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Probing Small-Angle Molecular Motions with EPR Spectroscopy: Dynamical Transition and Molecular Packing in Disordered Solids. MAGNETOCHEMISTRY 2022. [DOI: 10.3390/magnetochemistry8020019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Disordered molecular solids present a rather broad class of substances of different origin—amorphous polymers, materials for photonics and optoelectronics, amorphous pharmaceutics, simple molecular glass formers, and others. Frozen biological media in many respects also may be referred to this class. Theoretical description of dynamics and structure of disordered solids still does not exist, and only some phenomenological models can be developed to explain results of particular experiments. Among different experimental approaches, electron paramagnetic resonance (EPR) applied to spin probes and labels also can deliver useful information. EPR allows probing small-angle orientational molecular motions (molecular librations), which intrinsically are inherent to all molecular solids. EPR is employed in its conventional continuous wave (CW) and pulsed—electron spin echo (ESE)—versions. CW EPR spectra are sensitive to dynamical librations of molecules while ESE probes stochastic molecular librations. In this review, different manifestations of small-angle motions in EPR of spin probes and labels are discussed. It is shown that CW-EPR-detected dynamical librations provide information on dynamical transition in these media, similar to that explored with neutron scattering, and ESE-detected stochastic librations allow elucidating some features of nanoscale molecular packing. The possible EPR applications are analyzed for gel-phase lipid bilayers, for biological membranes interacting with proteins, peptides and cryoprotectants, for supercooled ionic liquids (ILs) and supercooled deep eutectic solvents (DESs), for globular proteins and intrinsically disordered proteins (IDPs), and for some other molecular solids.
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Zanatta M, Tavagnacco L, Buratti E, Bertoldo M, Natali F, Chiessi E, Orecchini A, Zaccarelli E. Evidence of a low-temperature dynamical transition in concentrated microgels. SCIENCE ADVANCES 2018; 4:eaat5895. [PMID: 30276264 PMCID: PMC6162076 DOI: 10.1126/sciadv.aat5895] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 08/21/2018] [Indexed: 05/07/2023]
Abstract
A low-temperature dynamical transition has been reported in several proteins. We provide the first observation of a "protein-like" dynamical transition in nonbiological aqueous environments. To this aim, we exploit the popular colloidal system of poly-N-isopropylacrylamide (PNIPAM) microgels, extending their investigation to unprecedentedly high concentrations. Owing to the heterogeneous architecture of the microgels, water crystallization is avoided in concentrated samples, allowing us to monitor atomic dynamics at low temperatures. By elastic incoherent neutron scattering and molecular dynamics simulations, we find that a dynamical transition occurs at a temperature T d ~ 250 K, independently from PNIPAM mass fraction. However, the transition is smeared out on approaching dry conditions. The quantitative agreement between experiments and simulations provides evidence that the transition occurs simultaneously for PNIPAM and water dynamics. The similarity of these results with hydrated protein powders suggests that the dynamical transition is a generic feature in complex macromolecular systems, independently from their biological function.
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Affiliation(s)
- Marco Zanatta
- Department of Computer Science, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Letizia Tavagnacco
- Consiglio Nazionale delle Ricerche (CNR)–Istituto dei Sistemi Complessi, Sede Sapienza, and Department of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
| | - Elena Buratti
- CNR–Istituto per i Processi Chimico-Fisici, Sede Secondaria di Pisa, Area della Ricerca, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Monica Bertoldo
- CNR–Istituto per i Processi Chimico-Fisici, Sede Secondaria di Pisa, Area della Ricerca, via G. Moruzzi 1, 56124 Pisa, Italy
- Corresponding author. (M.B.); (A.O.); (E.Z.)
| | - Francesca Natali
- CNR–Istituto Officina dei Materiali (IOM), Operative Group in Grenoble, c/o Institut Laue Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France
| | - Ester Chiessi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133 Rome, Italy
| | - Andrea Orecchini
- Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia, Italy
- CNR-IOM c/o Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia, Italy
- Corresponding author. (M.B.); (A.O.); (E.Z.)
| | - Emanuela Zaccarelli
- Consiglio Nazionale delle Ricerche (CNR)–Istituto dei Sistemi Complessi, Sede Sapienza, and Department of Physics, Sapienza University of Rome, Piazzale A. Moro 2, 00185 Rome, Italy
- Corresponding author. (M.B.); (A.O.); (E.Z.)
