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Abrar Siddiquee M, Saraswat J, Ud Din Parray M, Singh P, Bargujar S, Patel R. Spectroscopic and DFT study of imidazolium based ionic liquids with broad spectrum antibacterial drug levofloxacin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 285:121803. [PMID: 36095856 DOI: 10.1016/j.saa.2022.121803] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 08/14/2022] [Accepted: 08/27/2022] [Indexed: 06/15/2023]
Abstract
Herein, we have shown the interaction of levofloxacin (LVF) with two imidazolium based ionic liquids (ILs), 1-butly-3-methylimidazolium chloride ([Bmim][Cl]) and 1-decyl-3-methylimidazolium chloride ([Dmim][Cl]) by utilising spectroscopic techniques along with computational approach. Both [Bmim][Cl] and [Dmim][Cl] quenched the fluorescence emission of LVF suggesting complex formation between ILs and the drug. The steady-state and time-resolve fluorescence studies revealed that the quenching of fluorescence emission of LVF in the presence of [Bmim][Cl] and [Dmim][Cl], which signified the non-fluorescent complex formation between LVF and ILs. The complex formation between LVF and ILs were also validated by the UV-visible spectroscopy method. The cyclic voltammetry (CV) results further suggest the strong interaction between LVF and ILs. The estimated binding constant (Kb) and free energy change (ΔG) parameters shows the substantial binding of LVF with both the ILs and spontaneous in nature. The value suggested that LVF have stronger binding with [Dmim][Cl] than [Bmim][Cl]. Further, in order to support the results classical density functional theory (DFT) model was performed. The DFT calculations were utilized to explore the 3D structure and the molecular orbitals (HOMO and LUMO) of ILs, LVF and their complexes using Gaussian 09 software. The aggregate size (Dh) and zeta potential of ILs and IL-drug complexes were determined by dynamic light scattering (DLS) and zeta potential in aqueous medium.
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Affiliation(s)
- Md Abrar Siddiquee
- Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Juhi Saraswat
- Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Mehraj Ud Din Parray
- Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Prashant Singh
- Department of Chemistry, ARSD College, Delhi University, New Delhi 110021, India
| | - Savita Bargujar
- Department of Chemistry, Ramjas College, Delhi University, New Delhi 110007, India
| | - Rajan Patel
- Biophysical Chemistry Laboratory, Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India.
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Dilxat D, Liang T, Wang Y, Habibul N. Insights into the interaction mechanism of ofloxacin and functionalized nano-polystyrene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 284:121792. [PMID: 36088742 DOI: 10.1016/j.saa.2022.121792] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 08/19/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
Nano-plastics (NPs), an emerging contaminant in the environment, have a larger specific surface area and can act as a carrier of other contaminants. Thus, insights into the interaction mechanisms between NPs and other pollutants are crucial for the assessment of environmental impacts of NPs in the ecosystems. In this study, the interaction mechanism between NPs and ofloxacin (OFL) were investigated via kinetics, fluorescence quenching, and two-dimensional correlation spectroscopy (2DCOS). The adsorption kinetics of OFL on carboxyl-modified polystyrene (PS-COOH) and amine modified polystyrene (PS-NH2) closely fitted the pseudo-second-order kinetics model (R2 = 0.99). Adsorption kinetics indicated that chemical adsorption is dominant mechanism, and the Fourier Transform Infrared Spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS) results showed that the electronic interaction, π-π, and H-binding were also involved in the adsorption process. OFL showed strong fluorescence quenching in the presence of NPs. Stern-Volmer quenching was negatively related with the temperature, which was dominated by the static type of quenching. 2DCOS indicated that the π-π conjugation was dominant in the interaction process, and the interaction process was dependent on the solution pH and salinity. Overall, this work provides new insights into the interaction mechanism of NPs and antibiotics in the aquatic ecosystems.
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Affiliation(s)
- Dilnur Dilxat
- College of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi 830054, China; Xinjiang Key Laboratory of Energy Storage and Photoelectrocatalytic Materials, Urumqi 830054, China
| | - Ting Liang
- College of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi 830054, China; Xinjiang Key Laboratory of Energy Storage and Photoelectrocatalytic Materials, Urumqi 830054, China
| | - Yun Wang
- College of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi 830054, China; Xinjiang Key Laboratory of Energy Storage and Photoelectrocatalytic Materials, Urumqi 830054, China
| | - Nuzahat Habibul
- College of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi 830054, China; Xinjiang Key Laboratory of Energy Storage and Photoelectrocatalytic Materials, Urumqi 830054, China.
