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Haeri H, Eisermann J, Schimm H, Büscher A, Hoyer P, Hinderberger D. Profound Changes in Functional Structure and Dynamics of Serum Albumin in Children with Nephrotic Syndrome: An Exploratory Research Study. J Med Chem 2023; 66:12115-12129. [PMID: 37648246 PMCID: PMC10510392 DOI: 10.1021/acs.jmedchem.3c00680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Indexed: 09/01/2023]
Abstract
Patients with nephrotic syndrome (NS) suffer from urinary loss of albumin. As a cause, previous studies focused on the glomerular filter rather than analyzing the molecular properties of albumin itself. Later one was initiated by clinical observations indicating unexplained molecular alterations of human serum albumin (HSA) in an NS pediatric patient. Therefore, we examined serum from eight pediatric patients with steroid-sensitive and -resistant NS and compared it with serum from healthy subjects as well as commercial HSA. We used dynamic and electrophoretic light scattering to characterize the protein size and effective surface charge and electron paramagnetic resonance spectroscopy to measure the local environment and binding dynamics of up to seven fatty acids associated with HSA. Our findings suggest that pronounced differences in binding behavior and surface charge of HSA could enhance their filtration through the GBM, leading to direct toxicity of HSA to podocytes.
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Affiliation(s)
- Haleh
H. Haeri
- Physical
Chemistry, Complex Self-Organizing Systems, Martin Luther University
Halle-Wittenberg, Institute of Chemistry, Von Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Jana Eisermann
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Ln, W12 0BZ London, U.K.
| | - Heike Schimm
- Physical
Chemistry, Complex Self-Organizing Systems, Martin Luther University
Halle-Wittenberg, Institute of Chemistry, Von Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Anja Büscher
- Universitätsklinikum
Essen (AöR), Klinik für Kinderheilkunde II, Zentrum
für Kinder- und Jugendmedizin, Hufelandstraße 55, D-45147 Essen, Germany
| | - Peter Hoyer
- Universitätsklinikum
Essen (AöR), Klinik für Kinderheilkunde II, Zentrum
für Kinder- und Jugendmedizin, Hufelandstraße 55, D-45147 Essen, Germany
| | - Dariush Hinderberger
- Physical
Chemistry, Complex Self-Organizing Systems, Martin Luther University
Halle-Wittenberg, Institute of Chemistry, Von Danckelmann-Platz 4, 06120 Halle (Saale), Germany
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2
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Tran VA, Teucher M, Galazzo L, Sharma B, Pongratz T, Kast SM, Marx D, Bordignon E, Schnegg A, Neese F. Dissecting the Molecular Origin of g-Tensor Heterogeneity and Strain in Nitroxide Radicals in Water: Electron Paramagnetic Resonance Experiment versus Theory. J Phys Chem A 2023; 127:6447-6466. [PMID: 37524058 PMCID: PMC10424240 DOI: 10.1021/acs.jpca.3c02879] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/01/2023] [Indexed: 08/02/2023]
Abstract
Nitroxides are common EPR sensors of microenvironmental properties such as polarity, numbers of H-bonds, pH, and so forth. Their solvation in an aqueous environment is facilitated by their high propensity to form H-bonds with the surrounding water molecules. Their g- and A-tensor elements are key parameters to extracting the properties of their microenvironment. In particular, the gxx value of nitroxides is rich in information. It is known to be characterized by discrete values representing nitroxide populations previously assigned to have different H-bonds with the surrounding waters. Additionally, there is a large g-strain, that is, a broadening of g-values associated with it, which is generally correlated with environmental and structural micro-heterogeneities. The g-strain is responsible for the frequency dependence of the apparent line width of the EPR spectra, which becomes evident at high field/frequency. Here, we address the molecular origin of the gxx heterogeneity and of the g-strain of a nitroxide moiety (HMI: 2,2,3,4,5,5-hexamethylimidazolidin-1-oxyl, C9H19N2O) in water. To treat the solvation effect on the g-strain, we combined a multi-frequency experimental approach with ab initio molecular dynamics simulations for structural sampling and quantum chemical EPR property calculations at the highest realistically affordable level, including an explicitly micro-solvated HMI ensemble and the embedded cluster reference interaction site model. We could clearly identify the distinct populations of the H-bonded nitroxides responsible for the gxx heterogeneity experimentally observed, and we dissected the role of the solvation shell, H-bond formation, and structural deformation of the nitroxide in the creation of the g-strain associated with each nitroxide subensemble. Two contributions to the g-strain were identified in this study. The first contribution depends on the number of hydrogen bonds formed between the nitroxide and the solvent because this has a large and well-understood effect on the gxx-shift. This contribution can only be resolved at high resonance frequencies, where it leads to distinct peaks in the gxx region. The second contribution arises from configurational fluctuations of the nitroxide that necessarily lead to g-shift heterogeneity. These contributions cannot be resolved experimentally as distinct resonances but add to the line broadening. They can be quantitatively analyzed by studying the apparent line width as a function of microwave frequency. Interestingly, both theory and experiment confirm that this contribution is independent of the number of H-bonds. Perhaps even more surprisingly, the theoretical analysis suggests that the configurational fluctuation broadening is not induced by the solvent but is inherently present even in the gas phase. Moreover, the calculations predict that this broadening decreases upon solvation of the nitroxide.
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Affiliation(s)
- Van Anh Tran
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Markus Teucher
- Max-Planck-Institut
für Chemische Energiekonversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Laura Galazzo
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
- Faculty
of Chemistry and Biochemistry, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Bikramjit Sharma
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Tim Pongratz
- Fakultät
für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Stefan M. Kast
- Fakultät
für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Dominik Marx
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Enrica Bordignon
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
- Faculty
of Chemistry and Biochemistry, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Alexander Schnegg
- Max-Planck-Institut
für Chemische Energiekonversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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3
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Coppola F, Cimino P, Perrella F, Crisci L, Petrone A, Rega N. Electronic and Vibrational Manifold of Tetracyanoethylene-Chloronaphthalene Charge Transfer Complex in Solution: Insights from TD-DFT and Ab Initio Molecular Dynamics. J Phys Chem A 2022; 126:7179-7192. [PMID: 36174118 PMCID: PMC9574931 DOI: 10.1021/acs.jpca.2c05001] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/17/2022] [Indexed: 11/29/2022]
Abstract
The interplay between light absorption and the molecular environment has a central role in the observed photophysics of a wide range of photoinduced chemical and biological phenomena. The understanding of the interplay between vibrational and electronic transitions is the focus of this work, since it can provide a rationale to tune the optical properties of charge transfer (CT) materials used for technological applications. A clear description of these processes poses a nontrivial challenge from both the theoretical and experimental points of view, where the main issue is how to accurately describe and probe drastic changes in the electronic structure and the ultrafast molecular relaxation and dynamics. In this work we focused on the intermolecular CT reaction that occurs upon photon absorption in a π-stacked model system in dichloromethane solution, in which the 1-chloronaphthalene (1ClN) acts as the electron donor and tetracyanoethylene (TCNE) is the electron acceptor. Density functional theory calculations have been carried out to characterize both the ground-state properties and more importantly the low-lying CT electronic transition, and excellent agreement with recently available experimental results [Mathies, R. A.; et al. J. Phys. Chem. A 2018, 122 (14), 3594] was obtained. The minima of the ground state and first singlet excited state have been accurately characterized in terms of spatial arrangements and vibrational Raman frequencies, and the CT natures of the first two low-lying electronic transitions in the absorption spectra have been addressed and clarified too. Finally, by modeling the possible coordination sites of the TCNE electron acceptor with respect to monovalent ions (Na+, K+) in an implicit solution of acetonitrile, we find that TCNE can accommodate a counterion in two different arrangements, parallel and orthogonal to the C═C axis, leading to the formation of a contact ion pair. The nature of the counterion and its relative position entail structural modifications of the TCNE radical anion, mainly the central C═C and C≡N bonds, compared to the isolated case. An important red shift of the C═C stretching frequency was observed when the counterion is orthogonal to the double bond, to a greater extent for Na+. On the contrary, in the second case, where the counterion ion lies along the internuclear C═C axis, we find that K+ polarizes the electron density of the double bond more, resulting in a greater red shift than with Na+.
