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da Cunha AR, Duarte EL, Vignoli Muniz GS, Coutinho K, Lamy MT. New insights into the interaction of emodin with lipid membranes. Biophys Chem 2024; 309:107233. [PMID: 38579435 DOI: 10.1016/j.bpc.2024.107233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/26/2024] [Accepted: 04/01/2024] [Indexed: 04/07/2024]
Abstract
Emodin is a natural anthraquinone derivative found in nature, widely known as an herbal medicine. Here, the partition, location, and interaction of emodin with lipid membranes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) are experimentally investigated with different techniques. Our studies have considered the neutral form of emodin (EMH) and its anionic/deprotonated form (EM-), and their interaction with a more and less packed lipid membrane, DMPC at the gel and fluid phases, respectively. Though DSC results indicate that the two species, EMH and EM-, similarly disrupt the packing of DMPC bilayers, spin labels clearly show that EMH causes a stronger bilayer disruption, both in gel and fluid DMPC. Fluorescence spectroscopy shows that both EMH and EM- have a high affinity for DMPC: the binding of EM- to both gel and fluid DMPC bilayers was found to be quite similar, and similar to that of EMH to gel DMPC, Kp = (1.4 ± 0.3)x103. However, EMH was found to bind twice more strongly to fluid DMPC bilayers, Kp = (3.2 ± 0.3)x103. Spin labels and optical absorption spectroscopy indicate that emodin is located close to the lipid bilayer surface, and suggest that EM- is closer to the lipid/water interface than EMH, as expected. The present studies present a relevant contribution to the current understanding of the effect the two species of emodin, EMH and EM-, present on different microregions of an organism, as local pH values can vary significantly, can cause in a neutral lipid membrane, either more or less packed, liked gel and fluid DMPC, respectively, and could be extended to lipid domains of biological membranes.
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Affiliation(s)
- Antonio R da Cunha
- Universidade Federal do Maranhão, UFMA, Campus Balsas, 65800-000, Maranhão, Brazil; Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil.
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil
| | - Gabriel S Vignoli Muniz
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil; Instituto de Química, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília 70910-900, Brazil
| | - Kaline Coutinho
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil
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Sato R, Utagawa A, Fushimi K, Li F, Isono T, Tajima K, Satoh T, Sato SI, Hirata H, Kikkawa Y, Yamamoto T. Molecular Weight-Dependent Oxidation and Optoelectronic Properties of Defect-Free Macrocyclic Poly(3-hexylthiophene). Polymers (Basel) 2023; 15:polym15030666. [PMID: 36771966 PMCID: PMC9920727 DOI: 10.3390/polym15030666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
The redox behaviors of macrocyclic molecules with an entirely π-conjugated system are of interest due to their unique optical, electronic, and magnetic properties. In this study, defect-free cyclic P3HT with a degree of polymerization (DPn) from 14 to 43 was synthesized based on our previously established method, and its unique redox behaviors arising from the cyclic topology were investigated. Cyclic voltammetry (CV) showed that the HOMO level of cyclic P3HT decreases from -4.86 eV (14 mer) to -4.89 eV (43 mer), in contrast to the linear counterparts increasing from -4.94 eV (14 mer) to -4.91 eV (43 mer). During the CV measurement, linear P3HT suffered from electro-oxidation at the chain ends, while cyclic P3HT was stable. ESR and UV-Vis-NIR spectroscopy suggested that cyclic P3HT has stronger dicationic properties due to the interactions between the polarons. On the other hand, linear P3HT showed characteristics of polaron pairs with multiple isolated polarons. Moreover, the dicationic properties of cyclic P3HT were more pronounced for the smaller macrocycles.
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Affiliation(s)
- Ryohei Sato
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Atsuo Utagawa
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Koji Fushimi
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Feng Li
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Takuya Isono
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Kenji Tajima
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Toshifumi Satoh
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Shin-ichiro Sato
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan
| | - Yoshihiro Kikkawa
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan
| | - Takuya Yamamoto
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
- Correspondence:
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Hrabia O, Ditrych M, Ciosek A, Fulara K, Andersen ML, Poreda A. Effect of dry hopping on the oxidative stability of beer. Food Chem 2022; 394:133480. [PMID: 35717916 DOI: 10.1016/j.foodchem.2022.133480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 05/23/2022] [Accepted: 06/12/2022] [Indexed: 11/04/2022]
Abstract
Electron spin resonance (ESR) spectroscopy was used todeterminethe effect of dry hopping on the oxidative stability and antioxidative potential of beer.Commercial beerwasdry-hopped at 5 °C and 20 °Cwith six hop varieties (Polish and American). The rate of radical formation and lag time were found to depend on the variety of hop used. An increase in the lag time and a decrease in the rate of radical formation occurred when dry-hopping was performed at 20 °C for all hop varieties (at 5 °C in some varieties). The lag time had a strong correlation with the TPC (total polyphenols content) in beer. The rate of radical formation was correlated with the iron content of the beer. A decrease in iron concentration was observed after dry-hopping at 20 °C. Overall, the evaluation of free radical formation using ESR is useful for predicting oxidative changes in beer during storage.
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Affiliation(s)
- Olga Hrabia
- Department of Fermentation Technology and Microbiology, Faculty of Food Technology, University of Agriculture in Krakow, Balicka 122, 30-149 Krakow, Poland.
| | - Maciej Ditrych
- Department of Microbial and Molecular Systems (M(2)S) Laboratory of Enzyme, Fermentation and Brewing Technology (EFBT), Technology Campus Ghent, KU Leuven, Gebroeders De Smetstraat 1, B-9000 Ghent, Belgium; Department of Food Science, University of Copenhagen, Rolighedsvej 26, DK-1958 Frederiksberg, Denmark
| | - Aneta Ciosek
- Department of Fermentation Technology and Microbiology, Faculty of Food Technology, University of Agriculture in Krakow, Balicka 122, 30-149 Krakow, Poland
| | - Katarzyna Fulara
- Department of Fermentation Technology and Microbiology, Faculty of Food Technology, University of Agriculture in Krakow, Balicka 122, 30-149 Krakow, Poland
| | - Mogens Larsen Andersen
- Department of Food Science, University of Copenhagen, Rolighedsvej 26, DK-1958 Frederiksberg, Denmark
| | - Aleksander Poreda
- Department of Fermentation Technology and Microbiology, Faculty of Food Technology, University of Agriculture in Krakow, Balicka 122, 30-149 Krakow, Poland
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Martynov IV, Inasaridze LN, Troshin PA. Resist or Oxidize: Identifying Molecular Structure-Photostability Relationships for Conjugated Polymers Used in Organic Solar Cells. ChemSusChem 2022; 15:e202101336. [PMID: 34519424 DOI: 10.1002/cssc.202101336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/14/2021] [Indexed: 06/13/2023]
Abstract
Although organic solar cells have started to demonstrate competitive power conversion efficiencies of >18 %, their operational lifetimes remain insufficient for wide practical use and the factors influencing the photostability of absorber materials and completed devices are still not completely understood. A systematic study of two series of structurally similar [XTBT]n and [XTTBTBTT]n polymers (16 structures in total) reveals the building blocks that enable the highest material stability towards photooxidation: fluorene, silafluorene, carbazole, diketopyrrolopyrrole, and isoindigo. Furthermore, a direct correlation is evident between the electronic properties of the conjugated polymers and their reactivity towards oxygen. The structures with the lowest highest occupied molecular orbital (HOMO) energies show the highest electrochemical oxidation potentials and appear to be the most resistant towards chemical oxidation. These relationships set important guidelines for the further rational design of new absorber materials for efficient and stable organic photovoltaics.