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Golovnev NN, Gerasimova MA, Molokeev MS, Plyaskin ME, Baronin ME. Photoluminescence of pefloxacindi-ium manganese(II) and zinc(II) tetrahalides. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Żamojć K, Bylińska I, Wiczk W, Chmurzyński L. Fluorescence Quenching Studies on the Interactions between Chosen Fluoroquinolones and Selected Stable TEMPO and PROXYL Nitroxides. Int J Mol Sci 2021; 22:ijms22020885. [PMID: 33477329 PMCID: PMC7830230 DOI: 10.3390/ijms22020885] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/07/2021] [Accepted: 01/13/2021] [Indexed: 11/16/2022] Open
Abstract
The influence of the stable 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) nitroxide and its six C4-substituted derivatives, as well as two C3-substituted analogues of 2,2,5,5-tetramethylpyrrolidynyl-N-oxyl (PROXYL) nitroxide on the chosen fluoroquinolone antibiotics (marbofloxacin, ciprofloxacin, danofloxacin, norfloxacin, enrofloxacin, levofloxacin and ofloxacin), has been examined in aqueous solutions by UV absorption as well as steady-state and time-resolved fluorescence spectroscopies. The mechanism of fluorescence quenching has been specified and proved to be purely dynamic (collisional) for all the studied systems, which was additionally confirmed by temperature dependence experiments. Moreover, the selected quenching parameters—that is, Stern–Volmer quenching constants and bimolecular quenching rate constants—have been determined and explained. The possibility of electron transfer was ruled out, and the quenching was found to be diffusion-limited, being a result of the increase in non-radiative processes. Furthermore, as the chosen nitroxides affected the fluorescence of fluoroquinolone antibiotics in different ways, an influence of the structure and the type of substituents in the molecules of both fluoroquinolones and stable radicals on the quenching efficiency has been determined and discussed. Finally, the impact of the solvent’s polarity on the values of bimolecular quenching rate constants has been explained. The significance of the project comes from many applications of nitroxides in chemistry, biology and industry.
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Drzeżdżon J, Jacewicz D, Sielicka A, Chmurzyński L. A review of new approaches to analytical methods to determine the structure and morphology of polymers. Trends Analyt Chem 2019. [DOI: 10.1016/j.trac.2019.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Dihydroxy-Substituted Coumarins as Fluorescent Probes for Nanomolar-Level Detection of the 4-Amino-TEMPO Spin Label. Int J Mol Sci 2019; 20:ijms20153802. [PMID: 31382639 PMCID: PMC6696051 DOI: 10.3390/ijms20153802] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/18/2022] Open
Abstract
This paper reports on dihydroxycoumarins as fluorescent probes suitable for the detection and determination of the nitroxide radical, namely 4-amino-TEMPO. Since 4-amino-TEMPO is used as a spin label for the detection of various radicals and damage caused by these species, its determination under physiological conditions might help us to understand the mechanism of the oxidative stress. Among different coumarins studied, only dihydroxy-substituted derivatives show high sensitivity, specificity, and selectivity for the nitroxide radical. In this assay, dihydroxy-substituted coumarins under the action of 4-amino-TEMPO show a very fast and significant increase in fluorescence intensity and lifetime. Among them 6,7-dihydroxycoumarin (esculetin) exhibits the strongest fluorescence enhancement (up to 40 times), with an estimated limit of detection equal to 16.7 nM—a significantly lower value when compared with UV-Vis or electron paramagnetic resonance (EPR) spectroscopy. The method is characterized by an easy procedure of sample preparation and very short time of analysis. The mechanism of the interaction between 6,7-dihydroxycoumarin and 4-amino-TEMPO has been examined with the use of a series of complementary techniques, such as steady-state and time-resolved fluorescence spectroscopy, UV-Vis spectroscopy, electron paramagnetic resonance spectroscopy, potentiometric titration, and high-performance liquid chromatography. It has been proven that the only route of the reaction in the system studied is a proton transfer from the molecule of esculetin to the amino group of the nitroxide. Biological studies performed on prostate cancer cells, breast cancer cells, and normal skin fibroblasts revealed significant anticancer properties of 6,7-dihydroxycoumarin, which caused a considerable decrease in the viability and number of cancer cells, and affected their morphology, contrary to normal fibroblasts. Furthermore, the experiment performed on prostate cancer cells showed that fluorescence emission of esculetin is closely related to intracellular pH—the higher pH, the higher observed fluorescence intensity (in accordance with a chemical experiment). On the other hand, the studies performed in different pH levels revealed that when pH of the solution increases, the observed fluorescence intensity enhancement under the action of 4-amino-TEMPO decreases (better sensing properties of esculetin towards the nitroxide in lower pH).