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Affiliation(s)
- Federico Coppola
- Department
of Chemical Sciences, University of Napoli
Federico II, Complesso Universitario di M.S. Angelo, 80126 Napoli, Italy
- Scuola
Superiore Meridionale, Largo San Marcellino 10, 80138 Napoli, Italy
| | - Paola Cimino
- Department
of Pharmaceutical Sciences, University of
Salerno, 84084 Fisciano, Italy
| | - Fulvio Perrella
- Department
of Chemical Sciences, University of Napoli
Federico II, Complesso Universitario di M.S. Angelo, 80126 Napoli, Italy
- Scuola
Superiore Meridionale, Largo San Marcellino 10, 80138 Napoli, Italy
| | - Luigi Crisci
- Department
of Chemical Sciences, University of Napoli
Federico II, Complesso Universitario di M.S. Angelo, 80126 Napoli, Italy
| | - Alessio Petrone
- Department
of Chemical Sciences, University of Napoli
Federico II, Complesso Universitario di M.S. Angelo, 80126 Napoli, Italy
- Scuola
Superiore Meridionale, Largo San Marcellino 10, 80138 Napoli, Italy
- Istituto
Nazionale di Fisica Nucleare, Sezione di Napoli, Complesso Universitario di Monte S. Angelo ed. 6, 80126 Napoli, Italy
| | - Nadia Rega
- Department
of Chemical Sciences, University of Napoli
Federico II, Complesso Universitario di M.S. Angelo, 80126 Napoli, Italy
- Scuola
Superiore Meridionale, Largo San Marcellino 10, 80138 Napoli, Italy
- Istituto
Nazionale di Fisica Nucleare, Sezione di Napoli, Complesso Universitario di Monte S. Angelo ed. 6, 80126 Napoli, Italy
- Centro
Interdipartimentale di Ricerca sui Biomateriali (CRIB), Piazzale Tecchio, 80125 Napoli, Italy
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4
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Sharma B, Tran VA, Pongratz T, Galazzo L, Zhurko I, Bordignon E, Kast SM, Neese F, Marx D. A Joint Venture of Ab Initio Molecular Dynamics, Coupled Cluster Electronic Structure Methods, and Liquid-State Theory to Compute Accurate Isotropic Hyperfine Constants of Nitroxide Probes in Water. J Chem Theory Comput 2021; 17:6366-6386. [PMID: 34516119 PMCID: PMC8515807 DOI: 10.1021/acs.jctc.1c00582] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 01/11/2023]
Abstract
The isotropic hyperfine coupling constant (HFCC, Aiso) of a pH-sensitive spin probe in a solution, HMI (2,2,3,4,5,5-hexamethylimidazolidin-1-oxyl, C9H19N2O) in water, is computed using an ensemble of state-of-the-art computational techniques and is gauged against X-band continuous wave electron paramagnetic resonance (EPR) measurement spectra at room temperature. Fundamentally, the investigation aims to delineate the cutting edge of current first-principles-based calculations of EPR parameters in aqueous solutions based on using rigorous statistical mechanics combined with correlated electronic structure techniques. In particular, the impact of solvation is described by exploiting fully atomistic, RISM integral equation, and implicit solvation approaches as offered by ab initio molecular dynamics (AIMD) of the periodic bulk solution (using the spin-polarized revPBE0-D3 hybrid functional), embedded cluster reference interaction site model integral equation theory (EC-RISM), and polarizable continuum embedding (using CPCM) of microsolvated complexes, respectively. HFCCs are obtained from efficient coupled cluster calculations (using open-shell DLPNO-CCSD theory) as well as from hybrid density functional theory (using revPBE0-D3). Re-solvation of "vertically desolvated" spin probe configuration snapshots by EC-RISM embedding is shown to provide significantly improved results compared to CPCM since only the former captures the inherent structural heterogeneity of the solvent close to the spin probe. The average values of the Aiso parameter obtained based on configurational statistics using explicit water within AIMD and from EC-RISM solvation are found to be satisfactorily close. Using either such explicit or RISM solvation in conjunction with DLPNO-CCSD calculations of the HFCCs provides an average Aiso parameter for HMI in aqueous solution at 300 K and 1 bar that is in good agreement with the experimentally determined one. The developed computational strategy is general in the sense that it can be readily applied to other spin probes of similar molecular complexity, to aqueous solutions beyond ambient conditions, as well as to other solvents in the longer run.
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Affiliation(s)
- Bikramjit Sharma
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Van Anh Tran
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Tim Pongratz
- Physikalische
Chemie III, Technische Universität
Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Laura Galazzo
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, 44780 Bochum, Germany
| | - Irina Zhurko
- Laboratory
of Nitrogen Compounds, N.N. Vorozhtsov Novosibirsk Institute of Organic
Chemistry, NIOCH SB RAS, 9 Lavrentiev Avenue, 630090, Novosibirsk, Russia
| | - Enrica Bordignon
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, 44780 Bochum, Germany
| | - Stefan M. Kast
- Physikalische
Chemie III, Technische Universität
Dortmund, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Dominik Marx
- Lehrstuhl
für Theoretische Chemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
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5
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Witwicki M, Lewińska A, Ozarowski A. o-Semiquinone radical anion isolated as an amorphous porous solid. Phys Chem Chem Phys 2021; 23:17408-17419. [PMID: 34351330 DOI: 10.1039/d1cp01596f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of metal cations is a commonly applied strategy to create S > 1/2 stable molecular systems containing semiquinone radicals. Persistent mono-semiquinonato complexes of diamagnetic metal ions (S = 1/2) have been hitherto less common and mostly limited to the complexes of heavy metal ions. In this work, a mono-semiquinonato complex of aluminum, derived from 1,2-dihydroxybenzene, is obtained using a surprisingly short and uncomplicated procedure. The isolated product is an amorphous and porous solid that exhibits very good stability under ambient conditions. To characterise its molecular and electronic structure, 9.7, 34 and 406 GHz EPR spectroscopy was used in concert with computational techniques (DFT and DLPNO-CCSD). It was revealed that the radical complex is composed of two chemically equivalent aluminum cations and two catechol-like ligands with the unpaired electron uniformly distributed between the two organic molecules. The good stability and porous structure make this complex applicable in heterogeneous aerobic reactions.
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Affiliation(s)
- Maciej Witwicki
- Faculty of Chemistry, Wroclaw University, Joliot-Curie 14, 50-383 Wroclaw, Poland.