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Golysheva EA, Shevelev GY, Dzuba SA. Dynamical transition in molecular glasses and proteins observed by spin relaxation of nitroxide spin probes and labels. J Chem Phys 2018; 147:064501. [PMID: 28810753 DOI: 10.1063/1.4997035] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In glassy substances and biological media, dynamical transitions are observed in neutron scattering that manifests itself as deviations of the translational mean-squared displacement, 〈x2〉, of hydrogen atoms from harmonic dynamics. In biological media, the deviation occurs at two temperature intervals, at ∼100-150 K and at ∼170-230 K, and it is attributed to the motion of methyl groups in the former case and to the transition from harmonic to anharmonic or diffusive motions in the latter case. In this work, electron spin echo (ESE) spectroscopy-a pulsed version of electron paramagnetic resonance-is applied to study the spin relaxation of nitroxide spin probes and labels introduced in molecular glass former o-terphenyl and in protein lysozyme. The anisotropic contribution to the rate of the two-pulse ESE decay, ΔW, is induced by spin relaxation appearing because of restricted orientational stochastic molecular motion; it is proportional to 〈α2〉τc, where 〈α2〉 is the mean-squared angle of reorientation of the nitroxide molecule around the equilibrium position and τc is the correlation time of reorientation. The ESE time window allows us to study motions with τc < 10-7 s. For glassy o-terphenyl, the 〈α2〉τc temperature dependence shows a transition near 240 K, which is in agreement with the literature data on 〈x2〉. For spin probes of essentially different size, the obtained data were found to be close, which evidences that motion is cooperative, involving a nanocluster of several neighboring molecules. For the dry lysozyme, the 〈α2〉τc values below 260 K were found to linearly depend on the temperature in the same way as it was observed in neutron scattering for 〈x2〉. As spin relaxation is influenced only by stochastic motion, the harmonic motions seen in ESE must be overdamped. In the hydrated lysozyme, ESE data show transitions near 130 K for all nitroxides, near 160 K for the probe located in the hydration layer, and near 180 K for the label in the protein interior. For this system, the two latter transitions are not observed in neutron scattering. The ESE-detected transitions are suggested to be related with water dynamics in the nearest hydration shell: with water glass transition near 130 K and with the onset of overall water molecular reorientations near 180 K; the disagreement with neutron scattering is ascribed to the larger time window for ESE-detected motions.
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Affiliation(s)
- Elena A Golysheva
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
| | - Georgiy Yu Shevelev
- Department of Physics, Novosibirsk State University, Novosibirsk 630090, Russian Federation
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
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Mamontov E. Microscopic diffusion in hydrated encysted eggs of brine shrimp. Biochim Biophys Acta Gen Subj 2017; 1861:2382-2390. [PMID: 28549919 DOI: 10.1016/j.bbagen.2017.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 05/07/2017] [Accepted: 05/23/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND We have studied microscopic diffusion of water in fully hydrated encysted eggs of brine shrimp (Artemia). METHODS We have utilized quasielastic neutron scattering. RESULTS Dry eggs of brine shrimp were rehydrated using (1) water without additives, (2) eutectic mixture of water and dimethyl sulfoxide, and (3) a concentrated aqueous solution of lithium chloride. Despite the complexity of the hydrated multicellular organism, measurable microscopic diffusivity of water is rather well defined. Pure hydration water in eggs exhibits freezing temperature depression, whereas hydration water in eggs mixed with dimethyl sulfoxide or lithium chloride does not crystallize at all. CONCLUSIONS The characteristic size of the voids occupied by water or aqueous solvents in hydrated brine shrimp eggs is between 2 and 10nm. Those voids are accessible to co-solvents such as dimethyl sulfoxide and lithium chloride. There is no evidence of intracellular water in the hydrated eggs. GENERAL SIGNIFICANCE The lack of intracellular water in the fully hydrated (but still under arrested development) state must be linked to the unique resilience against adverse environmental factors documented not only for the anhydrous, but also hydrated encysted eggs of brine shrimp.