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Affiliation(s)
- Ilya V Martynov
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, Academician Semenov avenue 1, Chernogolovka, Moscow Region, 142432, Russian Federation
| | - Liana N Inasaridze
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, Academician Semenov avenue 1, Chernogolovka, Moscow Region, 142432, Russian Federation
| | - Pavel A Troshin
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, Academician Semenov avenue 1, Chernogolovka, Moscow Region, 142432, Russian Federation
- Silesian University of Technology, Akademicka 2A, 44-100, Gliwice, Poland
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Ivoilova A, Mikhalchenko LV, Tsmokalyuk A, Leonova M, Lalov A, Mozharovskaia P, Kozitsina AN, Ivanova AV, Rusinov VL. Redox Conversions of 5-Methyl-6-nitro-7-oxo-4,7-dihydro-1,2,4triazolo[1,5-a]pyrimidinide L-Arginine Monohydrate as a Promising Antiviral Drug. Molecules 2021; 26:5087. [PMID: 34443674 PMCID: PMC8400642 DOI: 10.3390/molecules26165087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 11/25/2022] Open
Abstract
This article presents the results of a study of electrochemical transformations in aqueous and aprotic media of 5-methyl-6-nitro-7-oxo-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidinide l-arginine monohydrate (1a, Triazid) obtained by electrochemical methods and ESR spectroscopy. The effect of pH on the current and the reduction potential of 1a in an aqueous Britton-Robinson buffer solution was studied. It was found that 1a is irreversibly reduced in aqueous acidic media on a glassy carbon electrode in one stage with the participation of six electrons and the formation of 5-methyl-6-amino-7-oxo-1,2,4-triazolo[1,5-a]pyrimidin. The electroreduction of 1a in DMF on a background of tetrabutylammonium salts proceeds in two stages, controlled by the kinetics of second-order reactions. In the first stage, the reduction of 1a is accompanied by protonation by the initial compound of the basic intermediate products formed in the electrode reaction (self-protonation mechanism). The second quasi-reversible stage of the electroreduction 1a corresponds to the formation of a dianion radical upon the reduction of the heterocyclic anion 5-methyl-6-nitro-7-oxo-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidin, which is formed upon the potentials of the first peak. The ESR spectrum of the radical dianion was recorded upon electroreduction of Triazid in the presence of Bu4NOH. The effect of the formation of ion pairs on the reversibility of the second peak of the 1a transformation is shown. A change in the rate and regioselectivity of the protonation of the dianion radical in the presence of Na+ and Li+ ions is assumed. The results of studying the electroreduction of 1a by ESR spectroscopy with a TEMPO trap make it possible to assume the simultaneous formation of both a nitroxyl radical and a radical with the spin density localized on the nitrogen at the 4 position of the six-membered ring.
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Affiliation(s)
- Alexandra Ivoilova
- Institute of Chemical Technology, Ural Federal University, 19, Mira St, 620002 Ekaterinburg, Russia; (A.I.); (A.T.); (P.M.); (A.N.K.); (A.V.I.)
| | - Ludmila V. Mikhalchenko
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47, Leninsky Prospect, 119991 Moscow, Russia; (L.V.M.); (M.L.); (A.L.)
| | - Anton Tsmokalyuk
- Institute of Chemical Technology, Ural Federal University, 19, Mira St, 620002 Ekaterinburg, Russia; (A.I.); (A.T.); (P.M.); (A.N.K.); (A.V.I.)
| | - Marina Leonova
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47, Leninsky Prospect, 119991 Moscow, Russia; (L.V.M.); (M.L.); (A.L.)
| | - Andrey Lalov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47, Leninsky Prospect, 119991 Moscow, Russia; (L.V.M.); (M.L.); (A.L.)
| | - Polina Mozharovskaia
- Institute of Chemical Technology, Ural Federal University, 19, Mira St, 620002 Ekaterinburg, Russia; (A.I.); (A.T.); (P.M.); (A.N.K.); (A.V.I.)
| | - Alisa N. Kozitsina
- Institute of Chemical Technology, Ural Federal University, 19, Mira St, 620002 Ekaterinburg, Russia; (A.I.); (A.T.); (P.M.); (A.N.K.); (A.V.I.)
| | - Alla V. Ivanova
- Institute of Chemical Technology, Ural Federal University, 19, Mira St, 620002 Ekaterinburg, Russia; (A.I.); (A.T.); (P.M.); (A.N.K.); (A.V.I.)
| | - Vladimir L. Rusinov
- Institute of Chemical Technology, Ural Federal University, 19, Mira St, 620002 Ekaterinburg, Russia; (A.I.); (A.T.); (P.M.); (A.N.K.); (A.V.I.)
- Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences, 22 Sofia Kovalevsky St, 620137 Ekaterinburg, Russia
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Jain M, Vashishtha P, Gupta G, Sinha AK, Gupta M, Vij A, Thakur A. Mechanistic insights into defect generation and tuning of optical properties in Zn 1-xFe xAl 2O 4(0.01 ≤ x ≤ 0.40) nanocrystals. Acta Crystallogr B Struct Sci Cryst Eng Mater 2020; 76:757-768. [PMID: 33017309 DOI: 10.1107/s2052520620009130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/04/2020] [Indexed: 06/11/2023]
Abstract
The correlation of several defects and optical and magnetic properties with Fe content in Zn1-xFexAl2O4 (0.01 ≤ x ≤ 0.40) nanocrystals has been scrutinized through X-ray diffraction, O K-edge X-ray absorption near-edge structure, FT-IR, diffuse reflectance, photoluminescence and electron spin-resonance spectroscopies, and vibrating sample magnetometry. Increasing Fe content causes elongation in the octahedral units of the lattice, accompanied by distortion in the octahedral coordination. Fe introduces non-radiative centres in the forbidden gap, thereby tuning the band gap from 4.37 to 3.88 eV and eliminating emission in the visible region. Zn vacancies are found to tail off, while {\rm Fe}_i^{\bullet \bullet \bullet}, {\rm Al}_{\rm Zn}^\bullet and FeAl× antisite defects increase in concentration with increasing Fe content. Inhomogeneous broadening of spin-resonance signals infers strong spin-lattice interactions of Fe3+ ions at distorted octahedral and non-symmetric tetrahedral sites. A transition is observed from paramagnetism to superparamagnetism at higher Fe concentrations. A visual colour change from pearly white to orange-brown is observed in Zn1-xFexAl2O4 nanocrystals with increasing Fe content, revealing its potential candidature for pigments in the paint and dye industries.
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Affiliation(s)
- Megha Jain
- Advanced Materials Research Laboratory, Department of Basic and Applied Sciences, Punjabi University, Patiala, Punjab 147002, India
| | - Pargam Vashishtha
- Advanced Materials and Devices Division, CSIR-National Physical Laboratory, New Delhi 110012, India
| | - Govind Gupta
- Advanced Materials and Devices Division, CSIR-National Physical Laboratory, New Delhi 110012, India
| | - Anil Kumar Sinha
- Raja Ramanna Centre for Advanced Technology, PO CAT, Indore, Madhya Pradesh 452013, India
| | - Mukul Gupta
- UGC-DAE Consortium, Indore Centre, Khandwa Road, Indore, Madhya Pradesh 452017, India
| | - Ankush Vij
- Nanophosphors Laboratory, Department of Physics, Amity University Haryana, Gurgaon, Haryana 122413, India
| | - Anup Thakur
- Advanced Materials Research Laboratory, Department of Basic and Applied Sciences, Punjabi University, Patiala, Punjab 147002, India
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Abbas K, Babić N, Peyrot F. Detection of Superoxide Radical in Adherent Living Cells by Electron Paramagnetic Resonance (EPR) Spectroscopy Using Cyclic Nitrones. Methods Mol Biol 2021; 2202:149-63. [PMID: 32857354 DOI: 10.1007/978-1-0716-0896-8_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2023]
Abstract
Spin trapping with cyclic nitrones coupled to electron paramagnetic resonance (EPR) enables the detection and characterization of oxygen-derived free radicals, such as superoxide and hydroxyl radicals, in living cells. Detection is usually performed on cell suspensions introduced in glass capillaries, gas-permeable tubing, or flat cells, even when cells normally require attachment for growth. However, radical production may be influenced by cell adhesion, while enzymatic or mechanical cell harvesting may damage the cells and alter their metabolic rates. Here, we describe the detection on adherent cells attached to microscope coverslip glasses. This method preserves cell integrity, ensures near physiological conditions for naturally adherent cells, and is relatively simple to set up. Up to 12 conditions can be screened in half a day using a single batch of culture cells.
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Alghazeer R, Burwaiss AA, Howell NK, Alansari WS, Shamlan G, Eskandrani AA. Determining the Cytotoxicity of Oxidized Lipids in Cultured Caco-2 Cells Using Bioimaging Techniques. Molecules 2020; 25:molecules25071693. [PMID: 32272768 PMCID: PMC7180719 DOI: 10.3390/molecules25071693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/01/2020] [Accepted: 04/04/2020] [Indexed: 12/02/2022] Open
Abstract
Fish lipids are comprised of considerable quantities of polyunsaturated acids and are prone to oxidation, producing reactive oxygen species and hydroperoxides. This study aimed to evaluate the biochemical and structural alterations in Caco-2 cells following exposure to 100 μg/mL methyl linoleate or fish oil, and then radiated for 24, 48 or 72 h. Electron spin resonance spectroscopy detected free radicals in the lipid membrane, Raman microscopy observed biochemical alterations and atomic force microscopy identified changes in morphology, such as the breakdown of DNA bonds. The study showed that bioimaging and biochemical techniques can be effective at detecting and diagnosing cellular injuries incurred by lipid peroxidation.
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Affiliation(s)
- Rabia Alghazeer
- Chemistry Department, Faculty of Science, University of Tripoli, Tripoli 50676, Libya
- Correspondence:
| | - Abdullah A. Burwaiss
- Medicine Department, Faculty of Human Medicine, University of Tripoli, Tripoli 50676, Libya;
| | - Nazlin K. Howell
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK;
| | - Wafa S. Alansari
- Biochemistry Department, Faculty of Science, University of Jeddah, Jeddah 21577, Saudi Arabia;
| | - Ghalia Shamlan
- Department of Food Science and Nutrition, College of Food and agriculture Sciences, King Saud University, Riyadh 11362, Saudi Arabia;
| | - Areej A. Eskandrani
- Chemistry Department, Faculty of Science, Taibah University, Medina 30002, Saudi Arabia;
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Dikiy I, Edupuganti UR, Abzalimov RR, Borbat PP, Srivastava M, Freed JH, Gardner KH. Insights into histidine kinase activation mechanisms from the monomeric blue light sensor EL346. Proc Natl Acad Sci U S A 2019; 116:4963-72. [PMID: 30808807 DOI: 10.1073/pnas.1813586116] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Translation of environmental cues into cellular behavior is a necessary process in all forms of life. In bacteria, this process frequently involves two-component systems in which a sensor histidine kinase (HK) autophosphorylates in response to a stimulus before subsequently transferring the phosphoryl group to a response regulator that controls downstream effectors. Many details of the molecular mechanisms of HK activation are still unclear due to complications associated with the multiple signaling states of these large, multidomain proteins. To address these challenges, we combined complementary solution biophysical approaches to examine the conformational changes upon activation of a minimal, blue-light-sensing histidine kinase from Erythrobacter litoralis HTCC2594, EL346. Our data show that multiple conformations coexist in the dark state of EL346 in solution, which may explain the enzyme's residual dark-state activity. We also observe that activation involves destabilization of the helices in the dimerization and histidine phosphotransfer-like domain, where the phosphoacceptor histidine resides, and their interactions with the catalytic domain. Similar light-induced changes occur to some extent even in constitutively active or inactive mutants, showing that light sensing can be decoupled from activation of kinase activity. These structural changes mirror those inferred by comparing X-ray crystal structures of inactive and active HK fragments, suggesting that they are at the core of conformational changes leading to HK activation. More broadly, our findings uncover surprising complexity in this simple system and allow us to outline a mechanism of the multiple steps of HK activation.