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6
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Witwicki M, Walencik PK, Jezierska J. How accurate is density functional theory in predicting spin density? An insight from the prediction of hyperfine coupling constants. J Mol Model 2019; 26:10. [PMID: 31834497 DOI: 10.1007/s00894-019-4268-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/25/2019] [Indexed: 01/30/2023]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy has been proven to be an important technique for studying paramagnetic systems. Probably, the most accessible EPR parameter and the one that provides a significant amount of information about molecular structure and spin density is the hyperfine coupling constant (HFCC). Hence, accurate quantum-chemical modeling of HFCCs is frequently essential to the adequate interpretation of EPR spectra. It requires the precise spin density, which is the difference between the densities of α- and β-electrons, and thus, its quality is expected to reflect the quality of the total electron density. The question of which approximate exchange-correlation density functional yields sufficiently accurate HFCCs, and thus, the spin density remains open. To assess the performance of well-established density functionals for calculating HFCCs, we used a series of 26 small paramagnetic species and compared the obtained results to the CCSD reference values. The performance of DFT was also tested on EPR-studied o-semiquinone radical interacting with water molecules and Mg2+ cation. The HFCCs were additionally calculated by the DLPNO-CCSD method, and this wave function-based technique was found superior to all functionals we tested. Although some functionals were found, on average, to be fairly efficient, we found that the most accurate functional is system-dependent, and therefore, the DLPNO-CCSD method should be preferred for theoretical investigations of the HFCCs and spin density.
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Affiliation(s)
- Maciej Witwicki
- Faculty of Chemistry, Wrocław University, ul. F. Joliot-Curie 14, 50-383, Wrocław, Poland.
| | - Paulina K Walencik
- Faculty of Chemistry, Wrocław University, ul. F. Joliot-Curie 14, 50-383, Wrocław, Poland
| | - Julia Jezierska
- Faculty of Chemistry, Wrocław University, ul. F. Joliot-Curie 14, 50-383, Wrocław, Poland
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7
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Giovannini T, Lafiosca P, Chandramouli B, Barone V, Cappelli C. Effective yet reliable computation of hyperfine coupling constants in solution by a QM/MM approach: Interplay between electrostatics and non-electrostatic effects. J Chem Phys 2019; 150:124102. [DOI: 10.1063/1.5080810] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Piero Lafiosca
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Balasubramanian Chandramouli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
- Compunet, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy
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8
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Massolle A, Dresselhaus T, Eusterwiemann S, Doerenkamp C, Eckert H, Studer A, Neugebauer J. Towards reliable references for electron paramagnetic resonance parameters based on quantum chemistry: the case of verdazyl radicals. Phys Chem Chem Phys 2018; 20:7661-7675. [PMID: 29497710 DOI: 10.1039/c7cp05657e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present an efficient and accurate computational procedure to calculate properties measurable by EPR spectroscopy. We simulate a molecular dynamics (MD) trajectory by employing the quantum mechanically derived force field (QMDFF) [S. Grimme, J. Chem. Theory Comput., 2014, 10, 4497] and sample the trajectory at different time steps. For each snapshot EPR properties are calculated with a hybrid density functional theory (DFT) method. EPR spectra are simulated based on the averaged results. We applied the strategy to a number of previously published and novel verdazyl radicals, for which we recorded EPR spectra. The resulting simulated spectra are compatible with experiment already before employing an additional fitting step, in contrast to those from single point electronic-structure calculations. After the refinement, the experimental data are excellently reproduced, and the fitted EPR parameters do not deviate much from the calculated ones. This provides confidence in ascribing a direct physical meaning to the refined data in terms of experimental EPR parameters rather than merely considering them as mathematical fit parameters. We also find that couplings to hydrogen nuclei have a significant influence on the spectra of verdazyl radicals.
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Affiliation(s)
- Anja Massolle
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany.
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9
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Boulon M, Fernandez A, Moreno Pineda E, Chilton NF, Timco G, Fielding AJ, Winpenny REP. Measuring Spin⋅⋅⋅Spin Interactions between Heterospins in a Hybrid [2]Rotaxane. Angew Chem Int Ed Engl 2017; 56:3876-3879. [PMID: 28276620 PMCID: PMC5434811 DOI: 10.1002/anie.201612249] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Indexed: 12/29/2022]
Abstract
Use of molecular electron spins as qubits for quantum computing will depend on the ability to produce molecules with weak but measurable interactions between the qubits. Here we demonstrate use of pulsed EPR spectroscopy to measure the interaction between two inequivalent spins in a hybrid rotaxane molecule.
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Affiliation(s)
- Marie‐Emmanuelle Boulon
- The School of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Antonio Fernandez
- The School of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Eufemio Moreno Pineda
- The School of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Nicholas F. Chilton
- The School of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Grigore Timco
- The School of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Alistair J. Fielding
- The School of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Richard E. P. Winpenny
- The School of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
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10
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Boulon ME, Fernandez A, Moreno Pineda E, Chilton NF, Timco G, Fielding AJ, Winpenny REP. Measuring Spin⋅⋅⋅Spin Interactions between Heterospins in a Hybrid [2]Rotaxane. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612249] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Marie-Emmanuelle Boulon
- The School of Chemistry and Photon Science Institute; The University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Antonio Fernandez
- The School of Chemistry and Photon Science Institute; The University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Eufemio Moreno Pineda
- The School of Chemistry and Photon Science Institute; The University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Nicholas F. Chilton
- The School of Chemistry and Photon Science Institute; The University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Grigore Timco
- The School of Chemistry and Photon Science Institute; The University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Alistair J. Fielding
- The School of Chemistry and Photon Science Institute; The University of Manchester; Oxford Road Manchester M13 9PL UK
| | - Richard E. P. Winpenny
- The School of Chemistry and Photon Science Institute; The University of Manchester; Oxford Road Manchester M13 9PL UK
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11
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Sultani HN, Haeri HH, Hinderberger D, Westermann B. Spin-labelled diketopiperazines and peptide-peptoid chimera by Ugi-multi-component-reactions. Org Biomol Chem 2016; 14:11336-11341. [PMID: 27878155 DOI: 10.1039/c6ob02194h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For the first time, spin-labelled coumpounds have been obtained by isonitrile-based multi component reactions (IMCRs). The typical IMCR Ugi-protocols offer a simple experimental setup allowing structural variety by which labelled diketopiperazines (DKPs) and peptide-peptoid chimera have been synthesized. The reaction keeps the paramagnetic spin label intact and offers a simple and versatile route to a large variety of new and chemically diverse spin labels.
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Affiliation(s)
- Haider N Sultani
- Leibniz-Institute of Plant Biochemistry, Department of Bioorganic Chemistry, Weinberg 3, 06120 Halle, Germany.
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12
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Concilio MG, Fielding AJ, Bayliss R, Burgess SG. Density functional theory studies of MTSL nitroxide side chain conformations attached to an activation loop. Theor Chem Acc 2016; 135:97. [PMID: 27069413 PMCID: PMC4805727 DOI: 10.1007/s00214-016-1859-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 03/08/2016] [Indexed: 11/24/2022]
Abstract
A quantum mechanical (QM) method rooted on density functional theory (DFT) has been employed to determine conformations of the methane-thiosulfonate spin label (MTSL) attached to a fragment extracted from the activation loop of Aurora-A kinase. The features of the calculated energy surface revealed low energy barriers between isoenergetic minima, and the system could be described in a population of 76 rotamers that can be also considered for other systems since it was found that the \documentclass[12pt]{minimal}
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\begin{document}$$ \chi_{5} $$\end{document}χ5 do not depend on the previous two dihedral angles. Conformational states obtained were seen to be comparable to those obtained in the α-helix systems studied previously, indicating that the protein backbone does not affect the torsional profiles significantly and suggesting the possibility to use determined conformations for other protein systems for further modelling studies.