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Affiliation(s)
- E Mamontov
- Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
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Frontzek (neé Svanidze) AV, Embs JP, Paccou L, Guinet Y, Hédoux A. Low-Frequency Dynamics of BSA Complementarily Studied by Raman and Inelastic Neutron Spectroscopy. J Phys Chem B 2017; 121:5125-5132. [DOI: 10.1021/acs.jpcb.7b01395] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anna V. Frontzek (neé Svanidze)
- Jülich
Center for Neutron Science (JCNS), Forschungszentrum Jülich GmbH, Outstation
at MLZ, Lichtenbergstraße 1, 85747 Garching, Germany
- A.F. Ioffe Physical Technical Institute, ul. Politekhnicheskaya 26, 194021 St. Petersburg, Russian Federation
| | - Jan Peter Embs
- Laboratory
for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | | | - Yannick Guinet
- Université Lille Nord de France, F-59000 Lille, France
- USTL UMET UMR CNRS 8207, F-59655 Villeneuve d’Ascq, France
| | - Alain Hédoux
- Université Lille Nord de France, F-59000 Lille, France
- USTL UMET UMR CNRS 8207, F-59655 Villeneuve d’Ascq, France
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Syryamina VN, Dzuba SA. Dynamical Transitions at Low Temperatures in the Nearest Hydration Shell of Phospholipid Bilayers. J Phys Chem B 2017; 121:1026-1032. [DOI: 10.1021/acs.jpcb.6b10133] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- V. N. Syryamina
- Institute
of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
- Physics
Department, Novosibirsk State University, Novosibirsk 630090, Russian Federation
| | - S. A. Dzuba
- Institute
of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
- Physics
Department, Novosibirsk State University, Novosibirsk 630090, Russian Federation
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Mamontov E. A novel approach to neutron scattering instrumentation for probing multiscale dynamics in soft and biological matter. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:345201. [PMID: 27355223 DOI: 10.1088/0953-8984/28/34/345201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a concept and ray-tracing simulation of a mechanical device that will enable inelastic neutron scattering measurements where the data at energy transfers from a few μeV to several hundred meV can be collected in a single, gapless spectrum. Besides covering 5 orders of magnitude on the energy (time) scale, the device provides data over 2 orders of magnitude on the scattering momentum (length) scale in a single measurement. Such capabilities are geared primarily toward soft and biological matter, where the broad dynamical features of relaxation origin largely overlap with vibration features, thus necessitating gapless spectral coverage over several orders of magnitude in time and space. Furthermore, neutron scattering experiments with such a device are performed with a fixed neutron final energy, which enables measurements, with neutron energy loss in the sample, at arbitrarily low temperatures over the same broad spectral range. This capability is also invaluable in biological and soft matter research, as the variable temperature dependence of different relaxation components allows their separation in the scattering spectra as a function of temperature.
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Affiliation(s)
- Eugene Mamontov
- Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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Mamontov E, O'Neill H. Microscopic relaxations in a protein sustained down to 160K in a non-glass forming organic solvent. Biochim Biophys Acta Gen Subj 2016; 1861:3513-3519. [PMID: 27154287 DOI: 10.1016/j.bbagen.2016.04.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/24/2016] [Accepted: 04/25/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND We have studied microscopic dynamics of a protein in carbon disulfide, a non-glass forming solvent, down to its freezing temperature of ca. 160K. METHODS We have utilized quasielastic neutron scattering. RESULTS A comparison of lysozyme hydrated with water and dissolved in carbon disulfide reveals a stark difference in the temperature dependence of the protein's microscopic relaxation dynamics induced by the solvent. In the case of hydration water, the common protein glass-forming solvent, the protein relaxation slows down in response to a large increase in the water viscosity on cooling down, exhibiting a well-known protein dynamical transition. The dynamical transition disappears in non-glass forming carbon disulfide, whose viscosity remains a weak function of temperature all the way down to freezing at just below 160K. The microscopic relaxation dynamics of lysozyme dissolved in carbon disulfide is sustained down to the freezing temperature of its solvent at a rate similar to that measured at ambient temperature. CONCLUSIONS Our results demonstrate that protein dynamical transition is not merely solvent-assisted, but rather solvent-induced, or, more precisely, is a reflection of the temperature dependence of the solvent's glass-forming dynamics. GENERAL SIGNIFICANCE We hypothesize that, if the long debated idea regarding the direct link between the microscopic relaxations and the biological activity in proteins is correct, then not only the microscopic relaxations, but also the activity, could be sustained in proteins all the way down to the freezing temperature of a non-glass forming solvent with a weak temperature dependence of its viscosity. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.
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Affiliation(s)
- E Mamontov
- Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
| | - H O'Neill
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States
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