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10
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De Santis A, La Manna S, Krauss IR, Malfitano AM, Novellino E, Federici L, De Cola A, Di Matteo A, D'Errico G, Marasco D. Nucleophosmin-1 regions associated with acute myeloid leukemia interact differently with lipid membranes. Biochim Biophys Acta Gen Subj 2018; 1862:967-978. [PMID: 29330024 DOI: 10.1016/j.bbagen.2018.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 12/04/2017] [Accepted: 01/08/2018] [Indexed: 01/25/2023]
Affiliation(s)
- Augusta De Santis
- Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy; CSGI - Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase, Florence, Italy
| | - Sara La Manna
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", 80134, Naples, Italy
| | - Irene Russo Krauss
- Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy; CSGI - Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase, Florence, Italy
| | - Anna Maria Malfitano
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", 80134, Naples, Italy
| | - Ettore Novellino
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", 80134, Naples, Italy
| | - Luca Federici
- Department of Medical, Oral and Biotechnological Sciences and CeSI-MeT, University of Chieti "G. d'Annunzio", Via dei Vestini 31, 66100 Chieti, Italy
| | - Antonella De Cola
- Department of Medical, Oral and Biotechnological Sciences and CeSI-MeT, University of Chieti "G. d'Annunzio", Via dei Vestini 31, 66100 Chieti, Italy
| | - Adele Di Matteo
- Institute of Molecular Biology and Pathology, CNR, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Gerardino D'Errico
- Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy; CSGI - Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase, Florence, Italy
| | - Daniela Marasco
- Department of Pharmacy, CIRPEB: Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples "Federico II", 80134, Naples, Italy.
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11
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Rozenfeld JHK, Duarte EL, Oliveira TR, Lamy MT. Structural insights on biologically relevant cationic membranes by ESR spectroscopy. Biophys Rev 2017; 9:633-647. [PMID: 28836112 PMCID: PMC5662045 DOI: 10.1007/s12551-017-0304-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 07/28/2017] [Indexed: 12/26/2022] Open
Abstract
Cationic bilayers have been used as models to study membrane fusion, templates for polymerization and deposition of materials, carriers of nucleic acids and hydrophobic drugs, microbicidal agents and vaccine adjuvants. The versatility of these membranes depends on their structure. Electron spin resonance (ESR) spectroscopy is a powerful technique that employs hydrophobic spin labels to probe membrane structure and packing. The focus of this review is the extensive structural characterization of cationic membranes prepared with dioctadecyldimethylammonium bromide or diC14-amidine to illustrate how ESR spectroscopy can provide important structural information on bilayer thermotropic behavior, gel and fluid phases, phase coexistence, presence of bilayer interdigitation, membrane fusion and interactions with other biologically relevant molecules.
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Affiliation(s)
- Julio H K Rozenfeld
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, São Paulo, SP, 04023-062, Brazil
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, R. do Matão 1371, São Paulo, SP, 05508-090, Brazil
| | - Tiago R Oliveira
- Centro de Engenharia, Modelagem e Ciências Sociais Aplicadas, Universidade Federal do ABC, R. Arcturus (Jd Antares), São Bernardo do Campo, SP, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, R. do Matão 1371, São Paulo, SP, 05508-090, Brazil.
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12
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Stipa P, Cipolletti R. DFT calculations as a powerful tool for ESR spin trapping experiments. Magn Reson Chem 2017; 55:559-562. [PMID: 27966232 DOI: 10.1002/mrc.4549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 11/02/2016] [Indexed: 06/06/2023]
Abstract
A combined electron spin resonance (ESR) and density functional theory study has been carried out to obtain deeper insight in the reaction mechanism of the photorearrangement of 3-hydroxyindolic nitrones. Also, in this case, the combination of these techniques constitutes a powerful tool when discriminating between different reaction pathways. In particular, density functional theory calculations played an important role for unraveling the overlapping of signals coming from different species in the ESR spin trapping experiments. In the present study, the computed energies and the corresponding ESR parameters of each possible isomer hypothesized have been considered, taking also into account their different possibilities of intramolecular H-bond formation. However, the results obtained indicate that the possibility of intramolecular H-bonding did not play a determinant role in this case. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Pierluigi Stipa
- SIMAU Department, Chemistry Division, Università Politecnica delle Marche, Ancona, Italy
| | - Roberto Cipolletti
- SIMAU Department, Chemistry Division, Università Politecnica delle Marche, Ancona, Italy
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13
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Lawless MJ, Shimshi A, Cunningham TF, Kinde MN, Tang P, Saxena S. Analysis of Nitroxide-Based Distance Measurements in Cell Extracts and in Cells by Pulsed ESR Spectroscopy. Chemphyschem 2017; 18:1653-1660. [PMID: 28295910 DOI: 10.1002/cphc.201700115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Indexed: 11/10/2022]
Abstract
Measurements of distances in cells by pulsed ESR spectroscopy afford tremendous opportunities to study proteins in native environments that are irreproducible in vitro. However, the in-cell environment is harsh towards the typical nitroxide radicals used in double electron-electron resonance (DEER) experiments. A systematic examination is performed on the loss of the DEER signal, including contributions from nitroxide decay and nitroxide side-chain cleavage. In addition, the possibility of extending the lifetime of the nitroxide radical by use of an oxidizing agent is investigated. Using this oxidizing agent, DEER distance measurements are performed on doubly nitroxide-labeled GB1, the immunoglobulin-binding domain of protein G, at varying incubation times in the cellular environment. It is found that, by comparison of the loss of DEER signal to the loss of the CW spectrum, cleavage of the nitroxide side chain contributes to the loss of DEER signal, which is significantly greater in cells than in cell extracts. Finally, local spin concentrations are monitored at varying incubation times to show the time required for molecular diffusion of a small globular protein within the cellular milieu.