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Affiliation(s)
- Maria Grazia Concilio
- The Photon Science Institute and School of Chemistry, EPSRC National EPR Facility and Service, University of Manchester, Manchester, M13 9PY UK
| | - Alistair J Fielding
- The Photon Science Institute and School of Chemistry, EPSRC National EPR Facility and Service, University of Manchester, Manchester, M13 9PY UK
| | - Richard Bayliss
- Astbury Centre for Structural and Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT UK
| | - Selena G Burgess
- Astbury Centre for Structural and Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT UK
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13
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Küçük SE, Biktagirov T, Sezer D. Carbon and proton Overhauser DNP from MD simulations and ab initio calculations: TEMPOL in acetone. Phys Chem Chem Phys 2015; 17:24874-84. [PMID: 26343351 DOI: 10.1039/c5cp04405g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A computational analysis of the Overhauser effect is reported for the proton, methyl carbon, and carbonyl carbon nuclei of liquid acetone doped with the nitroxide radical TEMPOL. A practical methodology for calculating the dynamic nuclear polarization (DNP) coupling factors by accounting for both dipole-dipole and Fermi-contact interactions is presented. The contribution to the dipolar spectral density function of nuclear spins that are not too far from TEMPOL is computed through classical molecular dynamics (MD) simulations, whereas the contribution of distant spins is included analytically. Fermi contacts are obtained by subjecting a few molecules from every MD snapshot to ab initio quantum mechanical calculations. Scalar interaction is found to be an essential part of the (13)C Overhauser DNP. While mostly detrimental to the carbonyl carbon of acetone it is predicted to result in large enhancements of the methyl carbon signal at magnetic fields of 9 T and beyond. In contrast, scalar coupling is shown to be negligible for the protons of acetone. The additional influence of proton polarization on the carbon DNP (three-spin effect) is also analyzed computationally. Its effect, however, is concluded to be practically insignificant for liquid acetone.
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Affiliation(s)
- Sami Emre Küçük
- Faculty of Engineering and Natural Sciences, Sabanc University, Orhanl-Tuzla, 34956 Istanbul, Turkey.
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14
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Gast P, Herbonnet RTL, Klare J, Nalepa A, Rickert C, Stellinga D, Urban L, Möbius K, Savitsky A, Steinhoff HJ, Groenen EJJ. Hydrogen bonding of nitroxide spin labels in membrane proteins. Phys Chem Chem Phys 2014; 16:15910-6. [DOI: 10.1039/c4cp01741b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
On the basis of experiments at 275 GHz, we reconsider the dependence of the continuous-wave EPR spectra of nitroxide spin-labeled protein sites in sensory- and bacteriorhodopsin on the micro-environment.
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Affiliation(s)
- P. Gast
- Huygens-Kamerlingh Onnes Laboratory
- Department of Physics
- Leiden University
- NL-2300 RA Leiden, The Netherlands
| | - R. T. L. Herbonnet
- Huygens-Kamerlingh Onnes Laboratory
- Department of Physics
- Leiden University
- NL-2300 RA Leiden, The Netherlands
| | - J. Klare
- Department of Physics
- University of Osnabrück
- D-49076 Osnabrück, Germany
| | - A. Nalepa
- Max Planck Institute for Chemical Energy Conversion
- D-45470 Mülheim an der Ruhr, Germany
| | - C. Rickert
- Department of Physics
- University of Osnabrück
- D-49076 Osnabrück, Germany
| | - D. Stellinga
- Huygens-Kamerlingh Onnes Laboratory
- Department of Physics
- Leiden University
- NL-2300 RA Leiden, The Netherlands
| | - L. Urban
- Department of Physics
- University of Osnabrück
- D-49076 Osnabrück, Germany
| | - K. Möbius
- Max Planck Institute for Chemical Energy Conversion
- D-45470 Mülheim an der Ruhr, Germany
- Department of Physics
- Free University Berlin
- D-14195 Berlin, Germany
| | - A. Savitsky
- Max Planck Institute for Chemical Energy Conversion
- D-45470 Mülheim an der Ruhr, Germany
| | - H.-J. Steinhoff
- Department of Physics
- University of Osnabrück
- D-49076 Osnabrück, Germany
| | - E. J. J. Groenen
- Huygens-Kamerlingh Onnes Laboratory
- Department of Physics
- Leiden University
- NL-2300 RA Leiden, The Netherlands
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15
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Schmidt TC, Paasche A, Grebner C, Ansorg K, Becker J, Lee W, Engels B. QM/MM investigations of organic chemistry oriented questions. Top Curr Chem (Cham) 2014; 351:25-101. [PMID: 22392477 DOI: 10.1007/128_2011_309] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
About 35 years after its first suggestion, QM/MM became the standard theoretical approach to investigate enzymatic structures and processes. The success is due to the ability of QM/MM to provide an accurate atomistic picture of enzymes and related processes. This picture can even be turned into a movie if nuclei-dynamics is taken into account to describe enzymatic processes. In the field of organic chemistry, QM/MM methods are used to a much lesser extent although almost all relevant processes happen in condensed matter or are influenced by complicated interactions between substrate and catalyst. There is less importance for theoretical organic chemistry since the influence of nonpolar solvents is rather weak and the effect of polar solvents can often be accurately described by continuum approaches. Catalytic processes (homogeneous and heterogeneous) can often be reduced to truncated model systems, which are so small that pure quantum-mechanical approaches can be employed. However, since QM/MM becomes more and more efficient due to the success in software and hardware developments, it is more and more used in theoretical organic chemistry to study effects which result from the molecular nature of the environment. It is shown by many examples discussed in this review that the influence can be tremendous, even for nonpolar reactions. The importance of environmental effects in theoretical spectroscopy was already known. Due to its benefits, QM/MM can be expected to experience ongoing growth for the next decade.In the present chapter we give an overview of QM/MM developments and their importance in theoretical organic chemistry, and review applications which give impressions of the possibilities and the importance of the relevant effects. Since there is already a bunch of excellent reviews dealing with QM/MM, we will discuss fundamental ingredients and developments of QM/MM very briefly with a focus on very recent progress. For the applications we follow a similar strategy.
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Affiliation(s)
- Thomas C Schmidt
- Institut für Phys. und Theor. Chemie, Emil-Fischer-Strasse 42, Campus Hubland Nord, 97074, Würzburg, Germany
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16
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Elgabarty H, Wolff M, Glaubitz A, Hinderberger D, Sebastiani D. First principles calculation of inhomogeneous broadening in solid-state cw-EPR spectroscopy. Phys Chem Chem Phys 2013; 15:16082-9. [PMID: 23985880 DOI: 10.1039/c3cp51938d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We present a scheme for the first-principles calculation of EPR lineshapes for continuous-wave-EPR spectroscopy (cw-EPR) of spin centers in complex chemical environments. We specifically focus on poorly characterized systems, e.g. powders and frozen glasses with variable microsolvation structures. Our approach is based on ab initio molecular dynamics simulations and ab initio calculations of the ensemble of g- and A-tensors along the trajectory. The method incorporates temperature effects as well as the full anharmonicity of the intra- and intermolecular degrees of freedom of the system. We apply this scheme to compute the lineshape of a prototypical spin probe, the nitrosodisulfonate dianionic radical (Fremy's salt), dissolved in a 50 : 50 mixture of water and methanol. We are able to determine the specific effect of variations of local solvent composition and microsolvation structure on the cw-EPR lineshape. Our molecular dynamics reveal a highly anisotropic solvation structure with distinct spatial preferences for water and methanol around Fremy's salt that can be traced back to a combination of steric and polar influences. The overall solvation structure and conformational preferences of Fremy's salt as found in our MD simulations agree very well with the results obtained from EPR and orientation-selective ENDOR spectroscopy performed on the frozen glass. The simulated EPR lineshapes show good agreement with the experimental spectra. When combined with our MD results, they characterize the lineshape dependence on local morphological fluctuations.