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Drzeżdżon J, Jacewicz D, Chmurzyński L. The impact of environmental contamination on the generation of reactive oxygen and nitrogen species - Consequences for plants and humans. ENVIRONMENT INTERNATIONAL 2018; 119:133-151. [PMID: 29957355 DOI: 10.1016/j.envint.2018.06.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/15/2018] [Accepted: 06/16/2018] [Indexed: 05/23/2023]
Abstract
Environmental contaminants, such as heavy metals, nanomaterials, and pesticides, induce the formation of reactive oxygen and nitrogen species (RONS). Plants interact closely with the atmosphere, water, and soil, and consequently RONS intensely affect their biochemistry. For the past 30 years researchers have thoroughly examined the role of RONS in plant organisms and oxidative modifications to cellular components. Hydrogen peroxide, superoxide anion, nitrogen(II) oxide, and hydroxyl radicals have been found to take part in many metabolic pathways. In this review the various aspects of the oxidative stress induced by environmental contamination are described based on an analysis of literature. The review reinforces the contention that RONS play a dual role, that is, both a deleterious and a beneficial one, in plants. Environmental contamination affects human health, also, and so we have additionally described the impact of RONS on the coupled human - environment system.
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Affiliation(s)
- Joanna Drzeżdżon
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Dagmara Jacewicz
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
| | - Lech Chmurzyński
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
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Żamojć K, Wiczk W, Chmurzyński L. The influence of the type of substituents and the solvent on the interactions between different coumarins and selected TEMPO analogues – Fluorescence quenching studies. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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9
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Makowska J, Żamojć K, Wyrzykowski D, Wiczk W, Chmurzyński L. Copper(II) complexation by fragment of central part of FBP28 protein from Mus musculus. Biophys Chem 2018; 241:55-60. [PMID: 30107307 DOI: 10.1016/j.bpc.2018.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/04/2018] [Accepted: 08/05/2018] [Indexed: 01/18/2023]
Abstract
Steady-state and time-resolved fluorescence spectroscopy, UV spectrophotometry and isothermal titration calorimetry techniques were used to study the coordinating properties of the 17aa peptide fragment (D17) derived from the central part of the mouse formin binding protein (FBP28 with the PDB code: 1E0L) towards Cu2+ ions. All the measurements were run in the 2-(N-morpholino)ethanesulfonic acid buffer (20 mM, pH 6.0). Under experimental conditions the formation of the 1:1 complex of Cu2+ ions with D17 is an entropy-driven process. Cu2+ ions cause the static fluorescence quenching of the peptide studied through the formation of a non-fluorescent complex. Furthermore, the thermal stability of D17 was discussed based on the results obtained from differential scanning fluorimetry (nanoDSF) data.
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Affiliation(s)
- Joanna Makowska
- Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-308 Gdansk, Poland
| | - Krzysztof Żamojć
- Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-308 Gdansk, Poland.