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Affiliation(s)
- Matthew J Lawless
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA
| | - Amit Shimshi
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA
| | - Timothy F Cunningham
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA.,Current address: Department of Chemistry, Hanover College, 484 Ball Dr, Hanover, IN, 47243, USA
| | - Monica N Kinde
- Department of Anesthesiology, University of Pittsburgh School of Medicine, 3501 5th Avenue, Pittsburgh, PA, 15213, USA.,Current address: Division of Basic Sciences, Kansas City University of Medicine and Biosciences, 2901 St. John's Blvd., Joplin, MO, 64804, USA
| | - Pei Tang
- Department of Anesthesiology, University of Pittsburgh School of Medicine, 3501 5th Avenue, Pittsburgh, PA, 15213, USA
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA
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14
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Asami SS, Ishida S, Iwamoto T, Suzuki K, Yamashita M. Isolation and Characterization of Radical Anions Derived from a Boryl-Substituted Diphosphene. Angew Chem Int Ed Engl 2017; 56:1658-1662. [PMID: 28106347 DOI: 10.1002/anie.201611762] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Indexed: 11/08/2022]
Abstract
Radical anions of a diphosphene with two boryl substituents were isolated and characterized by single-crystal X-ray diffraction, electron spin resonance (ESR), and UV/Vis absorption spectroscopy as well as DFT calculations. Structural analysis of the radical anions revealed an elongation of the P=P bond and a contraction of the B-P bonds relative to the neutral diphosphene. The UV/Vis spectra of these radical anions showed a strong absorption in the visible region, which was assigned to SOMO-related transitions on the basis of DFT calculations. The ESR spectra revealed that the hyperfine coupling constant with the phosphorus nuclei is the smallest that has been reported thus far. The results of the DFT calculations furthermore suggest that this should be attributed to a soaking of electron spin to the vacant p orbitals of the boryl substituents.
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Affiliation(s)
- Shun-Suke Asami
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Shintaro Ishida
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - Takeaki Iwamoto
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - Katsunori Suzuki
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Makoto Yamashita
- Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan.,Research Development Initiative, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, T, okyo, 112-8551, Japan
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15
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Lawless MJ, Sarver JL, Saxena S. Nucleotide-Independent Copper(II)-Based Distance Measurements in DNA by Pulsed ESR Spectroscopy. Angew Chem Int Ed Engl 2017; 56:2115-2117. [PMID: 28090713 DOI: 10.1002/anie.201611197] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/14/2016] [Indexed: 01/05/2023]
Abstract
A site-specific Cu2+ binding motif within a DNA duplex for distance measurements by ESR spectroscopy is reported. This motif utilizes a commercially available 2,2'-dipicolylamine (DPA) phosphormadite easily incorporated into any DNA oligonucleotide during initial DNA synthesis. The method only requires the simple post-synthetic addition of Cu2+ without the need for further chemical modification. Notably, the label is positioned within the DNA duplex, as opposed to outside the helical perimeter, for an accurate measurement of duplex distance. A distance of 2.7 nm was measured on a doubly Cu2+ -labeled DNA sequence, which is in exact agreement with the expected distance from both DNA modeling and molecular dynamic simulations. This result suggests that with this labeling strategy the ESR measured distance directly reports on backbone DNA distance, without the need for further modeling. Furthermore, the labeling strategy is structure- and nucleotide-independent.
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Affiliation(s)
- Matthew J Lawless
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA
| | - Jessica L Sarver
- Division of Biological, Chemical, and Environmental Sciences, Westminster College, 319 S Market St., New Wilmington, PA, 16172, USA
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA
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16
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Monzote L, Lackova A, Staniek K, Steinbauer S, Pichler G, Jäger W, Gille L. The antileishmanial activity of xanthohumol is mediated by mitochondrial inhibition. Parasitology 2017; 144:747-59. [PMID: 27938439 DOI: 10.1017/S0031182016002389] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Xanthohumol (Xan) is a natural constituent of human nutrition. Little is known about its actions on leishmanial parasites and their mitochondria as putative target. Therefore, we determined the antileishmanial activity of Xan and resveratrol (Res, as alternative compound with antileishmanial activity) with respect to mitochondria in Leishmania amazonensis promastigotes/amastigotes (LaP/LaA) in comparison with their activity in peritoneal macrophages from mouse (PMM) and macrophage cell line J774A.1 (J774). Mechanistic studies were conducted in Leishmania tarentolae promastigotes (LtP) and mitochondrial fractions isolated from LtP. Xan and Res demonstrated antileishmanial activity in LaA [half inhibitory concentration (IC50): Xan 7 µ m, Res 14 µ m]; while they had less influence on the viability of PMM (IC50: Xan 70 µ m, Res >438 µ m). In contrast to Res, Xan strongly inhibited oxygen consumption in Leishmania (LtP) but not in J774 cells. This was based on the inhibition of the mitochondrial electron transfer complex II/III by Xan, which was less pronounced with Res. Neither Xan nor Res increased mitochondrial superoxide release in LtP, while both decreased the mitochondrial membrane potential in LtP. Bioenergetic studies showed that LtP mitochondria have no spare respiratory capacity in contrast to mitochondria in J774 cells and can therefore much less adapt to stress by mitochondrial inhibitors, such as Xan. These data show that Xan may have antileishmanial activity, which is mediated by mitochondrial inhibition.
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Sandhaus S, Taylor R, Edwards T, Huddleston A, Wooten Y, Venkatraman R, Weber RT, González-Sarrías A, Martin PM, Cagle P, Tse-Dinh YC, Beebe SJ, Seeram N, Holder AA. A novel copper(II) complex identified as a potent drug against colorectal and breast cancer cells and as a poison inhibitor for human topoisomerase IIα. INORG CHEM COMMUN 2016; 64:45-49. [PMID: 26752972 PMCID: PMC4704796 DOI: 10.1016/j.inoche.2015.12.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel complex, [Cu(acetylethTSC)Cl]Cl•0.25C2H5OH 1 (where acetylethTSC = (E)-N-ethyl-2-[1-(thiazol-2-yl)ethylidene]hydrazinecarbothioamide), was shown to have anti-proliferative activity against various colon and aggressive breast cancer cell lines. In vitro studies showed that complex 1 acted as a poison inhibitor of human topoisomerase IIα, which may account for the observed anti-cancer effects.