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Affiliation(s)
- Hossam Elgabarty
- Dahlem Center for Complex Quantum Systems (DCCQS), Physics Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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17
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Hermosilla L, Prampolini G, Calle P, García de la Vega JM, Brancato G, Barone V. Extension of the AMBER Force Field for Nitroxide Radicals and Combined QM/MM/PCM Approach to the Accurate Determination of EPR Parameters of DMPO-H in Solution. J Chem Theory Comput 2013; 9:3626-36. [PMID: 26584116 PMCID: PMC4660035 DOI: 10.1021/ct4003256] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A computational strategy that combines both time-dependent and time-independent approaches is exploited to accurately model molecular dynamics and solvent effects on the isotropic hyperfine coupling constants of the DMPO-H nitroxide. Our recent general force field for nitroxides derived from AMBER ff99SB is further extended to systems involving hydrogen atoms in β-positions with respect to NO-moiety. The resulting force-field has been employed in a series of classical molecular dynamics simulations, comparing the computed EPR parameters from selected molecular configurations to the corresponding experimental data in different solvents. The effect of vibrational averaging on the spectroscopic parameters is also taken into account, by second-order vibrational perturbation theory involving semidiagonal third energy derivatives together first and second property derivatives.
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Affiliation(s)
- Laura Hermosilla
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid (Spain)
| | - Giacomo Prampolini
- Istituto per i Processi Chimico-Fisici, Consiglio Nazionale delle Ricerche, Area della Ricerca, via Moruzzi 1, I-56124, Pisa (Italy)
| | - Paloma Calle
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid (Spain)
| | | | - Giuseppe Brancato
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126, Pisa (Italy)
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126, Pisa (Italy)
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18
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19
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Frecus B, Rinkevicius Z, Ågren H. π-Stacking effects on the EPR parameters of a prototypical DNA spin label. Phys Chem Chem Phys 2013; 15:10466-71. [PMID: 23685812 DOI: 10.1039/c3cp51129d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The character and value of spin labels for probing environments like double-stranded DNA depend on the degree of change in the spin Hamiltonian parameters of the spin label induced by the environment. Herein we provide a systematic theoretical investigation of this issue, based on a density functional theory method applied to a spin labeled DNA model system, focusing on the dependence of the EPR properties of the spin label on the π stacking and hydrogen bonding that occur upon incorporating the spin label into the selected base pair inside DNA. It is found that the EPR spin Hamiltonian parameters of the spin label are only negligibly affected by its incorporation into DNA, when compared to its free form. This result gives a theoretical ground for the common empirical assumption regarding the behaviour of spin Hamiltonian parameters made in EPR based measurements of the distance between spin labels incorporated into DNA.
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Affiliation(s)
- Bogdan Frecus
- KTH Royal Institute of Technology, School of Biotechnology, Division of Theoretical Chemistry & Biology, SE-106 91 Stockholm, Sweden.
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20
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Egidi F, Bloino J, Cappelli C, Barone V, Tomasi J. Tuning of NMR and EPR parameters by vibrational averaging and environmental effects: an integrated computational approach. Mol Phys 2013. [DOI: 10.1080/00268976.2013.796413] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Franco Egidi
- a Scuola Normale Superiore , Piazza dei Cavalieri , Pisa , Italy
| | - Julien Bloino
- a Scuola Normale Superiore , Piazza dei Cavalieri , Pisa , Italy
- b CNR, Consiglio Nazionale delle Ricerche , Istituto di Chimica dei Composti Organometallici , UOS di Pisa, Via G. Moruzzi, Pisa , Italy
| | - Chiara Cappelli
- a Scuola Normale Superiore , Piazza dei Cavalieri , Pisa , Italy
- c Dipartimento di Chimica e Chimica Industriale , Università di Pisa , via Risorgimento, Pisa , Italy
| | - Vincenzo Barone
- a Scuola Normale Superiore , Piazza dei Cavalieri , Pisa , Italy
| | - Jacopo Tomasi
- c Dipartimento di Chimica e Chimica Industriale , Università di Pisa , via Risorgimento, Pisa , Italy
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21
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Frecus B, Rinkevicius Z, Murugan NA, Vahtras O, Kongsted J, Ågren H. EPR spin Hamiltonian parameters of encapsulated spin-labels: impact of the hydrogen bonding topology. Phys Chem Chem Phys 2013; 15:2427-34. [DOI: 10.1039/c2cp43951d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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22
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Collauto A, Barbon A, Brustolon M. First determination of the spin relaxation properties of a nitronyl nitroxide in solution by electron spin echoes at X-band: a comparison with Tempone. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 223:180-186. [PMID: 22975247 DOI: 10.1016/j.jmr.2012.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 07/12/2012] [Accepted: 07/13/2012] [Indexed: 06/01/2023]
Abstract
We studied by electron spin echo pulse methods the spin relaxation properties of a phenyl nitronyl nitroxide radical (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide, PTIO) at X-band in fluid toluene solution in a wide temperature range, and in a water/glycerol 1:1 mixture near room temperature. The relaxation properties of PTIO have been compared with that of Tempone, as a widely used nitroxide. By a new procedure, based on experimental results on the temperature dependences of the relaxation times T(1) and T(2), and on the approximation of an isotropic brownian rotational diffusion, we separated non-secular, spin rotational and residual terms from the transverse relaxation rate to isolate secular and pseudosecular contributions. By comparing the results for the two radicals we found the differences in the magnetic properties that give rise to slower transverse (T(2)) and longitudinal (T(1)) electron spin relaxation for PTIO in the whole temperature range explored in this work.
