of coelenteramide (CLM), fluorophore of the discharged photoproteins, were studied in methanol solution. Similar to photoproteins, the CLM spectra depended on photoexcitation energy; the additional peak (330 nm) in the near UV region was observed in CLM fluorescence at higher excitation energy (260–300 nm). Quantum chemical calculations by time depending method with B3LYP/cc-pVDZ showed that the conjugated pyrazine-phenolic fragment and benzene moiety of CLM molecule are responsible for the additional UV fluorescence peak. Quantum yields of CLM fluorescence in methanol were 0.028 ± 0.005 at 270–340 nm photoexcitation. A conclusion was made that the UV emission of CLM might contribute to the UV fluorescence of the discharged photoproteins. The study develops knowledge on internal energy transfer in biological structures – complexes of proteins with low-weight aromatic molecules. © 2016 Elsevier B.V.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Burakova L. P., Natashin P. V., Markova S. V., Eremeeva E. V., Malikova N. P., Cheng C., Liu Z. -J., Vysotski E. S.
Заглавие : Mitrocomin from the jellyfish Mitrocoma cellularia with deleted C-terminal tyrosine reveals a higher bioluminescence activity compared to wild type photoprotein
Место публикации : J. Photochem. Photobiol. B Biol. - 2016. - Vol. 162. - С. 286-297. - ISSN 10111344 (ISSN) , DOI 10.1016/j.jphotobiol.2016.06.054
Аннотация: The full-length cDNA genes encoding five new isoforms of Ca2 +-regulated photoprotein mitrocomin from a small tissue sample of the outer bell margin containing photocytes of only one specimen of the luminous jellyfish Mitrocoma cellularia were cloned, sequenced, and characterized after their expression in Escherichia coli and subsequent purification. The analysis of cDNA nucleotide sequences encoding mitrocomin isoforms allowed suggestion that two isoforms might be the products of two allelic genes differing in one amino acid residue (64R/Q) whereas other isotypes appear as a result of transcriptional mutations. In addition, the crystal structure of mitrocomin was determined at 1.30 A resolution which expectedly revealed a high similarity with the structures of other hydromedusan photoproteins. Although mitrocomin isoforms reveal a high degree of identity of amino acid sequences, they vary in specific bioluminescence activities. At that, all isotypes displayed the identical bioluminescence spectra (473–474 nm with no shoulder at 400 nm). Fluorescence spectra of Ca2 +-discharged mitrocomins were almost identical to their light emission spectra similar to the case of Ca2 +-discharged aequorin, but different from Ca2 +-discharged obelins and clytin which fluorescence is red-shifted by 25–30 nm from bioluminescence spectra. The main distinction of mitrocomin from other hydromedusan photoproteins is an additional Tyr at the C-terminus. Using site-directed mutagenesis, we showed that this Tyr is not important for bioluminescence because its deletion even increases specific activity and efficiency of apo-mitrocomin conversion into active photoprotein, in contrast to C-terminal Pro of other photoproteins. Since genes in a population generally exist as different isoforms, it makes us anticipate the cloning of even more isoforms of mitrocomin and other hydromedusan photoproteins with different bioluminescence properties. © 2016 Elsevier B.V.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Burakova L. P., Stepanyuk G. A., Eremeeva E. V., Vysotski E. S.