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Affiliation(s)
- Shayna Sandhaus
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, U.S.A
| | - Rosella Taylor
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, 118 College Drive #5043, Hattiesburg, MS, 39406, U.S.A
| | - Tiffany Edwards
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, 118 College Drive #5043, Hattiesburg, MS, 39406, U.S.A
| | - Alexis Huddleston
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, 118 College Drive #5043, Hattiesburg, MS, 39406, U.S.A
| | - Ykeysha Wooten
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, 118 College Drive #5043, Hattiesburg, MS, 39406, U.S.A
| | - Ramaiyer Venkatraman
- Department of Chemistry and Biochemistry, P.O. Box 17910, 1400 JR Lynch Street, Jackson State University, Jackson, MS 39217, U.S.A
| | - Ralph T Weber
- EPR Division Bruker BioSpin, 44 Manning Road, Billerica, MA 01821, U.S.A
| | - Antonio González-Sarrías
- Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, U.S.A
| | - Patrick M Martin
- North Carolina A and T State University, Department of Biology, Hines Hall, Room 300-B, 1601 East Market St., Greensboro, NC 27411, U.S.A
| | - Patrice Cagle
- North Carolina A and T State University, Department of Biology, Hines Hall, Room 300-B, 1601 East Market St., Greensboro, NC 27411, U.S.A
| | - Yuk-Ching Tse-Dinh
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, U.S.A; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, U.S.A
| | - Stephen J Beebe
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, U.S.A
| | - Navindra Seeram
- Bioactive Botanical Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, U.S.A
| | - Alvin A Holder
- Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Boulevard, Norfolk, VA 23529, U.S.A
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18
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Herrling T, Seifert M, Sandig G, Jung K. The determination of the radical power - an in vitro test for the evaluation of cosmetic products. Int J Cosmet Sci 2015; 38:232-7. [PMID: 26383131 DOI: 10.1111/ics.12279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 09/12/2015] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Cosmetic formulations are influenced by environmental impacts and ageing, resulting in rancidity and change of colour and structure. These changes are caused by free radicals (FRs). The sensitivity of cosmetics generating FRs is a metric for its quality and should be determined. METHODS Electron spin resonance spectroscopy in combination with UV irradiation tested cosmetics such as creams, milks, lotions and fragrances. The probes were directly measured without expensive preparation. RESULTS Nine formulations are tested for its radical generation and ranked corresponding to the radical power. The transformation of the FR properties of three formulations to skin is measured by the radical skin status factor (RSF) method. It shows that the higher the radical power (RP) is, the lower the radical status RSF of skin will be. CONCLUSION The knowledge of the sensitivity of cosmetics to generate FRs is necessary for its stabilization and prevention of potential damages to skin. It is a new way in development of cosmetics which has to be considered.
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Affiliation(s)
- T Herrling
- GEMATRIA Test Lab, Parkstraße 23, 13187, Berlin, Germany
| | - M Seifert
- GEMATRIA Test Lab, Parkstraße 23, 13187, Berlin, Germany
| | - G Sandig
- GEMATRIA Test Lab, Parkstraße 23, 13187, Berlin, Germany
| | - K Jung
- GEMATRIA Test Lab, Parkstraße 23, 13187, Berlin, Germany
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19
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Ruthstein S, Ji M, Shin BK, Saxena S. A simple double quantum coherence ESR sequence that minimizes nuclear modulations in Cu(2+)-ion based distance measurements. J Magn Reson 2015; 257:45-50. [PMID: 26057636 DOI: 10.1016/j.jmr.2015.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 06/04/2023]
Abstract
Double quantum coherence (DQC) ESR is a sensitive method to measure magnetic dipolar interactions between spin labels. However, the DQC experiment on Cu(2+) centers presents a challenge at X-band. The Cu(2+) centers are usually coordinated to histidine residues in proteins. The electron-nuclear interaction between the Cu(2+) ion and the remote nitrogen in the imidazole ring can interfere with the electron-electron dipolar interaction. Herein, we report on a modified DQC experiment that has the advantage of reduced contributions from electron-nuclear interactions, which enhances the resolution of the DQC signal to the electron-electron dipolar modulations. The modified pulse-sequence is verified on Cu(2+)-NO system in a polyalanine-based peptide and on a coupled Cu(2+) system in a polyproline-based peptide. The modified DQC data were compared with the DEER data and good agreement was found.
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Affiliation(s)
- Sharon Ruthstein
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Ming Ji
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Byong-Kyu Shin
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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20
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Gophane DB, Sigurdsson ST. TEMPO-derived spin labels linked to the nucleobases adenine and cytosine for probing local structural perturbations in DNA by EPR spectroscopy. Beilstein J Org Chem 2015; 11:219-27. [PMID: 25815073 PMCID: PMC4362019 DOI: 10.3762/bjoc.11.24] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/15/2015] [Indexed: 02/04/2023] Open
Abstract
Three 2´-deoxynucleosides containing semi-flexible spin labels, namely (T)A, (U)A and (U)C, were prepared and incorporated into deoxyoligonucleotides using the phosphoramidite method. All three nucleosides contain 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) connected to the exocyclic amino group; (T)A directly and (U)A as well as (U)C through a urea linkage. (T)A and (U)C showed a minor destabilization of a DNA duplex, as registered by a small decrease in the melting temperature, while (U)A destabilized the duplex by more than 10 °C. Circular dichroism (CD) measurements indicated that all three labels were accommodated in B-DNA duplex. The mobility of the spin label (T)A varied with different base-pairing partners in duplex DNA, with the (T)A•T pair being the least mobile. Furthermore, (T)A showed decreased mobility under acidic conditions for the sequences (T)A•C and (T)A•G, to the extent that the EPR spectrum of the latter became nearly superimposable to that of (T)A•T. The reduced mobility of the (T)A•C and (T)A•G mismatches at pH 5 is consistent with the formation of (T)AH(+)•C and (T)AH(+)•G, in which protonation of N1 of A allows the formation of an additional hydrogen bond to N3 of C and N7 of G, respectively, with G in a syn-conformation. The urea-based spin labels (U)A and (U)C were more mobile than (T)A, but still showed a minor variation in their EPR spectra when paired with A, G, C or T in a DNA duplex. (U)A and (U)C had similar mobility order for the different base pairs, with the lowest mobility when paired with C and the highest when paired with T.