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Affiliation(s)
- A Collauto
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, I-35131 Padova, Italy
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23
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Caruso P, Causà M, Cimino P, Crescenzi O, D’Amore M, Improta R, Pavone M, Rega N. Effects of molecular dynamics and solvation on the electronic structure of molecular probes. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1211-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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24
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Bernini C, Pogni R, Basosi R, Sinicropi A. The nature of tryptophan radicals involved in the long-range electron transfer of lignin peroxidase and lignin peroxidase-like systems: Insights from quantum mechanical/molecular mechanics simulations. Proteins 2012; 80:1476-83. [DOI: 10.1002/prot.24046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 01/18/2012] [Accepted: 01/25/2012] [Indexed: 01/21/2023]
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25
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Rinkevicius Z, Frecuş B, Murugan NA, Vahtras O, Kongsted J, Ågren H. Encapsulation Influence on EPR Parameters of Spin-Labels: 2,2,6,6-Tetramethyl-4-methoxypiperidine-1-oxyl in Cucurbit[8]uril. J Chem Theory Comput 2011; 8:257-63. [DOI: 10.1021/ct200816z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Zilvinas Rinkevicius
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
- Swedish e-Science Research Center (SeRC), Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Bogdan Frecuş
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - N. Arul Murugan
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Olav Vahtras
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Hans Ågren
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
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26
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Rinkevicius Z, Murugan NA, Kongsted J, Frecuş B, Steindal AH, Ågren H. Density Functional Restricted–Unrestricted/Molecular Mechanics Theory for Hyperfine Coupling Constants of Molecules in Solution. J Chem Theory Comput 2011; 7:3261-71. [DOI: 10.1021/ct2003572] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zilvinas Rinkevicius
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
- Swedish e-Science Research Center (SeRC), Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - N. Arul Murugan
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Jacob Kongsted
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Bogdan Frecuş
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Arnfinn Hykkerud Steindal
- Centre of Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway
| | - Hans Ågren
- Department of Theoretical Chemistry & Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
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27
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Rinkevicius Z, Murugan NA, Kongsted J, Aidas K, Steindal AH, Ågren H. Density Functional Theory/Molecular Mechanics Approach for Electronic g-Tensors of Solvated Molecules. J Phys Chem B 2011; 115:4350-8. [DOI: 10.1021/jp1108653] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Zilvinas Rinkevicius
- Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
- Swedish e-Science Research Center (SeRC), Royal Institute of Technology, 10044 Stockholm, Sweden
| | - N. Arul Murugan
- Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Jacob Kongsted
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Kęstutis Aidas
- Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - Arnfinn Hykkerud Steindal
- Centre of Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway
| | - Hans Ågren
- Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
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28
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Puzzarini C, Barone V. Toward spectroscopic accuracy for open-shell systems: molecular structure and hyperfine coupling constants of H2CN, H2CP, NH2, and PH2 as test cases. J Chem Phys 2011; 133:184301. [PMID: 21073217 DOI: 10.1063/1.3503763] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the present paper, we investigate the molecular structure and hyperfine couplings of a series of σ radicals containing first- and second-row atoms (H(2)CN,H(2)CP,NH(2),PH(2)) for which accurate gas-phase microwave results are available. The presence of α- and, especially, β-hydrogen atoms makes the evaluation of magnetic properties of these radicals particularly challenging. Geometrical parameters have been computed by the coupled-cluster ansatz in conjunction with hierarchical series of basis sets, thus accounting for extrapolation to the complete basis-set limit. Core correlation as well as higher excitations in the electronic-correlation treatment have also been taken into account. An analogous approach has been employed for evaluating hyperfine coupling constants with particular emphasis given to basis-set, correlation, and geometrical effects. The corresponding vibrational corrections, required for a meaningful comparison to experimental data, have also been investigated. The remarkable agreement with experiment confirms the reliability of the present computational approach, already validated for π radicals, thus establishing the way for setting up a benchmark database for magnetic properties.
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica G. Ciamician, Università di Bologna, Via F. Selmi 2, 40126 Bologna, Italy.
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29
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Oganesyan VS. A general approach for prediction of motional EPR spectra from Molecular Dynamics (MD) simulations: application to spin labelled protein. Phys Chem Chem Phys 2011; 13:4724-37. [PMID: 21279205 DOI: 10.1039/c0cp01068e] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A general approach for the prediction of EPR spectra directly and completely from single dynamical trajectories generated from Molecular Dynamics (MD) simulations is described. The approach is applicable to an arbitrary system of electron and nuclear spins described by a general form of the spin-Hamiltonian for the entire motional range. It is shown that for a reliable simulation of motional EPR spectra only a single truncated dynamical trajectory generated until the point when correlation functions of rotational dynamics are completely relaxed is required. The simulation algorithm is based on a combination of the propagation of the spin density matrix in the Liouville space for this initial time interval and the use of well defined parameters calculated entirely from the dynamical trajectory for prediction of the evolution of the spin density matrix at longer times. A new approach is illustrated with the application to a nitroxide spin label MTSL attached to the protein sperm whale myoglobin. It is shown that simulation of the EPR spectrum, which is in excellent agreement with experiment, can be achieved from a single MD trajectory. Calculations reveal the complex nature of the dynamics of a spin label which is a superposition of the fast librational motions within dihedral states, of slow rotameric dynamics among different conformational states of the nitroxide tether and of the slow rotational diffusion of the protein itself. The significance of the slow rotameric dynamics of the nitroxide tether on the overall shape of the EPR spectrum is analysed and discussed.
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30
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Bernini C, Pogni R, Ruiz-Dueñas FJ, Martínez AT, Basosi R, Sinicropi A. EPR parameters of amino acid radicals in P. eryngii versatile peroxidase and its W164Y variant computed at the QM/MM level. Phys Chem Chem Phys 2011; 13:5078-98. [DOI: 10.1039/c0cp02151b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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31
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Hermosilla L, Vega JMGDL, Sieiro C, Calle P. DFT Calculations of Isotropic Hyperfine Coupling Constants of Nitrogen Aromatic Radicals: The Challenge of Nitroxide Radicals. J Chem Theory Comput 2010; 7:169-79. [PMID: 26606230 DOI: 10.1021/ct1006136] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The performance of DFT methodology to predict with accuracy the isotropic hyperfine coupling constants (hfccs) of aromatic radicals containing (14)N nucleus is investigated by an extensive study in which 165 hfccs, belonging to 38 radical species, are obtained from calculations with B3LYP and PBE0 functionals combined with 6-31G*, N07D, TZVP, and EPR-III basis sets, and are compared to the reported experimental data. The results indicate that the selection of the basis set is of fundamental importance in the calculation of (14)N hfccs, whereas there is not so great an influence on the accurate computation of that parameter for (1)H nuclei. The values of the calculated (14)N coupling constants of aromatic nitroxide radicals using DFT methodology are noticeably lower than the experimental ones. A very simple relation to predict these hfccs with high accuracy is proposed on the basis of the present results, as an interesting alternative to the highly computationally demanding integrated approaches so far used.
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Affiliation(s)
- L Hermosilla
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - J M García de la Vega
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - C Sieiro
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - P Calle
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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32
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Houriez C, Masella M, Ferré N. Structural and atoms-in-molecules analysis of hydrogen-bond network around nitroxides in liquid water. J Chem Phys 2010; 133:124508. [DOI: 10.1063/1.3478999] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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33
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Pedone A, Biczysko M, Barone V. Environmental effects in computational spectroscopy: accuracy and interpretation. Chemphyschem 2010; 11:1812-32. [PMID: 20358575 DOI: 10.1002/cphc.200900976] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Spectroscopic techniques are valuable tools for understanding the structure and dynamics of complex systems, such as biomolecules or nanomaterials. Most of the current research is devoted to the development of new experimental techniques for improving the intrinsic resolution of different spectra. However, the subtle interplay of several different effects acting at different length and time scales still makes the interpretation and analysis of such spectra a very difficult task. In this respect, computational spectroscopy is becoming a needful and versatile tool for the assignment and interpretation of experimental spectra. It is in fact possible nowadays to model with relatively high accuracy the physical-chemical properties of complex molecules in different environments, and to link spectroscopic evidence directly to the structural and dynamical properties of optically or magnetically active solvated probes. In this Review, significant steps toward the simulation of entire spectra in condensed phases are presented together with some basic aspects of computational spectroscopy, which highlight how intramolecular and intermolecular degrees of freedom influence several spectroscopic parameters.