Заглавие : Role of certain amino acid residues of the coelenterazine-binding cavity in bioluminescence of light-sensitive Ca2+-regulated photoprotein berovin
Место публикации : Photochem. Photobiol. Sci. - 2016. - Vol. 15, Is. 5. - С. 691-704. - ISSN 1474905X (ISSN) , DOI 10.1039/c6pp00050a
Аннотация: Bright bioluminescence of ctenophores is caused by Ca2+-regulated photoproteins. Although these photoproteins are functionally identical to and share many properties of cnidarian photoproteins, like aequorin and obelin, and retain the same spatial architecture, they are extremely sensitive to light, i.e. lose the ability to bioluminesce on exposure to light over the entire absorption spectrum. In addition, the degree of identity of their amino acid sequences with those of cnidarian photoproteins is only 29.4%. This suggests that the residues involved in bioluminescence of ctenophore and cnidarian photoproteins significantly differ. Here we describe the bioluminescent properties of berovin mutants with substitution of the residues located in the photoprotein internal cavity. Since the spatial structure of berovin bound with a substrate is not determined yet, to identify these residues we have modeled it with an accommodated substrate using the structures of some cnidarian Ca2+-regulated photoproteins with bound coelenterazine or coelenteramide as templates in order to obtain an adequate sampling and to take into account all possible conformers and variants for ligand-protein docking. Based on the impact of substitutions on the bioluminescent properties and model structures we speculate that within the internal cavity of ctenophore photoproteins, coelenterazine is bound as a 2-peroxy anion adduct which is stabilized owing to Coulomb interaction with a positively charged guanidinium group of Arg41 paired with Tyr204. In this case, the bioluminescence reaction is triggered by only calcium-induced conformational changes leading to the disturbance of charge-charge interaction. © 2016 The Royal Society of Chemistry and Owner Societies.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Burakova L. P., Natashin P. V., Malikova N. P., Niu F., Pu M., Vysotski E. S., Liu Z.-J.
Заглавие : All Ca2+-binding loops of light-sensitive ctenophore photoprotein berovin bind magnesium ions: The spatial structure of Mg2 +-loaded apo-berovin
Место публикации : J. Photochem. Photobiol. B Biol. - 2016. - Vol. 154. - С. 57-66. - ISSN 10111344 (ISSN) , DOI 10.1016/j.jphotobiol.2015.11.012
Ключевые слова (''Своб.индексиров.''): aequorin--bioluminescence--calcium--coelenterazine--obelin
Аннотация: Light-sensitive photoprotein berovin accounts for a bright bioluminescence of ctenophore Beroe abyssicola. Berovin is functionally identical to the well-studied Ca2+-regulated photoproteins of jellyfish, however in contrast to those it is extremely sensitive to the visible light. Berovin contains three EF-hand Ca2+-binding sites and consequently belongs to a large family of the EF-hand Ca2+-binding proteins. Here we report the spatial structure of apo-berovin with bound Mg2+ determined at 1.75 A. The magnesium ion is found in each functional EF-hand loop of a photoprotein and coordinated by oxygen atoms donated by the side-chain groups of aspartate, carbonyl groups of the peptide backbone, or hydroxyl group of serine with characteristic oxygen-Mg2+ distances. As oxygen supplied by the side-chain of the twelfth residue of all Ca2+-binding loops participates in the magnesium ion coordination, it was suggested that Ca2+-binding loops of berovin belong to the mixed Ca2+/Mg2+ rather than Ca2+-specific type. In addition, we report an effect of physiological concentration of Mg2+ on bioluminescence of berovin (sensitivity to Ca2+, rapid-mixed kinetics, light-sensitivity, thermostability, and apo-berovin conversion into active protein). The different impact of physiological concentration of Mg2+ on berovin bioluminescence as compared to hydromedusan photoproteins was attributed to different affinities of the Ca2 +-binding sites of these photoproteins to Mg2+. © 2015 Elsevier B.V. All rights reserved.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Eremeeva, Elena V., van Berkel, Willem J. H., Vysotski, Eugene S.
Заглавие : Transient-state kinetic analysis of complex formation between photoprotein clytin and GFP from jellyfish Clytia gregaria
Колич.характеристики :10 с
Коллективы : Russian Science Foundation [14-14-01119]
Место публикации : FEBS Lett.: WILEY-BLACKWELL, 2016. - Vol. 590, Is. 3. - С. 307-316. - ISSN 0014-5793, DOI 10.1002/1873-3468.12052. - ISSN 1873-3468(eISSN)
Примечания : Cited References:34. - This study was supported by the grant 14-14-01119 of the Russian Science Foundation.