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Affiliation(s)
- Dnyaneshwar B Gophane
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland
| | - Snorri Th Sigurdsson
- University of Iceland, Department of Chemistry, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland
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21
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Pratt AJ, Shin DS, Merz GE, Rambo RP, Lancaster WA, Dyer KN, Borbat PP, Poole FL 2nd, Adams MW, Freed JH, Crane BR, Tainer JA, Getzoff ED. Aggregation propensities of superoxide dismutase G93 hotspot mutants mirror ALS clinical phenotypes. Proc Natl Acad Sci U S A 2014; 111:E4568-76. [PMID: 25316790 DOI: 10.1073/pnas.1308531111] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Protein framework alterations in heritable Cu, Zn superoxide dismutase (SOD) mutants cause misassembly and aggregation in cells affected by the motor neuron disease ALS. However, the mechanistic relationship between superoxide dismutase 1 (SOD1) mutations and human disease is controversial, with many hypotheses postulated for the propensity of specific SOD mutants to cause ALS. Here, we experimentally identify distinguishing attributes of ALS mutant SOD proteins that correlate with clinical severity by applying solution biophysical techniques to six ALS mutants at human SOD hotspot glycine 93. A small-angle X-ray scattering (SAXS) assay and other structural methods assessed aggregation propensity by defining the size and shape of fibrillar SOD aggregates after mild biochemical perturbations. Inductively coupled plasma MS quantified metal ion binding stoichiometry, and pulsed dipolar ESR spectroscopy evaluated the Cu(2+) binding site and defined cross-dimer copper-copper distance distributions. Importantly, we find that copper deficiency in these mutants promotes aggregation in a manner strikingly consistent with their clinical severities. G93 mutants seem to properly incorporate metal ions under physiological conditions when assisted by the copper chaperone but release copper under destabilizing conditions more readily than the WT enzyme. Altered intradimer flexibility in ALS mutants may cause differential metal retention and promote distinct aggregation trends observed for mutant proteins in vitro and in ALS patients. Combined biophysical and structural results test and link copper retention to the framework destabilization hypothesis as a unifying general mechanism for both SOD aggregation and ALS disease progression, with implications for disease severity and therapeutic intervention strategies.
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Brennessel WW, Ellis JE. Homoleptic 2,2'-bipyridine metalates(-I) of iron and cobalt, one cocrystallized with an anthracene radical anion and the other with neutral anthracene. Acta Crystallogr C Struct Chem 2014; 70:828-32. [PMID: 25093368 DOI: 10.1107/s2053229614017070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 07/24/2014] [Indexed: 11/10/2022]
Abstract
Homoleptic 2,2'-bipyridine (bipy) metalates of iron and cobalt have been synthesized directly from the corresponding homoleptic anthracene metalates. In the iron structure, bis[([2.2.2]cryptand)potassium(I)] tris(2,2'-bipyridine)ferrate(-I) anthracene(-I), [K(C18H36N2O6)]2[Fe(C10H8N2)3](C14H10), the asymmetric unit contains one potassium complex cation in a general position, the Fe center and one and a half bipy ligands of the ferrate complex on a crystallographic twofold axis that includes the Fe atom, and one half of an anthracene radical anion whose other half is generated by a crystallographic inversion center. The cations and anions are well separated and the geometry about the Fe center is essentially octahedral. In the cobalt structure, ([2.2.2]cryptand)potassium(I) bis(2,2'-bipyridine)cobaltate(-I) anthracene hemisolvate tetrahydrofuran (THF) disolvate, [K(C18H36N2O6)][Co(C10H8N2)2]·0.5C14H10·2C4H8O, the asymmetric unit contains the cation, anion, and both cocrystallized THF solvent molecules in general positions, and one half of a cocrystallized anthracene molecule whose other half is generated by a crystallographic inversion center. The cation and anion are well separated and the ligand planes in the cobaltate anion are periplanar. Each anthracene molecule is midway between and is oriented perpendicular to a pair of symmetry-related bipy ligands such that aromatic donor-acceptor interactions may play a role in the packing arrangement. The lengths of the bonds that connect the bipy rings support the assertion that the ligands are bipy radical anions in the iron structure. However, in the case of cobalt, these lengths are between the known ranges for a bipy radical anion and a bipy dianion, and therefore no conclusion can be made from the crystallography alone. One cocrystallized THF solvent molecule in the cobalt structure was modeled as disordered over three positions with appropriate geometric and thermal restraints, which resulted in a refined component mass ratio of 0.412 (4):0.387 (3):0.201 (3).
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Affiliation(s)
- William W Brennessel
- Department of Chemistry, 207 Pleasant Street SE, University of Minnesota, Minneapolis, MN 55455, USA
| | - John E Ellis
- Department of Chemistry, 207 Pleasant Street SE, University of Minnesota, Minneapolis, MN 55455, USA
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Abbas K, Hardy M, Poulhès F, Karoui H, Tordo P, Ouari O, Peyrot F. Detection of superoxide production in stimulated and unstimulated living cells using new cyclic nitrone spin traps. Free Radic Biol Med 2014; 71:281-290. [PMID: 24662195 DOI: 10.1016/j.freeradbiomed.2014.03.019] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 03/11/2014] [Accepted: 03/17/2014] [Indexed: 10/25/2022]
Abstract
Reactive oxygen species (ROS), including superoxide anion and hydrogen peroxide (H2O2), have a diverse array of physiological and pathological effects within living cells depending on the extent, timing, and location of their production. For measuring ROS production in cells, the ESR spin trapping technique using cyclic nitrones distinguishes itself from other methods by its specificity for superoxide and hydroxyl radical. However, several drawbacks, such as the low spin trapping rate and the spontaneous and cell-enhanced decomposition of the spin adducts to ESR-silent products, limit the application of this method to biological systems. Recently, new cyclic nitrones bearing a triphenylphosphonium (Mito-DIPPMPO) or a permethylated β-cyclodextrin moiety (CD-DIPPMPO) have been synthesized and their spin adducts demonstrated increased stability in buffer. In this study, a comparison of the spin trapping efficiency of these new compounds with commonly used cyclic nitrone spin traps, i.e., 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and analogs BMPO, DEPMPO, and DIPPMPO, was performed on RAW 264.7 macrophages stimulated with phorbol 12-myristate 13-acetate. Our results show that Mito-DIPPMPO and CD-DIPPMPO enable a higher detection of superoxide adduct, with a low (if any) amount of hydroxyl adduct. CD-DIPPMPO, especially, appears to be a superior spin trap for extracellular superoxide detection in living macrophages, allowing measurement of superoxide production in unstimulated cells for the first time. The main rationale put forward for this extreme sensitivity is that the extracellular localization of the spin trap prevents the reduction of the spin adducts by ascorbic acid and glutathione within cells.
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Affiliation(s)
- Kahina Abbas
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (UMR CNRS 8601), Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Micael Hardy
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Florent Poulhès
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Hakim Karoui
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Paul Tordo
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Olivier Ouari
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Fabienne Peyrot
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (UMR CNRS 8601), Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France; ESPE de l׳Académie de Paris, Université Paris Sorbonne, 75016 Paris, France.