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Affiliation(s)
- Alfonso Pedone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa, Italy
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Frolov AE, Sviryaeva IV, Ruuge EK, Trubitsin BV, Tikhonov AN. EPR spectra of the trimethyl-1,4-benzoquinone anion-radical: Results of calculations by the density functional method and their comparison with experiment. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2010. [DOI: 10.1134/s0036024410090189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Houriez C, Ferré N, Siri D, Tordo P, Masella M. Structure and Spectromagnetic Properties of the Superoxide Radical Adduct of DMPO in Water: Elucidation by Theoretical Investigations. J Phys Chem B 2010; 114:11793-803. [DOI: 10.1021/jp1033307] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Céline Houriez
- UMR 6264 Laboratoire Chimie Provence, Faculté des Sciences de Saint-Jérome Case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France, and Laboratoire de Chimie du Vivant, Service d’ingénierie moléculaire des protéines, Institut de biologie et de technologies de Saclay, Commissariat a l’énergie atomique, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Nicolas Ferré
- UMR 6264 Laboratoire Chimie Provence, Faculté des Sciences de Saint-Jérome Case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France, and Laboratoire de Chimie du Vivant, Service d’ingénierie moléculaire des protéines, Institut de biologie et de technologies de Saclay, Commissariat a l’énergie atomique, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Didier Siri
- UMR 6264 Laboratoire Chimie Provence, Faculté des Sciences de Saint-Jérome Case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France, and Laboratoire de Chimie du Vivant, Service d’ingénierie moléculaire des protéines, Institut de biologie et de technologies de Saclay, Commissariat a l’énergie atomique, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Paul Tordo
- UMR 6264 Laboratoire Chimie Provence, Faculté des Sciences de Saint-Jérome Case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France, and Laboratoire de Chimie du Vivant, Service d’ingénierie moléculaire des protéines, Institut de biologie et de technologies de Saclay, Commissariat a l’énergie atomique, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Michel Masella
- UMR 6264 Laboratoire Chimie Provence, Faculté des Sciences de Saint-Jérome Case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France, and Laboratoire de Chimie du Vivant, Service d’ingénierie moléculaire des protéines, Institut de biologie et de technologies de Saclay, Commissariat a l’énergie atomique, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
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Pavone M, Biczysko M, Rega N, Barone V. Magnetic Properties of Nitroxide Spin Probes: Reliable Account of Molecular Motions and Nonspecific Solvent Effects by Time-Dependent and Time-Independent Approaches. J Phys Chem B 2010; 114:11509-14. [DOI: 10.1021/jp102232c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Michele Pavone
- Department of Chemistry “P. Corradini”, University of Napoli Federico II and CR-INSTM “Village”, Complesso Universitario Monte Sant’Angelo, Via Cintia 80126, Napoli, Italy; and Scuola Normale Superiore di Pisa, and INFN Sezione di Pisa, Piazza dei Cavalieri 7, I-56126, Pisa, Italy
| | - Malgorzata Biczysko
- Department of Chemistry “P. Corradini”, University of Napoli Federico II and CR-INSTM “Village”, Complesso Universitario Monte Sant’Angelo, Via Cintia 80126, Napoli, Italy; and Scuola Normale Superiore di Pisa, and INFN Sezione di Pisa, Piazza dei Cavalieri 7, I-56126, Pisa, Italy
| | - Nadia Rega
- Department of Chemistry “P. Corradini”, University of Napoli Federico II and CR-INSTM “Village”, Complesso Universitario Monte Sant’Angelo, Via Cintia 80126, Napoli, Italy; and Scuola Normale Superiore di Pisa, and INFN Sezione di Pisa, Piazza dei Cavalieri 7, I-56126, Pisa, Italy
| | - Vincenzo Barone
- Department of Chemistry “P. Corradini”, University of Napoli Federico II and CR-INSTM “Village”, Complesso Universitario Monte Sant’Angelo, Via Cintia 80126, Napoli, Italy; and Scuola Normale Superiore di Pisa, and INFN Sezione di Pisa, Piazza dei Cavalieri 7, I-56126, Pisa, Italy
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Ikryannikova LN, Ustynyuk LY, Tikhonov AN. DFT study of nitroxide radicals: explicit modeling of solvent effects on the structural and electronic characteristics of 4-amino-2,2,6,6-tetramethyl-piperidine-N-oxyl. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2010; 48:337-349. [PMID: 20225189 DOI: 10.1002/mrc.2585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An explicit DFT modeling of water surroundings on the electron paramagnetic resonance properties of 4-amino-2,2,6,6-tetramethyl-piperidine-N-oxyl (TA) has been performed. A stepwise hydration of TA is accompanied with certain changes in geometrical parameters (bond lengths and angles) and redistribution of partial electric charges in TA. An aqueous cluster of 45 water molecules can be considered as an appropriate model for a complete aqueous shell around TA, although most of the structural and electronic characteristics of TA already converge at about 10 water molecules. Water surroundings induce an increase in electron spin density on the nitrogen atom of the nitroxide fragment due to stabilization of the polar resonance structure > N(+*)-O(-) at the expense of less polar structure > N-O*. The water-induced rise of the isotropic splitting constant a(iso), calculated from the contact term of the hyperfine interaction, comprises Deltaa(iso)(rho(N2)) = 2.2-2.5 G, which is typical of experimental value for TA. There are two contributions to the solvent effect on the a(iso)(rho(N2)) value: the redistribution of spin density in the nitroxide fragment (polarity effect) and water-induced distortions of TA geometry. Microscopic variations in a hydrogen-bonded water network cause noticeable fluctuations of the splitting constant a(iso)(rho(N2)). Calculations of the atomic spin density (sigma(N2)) allowed us to compute the splitting constant from the relationship a(iso)(sigma(N2)) = Qsigma(N2), where Q = 36.2 G. A practical advantage of using this relationship is that it gives 'smoothed' values of the splitting constant, which are sensitive to the environment polarity but remain tolerant to microscopic fluctuations of the hydrogen-bonded water network around a spin-label molecule.