Предметные рубрики: GREEN-FLUORESCENT PROTEIN
ENERGY-TRANSFER
CA2+-REGULATED
Ключевые слова (''Своб.индексиров.''): aequorin--bioluminescence--coelenterazine--fret--obelin--protein-protein--interaction
Аннотация: Luminous organisms use different protein-mediated strategies to modulate light emission color. Here, we report the transient-state kinetic studies of the interaction between photoprotein clytin from Clytia gregaria and its antenna protein, cgreGFP. We propose that cgreGFP forms a transient complex with Ca2+-bound clytin before the excited singlet state of the coelenteramide product is formed. From the spectral distribution and donor-acceptor separation distance, we infer that clytin reaction intermediates may interact only with the middle side part of cgreGFP.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Malikova N. P., Borgdorff A. J., Vysotski E. S.
Заглавие : Semisynthetic photoprotein reporters for tracking fast Ca2+ transients
Место публикации : Photochem. Photobiol. Sci. - 2015. - Vol. 14, Is. 12. - С. 2213-2224. - ISSN 1474905X (ISSN) , DOI 10.1039/c5pp00328h
Аннотация: Changes in the intracellular concentration of free ionized calcium ([Ca2+]i) control a host of cellular processes as varied as vision, muscle contraction, neuronal signal transmission, proliferation, apoptosis etc. The disturbance in Ca2+-signaling causes many severe diseases. To understand the mechanisms underlying the control by calcium and how disorder of this regulation relates to pathological conditions, it is necessary to measure [Ca2+]i. The Ca2+-regulated photoproteins which are responsible for bioluminescence of marine coelenterates have been successfully used for this purpose over the years. Here we report the results on comparative characterization of bioluminescence properties of aequorin from Aequorea Victoria, obelin from Obelia longissima, and clytin from Clytia gregaria charged by native coelenterazine and coelenterazine analogues f, i, and hcp. The comparison of specific bioluminescence activity, stability, emission spectra, stopped-flow kinetics, sensitivity to calcium, and effect of physiological concentrations of Mg2+ establishes obelin-hcp as an excellent semisynthetic photoprotein to keep track of fast intracellular Ca2+ transients. The rate of rise of its light signal on a sudden change of [Ca2+] is almost 3- and 11-fold higher than those of obelin and aequorin with native coelenterazine, respectively, and 20 times higher than that of the corresponding aequorin-hcp. In addition, obelin-hcp preserves a high specific bioluminescence activity and displays higher Ca2+-sensitivity as compared to obelin charged by native coelenterazine and sensitivity to Ca2+ comparable with those of aequorin-f and aequorin-hcp. © The Royal Society of Chemistry and Owner Societies 2015.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gealageas R..., Malikova N.P., Picaud S..., Borgdorff A.J., Burakova L.P., Brulet P..., Vysotski E.S., Dodd R.H.
Заглавие : Bioluminescent properties of obelin and aequorin with novel coelenterazine analogues
Колич.характеристики :13 с
Коллективы : ICSN; CNRS Physics, Chemistry and Biology interface grant; RFBR [12-04-00131]; Government of Russian Federation [11.G34.31.0058]; ANR
Место публикации : Anal. Bioanal. Chem.: SPRINGER HEIDELBERG, 2014. - Vol. 406, Is. 11. - С. 2695-2707. - ISSN 1618-2642, DOI 10.1007/s00216-014-7656-4. - ISSN 1618-2650
Примечания : Cited References: 57. - R.G. acknowledges the ICSN for a fellowship. We are grateful for the ANR grant to P.B. and a CNRS Physics, Chemistry and Biology interface grant to R.H.D. and P.B.; N.P.M, L.P.B., and E.S.V. acknowledge the RFBR grant 12-04-00131 and the Program of the Government of Russian Federation "Measures to attract leading scientists to Russian educational institutions" (grant 11.G34.31.0058). P.B. and A.J.B. are indebted to Eric Karplus from Science Wares Inc. for helping with single-photon imaging software.