| | - Dariusz Wyrzykowski
- Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-308 Gdansk, Poland
| | - Wiesław Wiczk
- Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-308 Gdansk, Poland
| | - Lech Chmurzyński
- Faculty of Chemistry, University of Gdansk, ul. Wita Stwosza 63, 80-308 Gdansk, Poland
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Drzeżdżon J, Jacewicz D, Wyrzykowski D, Inkielewicz-Stępniak I, Sikorski A, Tesmar A, Chmurzyński L. Structures, physicochemical and cytoprotective properties of new oxidovanadium(IV) complexes -[VO(mIDA)(dmbipy)]·1.5H 2 O and [VO(IDA)(dmbipy)]·2H 2 O. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.04.096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Makowska J, Żamojć K, Wyrzykowski D, Żmudzińska W, Uber D, Wierzbicka M, Wiczk W, Chmurzyński L. Probing the binding of Cu(2+) ions to a fragment of the Aβ(1-42) polypeptide using fluorescence spectroscopy, isothermal titration calorimetry and molecular dynamics simulations. Biophys Chem 2016; 216:44-50. [PMID: 27398680 DOI: 10.1016/j.bpc.2016.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/22/2016] [Accepted: 06/30/2016] [Indexed: 12/19/2022]
Abstract
Steady-state and time-resolved fluorescence quenching measurements supported by isothermal titration calorimetry (ITC) and molecular dynamics simulations (MD), with the NMR-derived restraints, were used to investigate the interactions of Cu(2+) ions with a fragment of the Aβ(1-42) polypeptide, Aβ(5-16) with the following sequence: Ac-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Lys-NH2, denoted as HZ1. The studies presented in this paper, when compared with our previous results (Makowska et al., Spectrochim. Acta A 153: 451-456), show that the affinity of the peptide to metal ions is conformation-dependent. All the measurements were carried out in 20mM 2-(N-morpholino)ethanesulfonic acid (MES) buffer solution, pH6.0. The Stern-Volmer equations, along with spectroscopic observations, were used to determine the quenching and binding parameters. The obtained results unequivocally suggest that Cu(2+) ions quench the fluorescence of HZ1 only through a static quenching mechanism, in contrast to the fragment from the N-terminal part of the FPB28 protein, with sequence Ac-Tyr-Lys-Thr-Ala-Asp-Gly-Lys-Thr-Tyr- NH2 (D9) and its derivative with a single point mutation: Ac-Tyr-Lys-Thr-Ala-Asn-Gly-Lys-Thr-Tyr- NH2 (D9_M), where dynamic quenching occurred. The thermodynamic parameters (ΔITCH, ΔITCS) for the interactions between Cu(2+) ions and the HZ1 peptide were determined from the calorimetric data. The conditional thermodynamic parameters suggest that, under the experimental conditions, the formation of the Cu(2+)-HZ1 complex is both an enthalpy and entropy driven process.
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Affiliation(s)
- Joanna Makowska
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Krzysztof Żamojć
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland.
| | - Dariusz Wyrzykowski
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Wioletta Żmudzińska
- Intercollegiate Faculty of Biotechnology UG&MUG, University of Gdańsk, ul. Abrahama 58, 80-307 Gdańsk, Poland
| | - Dorota Uber
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Małgorzata Wierzbicka
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Wiesław Wiczk
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Lech Chmurzyński
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
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Makowska J, Żamojć K, Wyrzykowski D, Uber D, Wierzbicka M, Wiczk W, Chmurzyński L. Binding of Cu(II) ions to peptides studied by fluorescence spectroscopy and isothermal titration calorimetry. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2016; 153:451-6. [PMID: 26363471 DOI: 10.1016/j.saa.2015.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 05/12/2023]
Abstract
Steady-state and time-resolved fluorescence quenching measurements supported by Isothermal Titration Calorimetry (ITC) were used to study the interactions of Cu(2+) with four peptides. Two of them were taken from the N-terminal part of the FBP28 protein (formin binding protein) WW domain: Tyr-Lys-Thr-Ala-Asp-Gly-Lys-Thr-Tyr-NH2 (D9) and its mutant Tyr-Lys-Thr-Ala-Asn-Gly-Lys-Thr-Tyr-NH2 (D9_M) as well as two mutated peptides from the B3 domain of the immunoglobulin binding protein G derived from Streptococcus: Asp-Val-Ala-Thr-Tyr-Thr-NH2 (J1) and Glu-Val-Ala-Thr-Tyr-Thr-NH2 (J2). The measurements were carried out at 298.15K in 20mM 2-(N-morpholino)ethanesulfonic acid (MES) buffer solution with a pH of 6. The fluorescence of all peptides was quenched by Cu(2+) ions. The stoichiometry, conditional stability constants and thermodynamic parameters for the interactions of the Cu(2+) ions with D9 and D9_M were determined from the calorimetric data. The values of the conditional stability constants were additionally determined from fluorescence quenching measurements and compared with those obtained from calorimetric studies. There was a good correlation between data obtained from the two techniques. On the other hand, the studies revealed that J1 and J2 do not exhibit an affinity towards metal ions. The obtained results prove that fluorescence quenching experiments may be successfully used in order to determine stability constants of complexes with fluorescent ligands. Finally, based on the obtained results, the coordinating properties of the peptides towards the Cu(2+) ions are discussed.