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Morra E, Giamello E, Chiesa M. Probing the redox chemistry of titanium silicalite-1: formation of tetrahedral Ti3+ centers by reaction with triethylaluminum. Chemistry 2014; 20:7381-8. [PMID: 24824439 DOI: 10.1002/chem.201304139] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 11/21/2013] [Indexed: 11/10/2022]
Abstract
Transition-metal ions with open-shell configurations hold promise in the development of novel coordination chemistry and potentially unprecedented redox catalysis. Framework-substituted Ti(3+) ions with tetrahedral coordination are generated by reductive activation of titanium silicalite-1 with triethylaluminum, an indispensable co-catalyst for heterogeneous Ziegler-Natta polymerization catalysts. Continuous-wave and pulse electron paramagnetic resonance methods are applied to unravel details on the local environment of the reduced transition metal-ions, which are shown to be part of the silica framework by detection of (29)Si hyperfine interactions. The chemical accessibility of the reduced sites is probed using ammonia as probe molecule. Evidence is found for the coordination of a single ammonia molecule. Comparison to similar systems, such as TiAlPO-5, reveals clear differences in the coordination chemistry of the reduced Ti sites in the two solids, which may be understood considering the different electronic properties of the solid frameworks.
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Affiliation(s)
- Elena Morra
- Department of Chemistry, University of Torino, Via Giuria, 7, 10125 Torino (Italy), Fax: (+39) 0116707855; Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven (The Netherlands)
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Bézière N, Hardy M, Poulhès F, Karoui H, Tordo P, Ouari O, Frapart YM, Rockenbauer A, Boucher JL, Mansuy D, Peyrot F. Metabolic stability of superoxide adducts derived from newly developed cyclic nitrone spin traps. Free Radic Biol Med 2014; 67:150-8. [PMID: 24161442 DOI: 10.1016/j.freeradbiomed.2013.10.812] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 09/20/2013] [Accepted: 10/16/2013] [Indexed: 11/24/2022]
Abstract
Reactive oxygen species are by-products of aerobic metabolism involved in the onset and evolution of various pathological conditions. Among them, the superoxide radical is of special interest as the origin of several damaging species such as H2O2, hydroxyl radical, or peroxynitrite (ONOO(-)). Spin trapping coupled with ESR is a method of choice to characterize these species in chemical and biological systems and the metabolic stability of the spin adducts derived from reaction of superoxide and hydroxyl radicals with nitrones is the main limit to the in vivo application of the method. Recently, new cyclic nitrones bearing a triphenylphosphonium or permethylated β-cyclodextrin moiety have been synthesized and their spin adducts demonstrated increased stability in buffer. In this article, we studied the stability of the superoxide adducts of four new cyclic nitrones in the presence of liver subcellular fractions and biologically relevant reductants using an original setup combining a stopped-flow device and an ESR spectrometer. The kinetics of disappearance of the spin adducts were analyzed using an appropriate simulation program. Our results highlight the interest of the new spin trapping agents CD-DEPMPO and CD-DIPPMPO for specific detection of superoxide with high stability of the superoxide adducts in the presence of liver microsomes.
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Affiliation(s)
- Nicolas Bézière
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (UMR CNRS 8601), Université Paris Descartes, 75006 Paris, France
| | - Micael Hardy
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Florent Poulhès
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Hakim Karoui
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Paul Tordo
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Olivier Ouari
- Aix-Marseille Université, CNRS, ICR UMR 7273, 13397 Marseille Cedex 20, France
| | - Yves-Michel Frapart
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (UMR CNRS 8601), Université Paris Descartes, 75006 Paris, France
| | - Antal Rockenbauer
- Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Jean-Luc Boucher
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (UMR CNRS 8601), Université Paris Descartes, 75006 Paris, France
| | - Daniel Mansuy
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (UMR CNRS 8601), Université Paris Descartes, 75006 Paris, France
| | - Fabienne Peyrot
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques (UMR CNRS 8601), Université Paris Descartes, 75006 Paris, France; IUFM de Paris, Université Paris Sorbonne, 75016 Paris, France.
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Affiliation(s)
- Jianbing Jiang
- School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000 (China)
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Lewis NA, Liu F, Seymour L, Magnusen A, Erves TR, Arca JF, Beckford FA, Venkatraman R, González-Sarrías A, Fronczek FR, Vanderveer DG, Seeram NP, Liu A, Jarrett WL, Holder AA. Synthesis, characterization, and preliminary in vitro studies of vanadium(IV) complexes with a Schiff base and thiosemicarbazones as mixed-ligands. Eur J Inorg Chem 2011; 2012:664-677. [PMID: 23904789 DOI: 10.1002/ejic.201100898] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
[VO(Sal-L-tryp)(H2O)] 1 (where sal-L-tryp = N-salicylidene-L-tryptophanate) was used as a precursor to produce the novel complexes, [VO(Sal-L-tryp)(MeATSC)].1.5C2H5OH 2 (where MeATSC = 9-Anthraldehyde-N(4)-methylthiosemicarbazone), [VO(Sal-L-tryp)(N-Ethhymethohcarbthio)].H2O 3 (where N-Ethhymethohcarbthio = (E)-N-ethyl-2-(4-hydroxy-3-methoxybenzylidene)hydrazinecarbothioamide), and [VO(Sal-L-tryp)(acetylethTSC)].C2H5OH 4 (where acetylethTSC = (E)-N-ethyl-2-(1-(thiazol-2-yl)ethylidene)hydrazinecarbothioamide), by reaction with the respective thiosemicarbazone. The chemical and structural properties of these ligands and complexes were characterised by elemental analysis, ESI MS, FT-IR, UV-visible, ESR, 1H and 13C NMR spectroscopy, and X-ray crystallography. DMSO and DMSO-d6 solutions of compounds 1-4 were oxidised in air to produce vanadium(V) species which were verified by ESI MS and 51V NMR spectroscopy. Anti-cancer properties of compounds 2-4 were examined with three colon cancer cell lines, HTC-116, Caco-2, and HT-29, and also with non-cancerous colonic myofibroblasts, CCD18-Co. Compounds 2-3 exhibited less inhibitory effects in the CCD-18Co cells, indicating a possible cytotoxic selectivity towards colon cancer cells. In general, those compounds which exhibited anti-proliferative activity on cancer cells, but did not affect non-cancerous cells, may have a potential in chemotherapy.
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Affiliation(s)
- Nerissa A Lewis
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, 118 College Drive, # 5043, Hattiesburg, Mississippi 39406-0001
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