Предметные рубрики: PHOTOPROTEIN OBELIN
CRYSTAL-STRUCTURE
CA2+-REGULATED PHOTOPROTEINS
CA2+-ACTIVATED PHOTOPROTEIN
SEMISYNTHETIC AEQUORINS
ANGSTROM RESOLUTION
RECOMBINANT OBELIN
BINDING PROTEIN
CALCIUM-BINDING
CA2+ DYNAMICS
Ключевые слова (''Своб.индексиров.''): bioluminescence--luciferase--photoprotein--coelenterazine
Аннотация: The main analytical use of Ca2+-regulated photoproteins from luminous coelenterates is for real-time non-invasive visualization of intracellular calcium concentration ([Ca2+](i)) dynamics in cells and whole organisms. A limitation of this approach for in vivo deep tissue imaging is the fact that blue light emitted by the photoprotein is highly absorbed by tissue. Seven novel coelenterazine analogues were synthesized and their effects on the bioluminescent properties of recombinant obelin from Obelia longissima and aequorin from Aequorea victoria were evaluated. Only analogues having electron-donating groups (m-OCH3 and m-OH) on the C6 phenol moiety or an extended resonance system at the C8 position (1-naphthyl and alpha-styryl analogues) showed a significant red shift of light emission. Of these, only the alpha-styryl analogue displayed a sufficiently high light intensity to allow eventual tissue penetration. The possible suitability of this compound for in vivo assays was corroborated by studies with aequorin which allowed the monitoring of [Ca2+](i) dynamics in cultured CHO cells and in hippocampal brain slices. Thus, the alpha-styryl coelenterazine analogue might be potentially useful for non-invasive, in vivo bioluminescence imaging in deep tissues of small animals.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Eremeeva E.V., Burakova L.P., Krasitskaya V.V., Kudryavtsev A.N., Shimomura O..., Frank L.A.
Заглавие : Hydrogen-bond networks between the C-terminus and Arg from the first alpha-helix stabilize photoprotein molecules
Колич.характеристики :7 с
Коллективы : RFBR [12-04-00753-a]; Government of Russian Federation [11.G34.31.0058]
Место публикации : Photochem. Photobiol. Sci.: ROYAL SOC CHEMISTRY, 2014. - Vol. 13, Is. 3. - С. 541-547. - ISSN 1474-905X, DOI 10.1039/c3pp50369k. - ISSN 1474-9092
Примечания : Cited References: 22. - The work was supported by RFBR grant 12-04-00753-a, by the Program of the Government of Russian Federation "Measures to Attract Leading Scientists to Russian Educational Institutions" (grant 11.G34.31.0058).
Предметные рубрики: GREEN FLUORESCENT PROTEIN
CA2+-REGULATED PHOTOPROTEIN
BIOLUMINESCENT IMMUNOASSAY
COELENTERAZINE BINDING
ANGSTROM RESOLUTION
ENERGY-TRANSFER
FUSION PROTEIN
APO-OBELIN
AEQUORIN
EXPRESSION
Аннотация: Previous studies have stated that aequorin loses most of its bioluminescence activity upon modification of the C-terminus, thus limiting the production of photoprotein fusion proteins at its N-terminus. In the present work, we investigate the importance of the C-terminal proline and the hydrogen bonds it forms for photoprotein active complex formation, stability and functional activity. According to the crystal structures of obelin and aequorin, two Ca2+-regulated photoproteins, the carboxyl group of the C-terminal Pro forms two hydrogen bonds with the side chain of Arg21 (Arg15 in aequorin case) situated in the first a-helix. Whereas, deletion or substitution of the C-terminal proline could noticeably change the bioluminescence activity, stability or the yield of an active photoprotein complex. Therefore, modifications of the first alpha-helix Arg has a clear destructive effect on the main photoprotein properties. A C-terminal hydrogen-bond network is proposed to be important for the stability of photoprotein molecules towards external disturbances, when taking part in the formation of locked protein conformations and isolation of coelenterazine-binding cavities.
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