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Stendardo E, Pedone A, Cimino P, Cristina Menziani M, Crescenzi O, Barone V. Extension of the AMBER force-field for the study of large nitroxides in condensed phases: an ab initio parameterization. Phys Chem Chem Phys 2010; 12:11697-709. [DOI: 10.1039/c001481h] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Houriez C, Ferré N, Siri D, Masella M. Further Insights into the Environmental Effects on the Computed Hyperfine Coupling Constants of Nitroxides in Aqueous Solution. J Phys Chem B 2009; 113:15047-56. [DOI: 10.1021/jp906828v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Céline Houriez
- UMR 6264 Laboratoire Chimie Provence, Faculté des Sciences de Saint-Jérôme Case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France, UMR 8000 Laboratoire de Chimie Physique, Université Paris-Sud 11, 91405 Orsay Cedex, France, and Laboratoire de Chimie du Vivant, Service d’ingénierie moléculaire des protéines, Institut de biologie et de technologies de Saclay, Commissariat à l’énergie atomique, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Nicolas Ferré
- UMR 6264 Laboratoire Chimie Provence, Faculté des Sciences de Saint-Jérôme Case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France, UMR 8000 Laboratoire de Chimie Physique, Université Paris-Sud 11, 91405 Orsay Cedex, France, and Laboratoire de Chimie du Vivant, Service d’ingénierie moléculaire des protéines, Institut de biologie et de technologies de Saclay, Commissariat à l’énergie atomique, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Didier Siri
- UMR 6264 Laboratoire Chimie Provence, Faculté des Sciences de Saint-Jérôme Case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France, UMR 8000 Laboratoire de Chimie Physique, Université Paris-Sud 11, 91405 Orsay Cedex, France, and Laboratoire de Chimie du Vivant, Service d’ingénierie moléculaire des protéines, Institut de biologie et de technologies de Saclay, Commissariat à l’énergie atomique, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Michel Masella
- UMR 6264 Laboratoire Chimie Provence, Faculté des Sciences de Saint-Jérôme Case 521, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France, UMR 8000 Laboratoire de Chimie Physique, Université Paris-Sud 11, 91405 Orsay Cedex, France, and Laboratoire de Chimie du Vivant, Service d’ingénierie moléculaire des protéines, Institut de biologie et de technologies de Saclay, Commissariat à l’énergie atomique, Centre de Saclay, 91191 Gif-sur-Yvette Cedex, France
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Armstrong BD, Soto P, Shea JE, Han S. Overhauser dynamic nuclear polarization and molecular dynamics simulations using pyrroline and piperidine ring nitroxide radicals. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 200:137-141. [PMID: 19535275 DOI: 10.1016/j.jmr.2009.05.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2009] [Revised: 05/25/2009] [Accepted: 05/28/2009] [Indexed: 05/27/2023]
Abstract
The efficiency of Overhauser dynamic nuclear polarization (DNP) depends on the local dynamics modulating the dipolar coupling between the two interacting spins. By attaching nitroxide based spin labels to molecules and by measuring the (1)H DNP response of solvent water, information about the local hydration dynamics near the spin label can be obtained. However, there are two commonly used types of nitroxide ring structures; a pyrroline based and a piperidine based molecule. It is important to know when comparing different experiments, whether changes in DNP enhancements are due to changes in local hydration dynamics or because of the different spin label structures. In this study we investigate the key parameters affecting DNP signal enhancements for 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-1-oxyl, a 5-membered ring nitroxide radical, and for 4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy, a 6-membered ring nitroxide radical. Using X-Band DNP, field cycling relaxometry, and molecular dynamics simulations, we conclude that the key parameters affecting the DNP amplitude of the (1)H signal of water to be equal when using either nitroxide. Thus, experiments measuring hydration dynamics using either type of spin labels may be compared.
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Affiliation(s)
- Brandon D Armstrong
- Department of Physics, University of California, Santa Barbara, CA 93106, USA
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Sezer D, Prandolini MJ, Prisner TF. Dynamic nuclear polarization coupling factors calculated from molecular dynamics simulations of a nitroxide radical in water. Phys Chem Chem Phys 2009; 11:6626-37. [PMID: 19639137 DOI: 10.1039/b905709a] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magnetic resonance signal obtained from nuclear spins is strongly affected by the presence of nearby electronic spins. This effect finds application in biomedical imaging and structural characterization of large biomolecules. In many of these applications nitroxide free radicals are widely used due to their non-toxicity and versatility as site-specific spin labels. We perform molecular dynamics simulations to study the electron-nucleus interaction of the nitroxide radical TEMPOL and water in atomistic detail. Correlation functions corresponding to the dipolar and scalar spin-spin couplings are computed from the simulations. The dynamic nuclear polarization coupling factors deduced from these correlation functions are in good agreement with experiment over a broad range of magnetic field strengths. The present approach can be applied to study solute-solvent interactions in general, and to characterize solvent dynamics on the surfaces of proteins or other spin-labeled biomolecules in particular.
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Affiliation(s)
- Deniz Sezer
- Institut für Physikalische und Theoretische Chemie, J. W. Goethe-Universität, 60438 Frankfurt am Main, Germany
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Houriez C, Ferré N, Masella M, Siri D. Quantitative evaluation of the aqueous dihydronitroxide nitrogen hyperfine coupling constant from QM/MM//MD computations. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.theochem.2008.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mattar SM, Sanford J. Role of the Geometry, Restricted Rotations and Solvents on the Computed 2,2′-Diphenyl-1-picrylhydrazyl Hyperfine Tensors. J Phys Chem A 2008; 112:11349-54. [DOI: 10.1021/jp806919k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Saba M. Mattar
- Department of Chemistry and Centre for Laser, Atomic and Molecular Sciences, University of New Brunswick, Fredericton, NB, Canada E3B 6E2
| | - Jacob Sanford
- Department of Chemistry and Centre for Laser, Atomic and Molecular Sciences, University of New Brunswick, Fredericton, NB, Canada E3B 6E2
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Savitsky A, Dubinskii AA, Plato M, Grishin YA, Zimmermann H, Möbius K. High-Field EPR and ESEEM Investigation of the Nitrogen Quadrupole Interaction of Nitroxide Spin Labels in Disordered Solids: Toward Differentiation between Polarity and Proticity Matrix Effects on Protein Function. J Phys Chem B 2008; 112:9079-90. [DOI: 10.1021/jp711640p] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Savitsky
- Department of Physics, Free University Berlin, Arnimallee 14, D-14195 Berlin, Germany, Semenov Institute of Chemical Physics, Kosygina str. 4, 119991 Moscow, Russia, Institute of Chemical Kinetics and Combustion, Institutskaya str. 3, 630090 Novosibirsk, Russia, and Max-Planck-Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - A. A. Dubinskii
- Department of Physics, Free University Berlin, Arnimallee 14, D-14195 Berlin, Germany, Semenov Institute of Chemical Physics, Kosygina str. 4, 119991 Moscow, Russia, Institute of Chemical Kinetics and Combustion, Institutskaya str. 3, 630090 Novosibirsk, Russia, and Max-Planck-Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - M. Plato
- Department of Physics, Free University Berlin, Arnimallee 14, D-14195 Berlin, Germany, Semenov Institute of Chemical Physics, Kosygina str. 4, 119991 Moscow, Russia, Institute of Chemical Kinetics and Combustion, Institutskaya str. 3, 630090 Novosibirsk, Russia, and Max-Planck-Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - Y. A. Grishin
- Department of Physics, Free University Berlin, Arnimallee 14, D-14195 Berlin, Germany, Semenov Institute of Chemical Physics, Kosygina str. 4, 119991 Moscow, Russia, Institute of Chemical Kinetics and Combustion, Institutskaya str. 3, 630090 Novosibirsk, Russia, and Max-Planck-Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - H. Zimmermann
- Department of Physics, Free University Berlin, Arnimallee 14, D-14195 Berlin, Germany, Semenov Institute of Chemical Physics, Kosygina str. 4, 119991 Moscow, Russia, Institute of Chemical Kinetics and Combustion, Institutskaya str. 3, 630090 Novosibirsk, Russia, and Max-Planck-Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - K. Möbius
- Department of Physics, Free University Berlin, Arnimallee 14, D-14195 Berlin, Germany, Semenov Institute of Chemical Physics, Kosygina str. 4, 119991 Moscow, Russia, Institute of Chemical Kinetics and Combustion, Institutskaya str. 3, 630090 Novosibirsk, Russia, and Max-Planck-Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
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Houriez C, Ferré N, Masella M, Siri D. Prediction of nitroxide hyperfine coupling constants in solution from combined nanosecond scale simulations and quantum computations. J Chem Phys 2008; 128:244504. [DOI: 10.1063/1.2939121] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Barone V, Causà M. Structure and ESR features of a radiation-induced radical in α-glycine crystals. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2007.12.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Asher JR, Kaupp M. Car-Parrinello molecular dynamics simulations and EPR property calculations on aqueous ubisemiquinone radical anion. Theor Chem Acc 2008. [DOI: 10.1007/s00214-007-0408-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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