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Affiliation(s)
- Joanna Makowska
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Krzysztof Żamojć
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland.
| | - Dariusz Wyrzykowski
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Dorota Uber
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Małgorzata Wierzbicka
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Wiesław Wiczk
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Lech Chmurzyński
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
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Żamojć K, Wiczk W, Zaborowski B, Jacewicz D, Chmurzyński L. Fluorescence quenching of 7-amino-4-methylcoumarin by different TEMPO derivatives. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 136 Pt C:1875-80. [PMID: 25467682 DOI: 10.1016/j.saa.2014.10.102] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/17/2014] [Accepted: 10/23/2014] [Indexed: 05/24/2023]
Abstract
The fluorescence quenching of 7-amino-4-methylcoumarin by different TEMPO derivatives was studied in aqueous solutions with the use of steady-state, time-resolved fluorescence spectroscopy as well as UV-VIS absorption spectroscopy methods. In order to distinguish each TEMPO derivative from the others and to understand the mechanism of quenching, the absorption and fluorescence emission spectra as well as decays of the fluorescence of 7-amino-4-methylcoumarin were registered as a function of each TEMPO derivative concentration. There were no deviations from a linearity in the Stern-Volmer plots (determined from both, steady-state and time-resolved measurements). The fluorescence quenching mechanism was found to be entirely collisional, what was additionally confirmed by the registration of Stern-Volmer plots at 5 temperatures ranging from 15 to 55°C. Based on theoretical calculations of molecular radii and ionization potentials of all TEMPO derivatives the mechanism of electron transfer was rejected. The fluorescence quenching which was being studied seems to be diffusion-limited and caused by the increase of non-radiative processes, such as an internal conversion and an intersystem crossing. The Stern-Volmer quenching constants and bimolecular quenching constants were determined at the room temperature for all TEMPO derivatives studied. Among all TEMPO derivatives studied TEMPO-4-amino-4-carboxylic acid (TOAC) was found to be the most effective quencher of 7-amino-4-methylcoumarin fluorescence (kq for TOAC was approximately 1.5 higher than kq for other TEMPO compounds studied). The findings demonstrate the possibility of developing an analytical method for the quantitative determination of TOAC, which incorporation into membrane proteins may provide a direct detection of peptide backbone dynamics.
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Affiliation(s)
- Krzysztof Żamojć
- University of Gdansk, Faculty of Chemistry, Wita Stwosza 63, 80-308 Gdansk, Poland.
| | - Wiesław Wiczk
- University of Gdansk, Faculty of Chemistry, Wita Stwosza 63, 80-308 Gdansk, Poland
| | | | - Dagmara Jacewicz
- University of Gdansk, Faculty of Chemistry, Wita Stwosza 63, 80-308 Gdansk, Poland
| | - Lech Chmurzyński
- University of Gdansk, Faculty of Chemistry, Wita Stwosza 63, 80-308 Gdansk, Poland
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Żamojć K, Zdrowowicz M, Wiczk W, Jacewicz D, Chmurzyński L. Dihydroxycoumarins as highly selective fluorescent probes for the fast detection of 4-hydroxy-TEMPO in aqueous solution. RSC Adv 2015. [DOI: 10.1039/c5ra07283b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Dihydroxycoumarins are found to be highly selective fluorescent probes for the fast detection of 4-hydroxy-TEMPO in aqueous solution.
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Affiliation(s)
- K. Żamojć
- University of Gdansk
- Faculty of Chemistry
- 80-308 Gdansk
- Poland
| | - M. Zdrowowicz
- University of Gdansk
- Faculty of Chemistry
- 80-308 Gdansk
- Poland
| | - W. Wiczk
- University of Gdansk
- Faculty of Chemistry
- 80-308 Gdansk
- Poland
| | - D. Jacewicz
- University of Gdansk
- Faculty of Chemistry
- 80-308 Gdansk
- Poland
| | - L. Chmurzyński
- University of Gdansk
- Faculty of Chemistry
- 80-308 Gdansk
- Poland
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