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Maji D, Biswas R. Dielectric relaxation and dielectric decrement in ionic acetamide deep eutectic solvents: Spectral decomposition and comparison with experiments. J Chem Phys 2023; 158:2888209. [PMID: 37139998 DOI: 10.1063/5.0147378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/17/2023] [Indexed: 05/05/2023] Open
Abstract
Frequency-dependent dielectric relaxation in three deep eutectic solvents (DESs), (acetamide+LiClO4/NO3/Br), was investigated in the temperature range, 329 ≤ T/K ≤ 358, via molecular dynamics simulations. Subsequently, decomposition of the real and the imaginary components of the simulated dielectric spectra was carried out to separate the rotational (dipole-dipole), translational (ion-ion), and ro-translational (dipole-ion) contributions. The dipolar contribution, as expected, was found to dominate all the frequency-dependent dielectric spectra over the entire frequency regime, while the other two components together made tiny contributions only. The translational (ion-ion) and the cross ro-translational contributions appeared in the THz regime in contrast to the viscosity-dependent dipolar relaxations that dominated the MHz-GHz frequency window. Our simulations predicted, in agreement with experiments, anion-dependent decrement of the static dielectric constant (ɛs ∼ 20 to 30) for acetamide (ɛs ∼ 66) in these ionic DESs. Simulated dipole-correlations (Kirkwood g factor) indicated significant orientational frustrations. The frustrated orientational structure was found to be associated with the anion-dependent damage of the acetamide H-bond network. Single dipole reorientation time distributions suggested slowed down acetamide rotations but did not indicate presence of any "rotationally frozen" molecule. The dielectric decrement is, therefore, largely static in origin. This provides a new insight into the ion dependence of the dielectric behavior of these ionic DESs. A good agreement between the simulated and the experimental timescales was also noticed.
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Affiliation(s)
- Dhrubajyoti Maji
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector III, Salt Lake, Kolkata, West Bengal 700106, India
| | - Ranjit Biswas
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector III, Salt Lake, Kolkata, West Bengal 700106, India
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2
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Honegger P, Steinhauser O, Schröder C. Collective Spectroscopy of Solvation Phenomena: Conflicts, Challenges, and Opportunities. J Phys Chem Lett 2023; 14:609-618. [PMID: 36634000 DOI: 10.1021/acs.jpclett.2c03574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Different spectroscopy types reveal different aspects of molecular processes in soft matter. In particular, collective observables can provide insights into intermolecular correlations invisible to the more popular single-particle methods. In this perspective we feature the dielectric relaxation spectroscopy (DRS) with an emphasis on the proper interpretation of this complex observable aided by computational spectroscopy. While we focus on the history and recent advances of DRS in the fields of biomolecular hydration and nanoconfinement, the discussion transcends this particular field and provides a guide for how collective spectroscopy types supported by computational decomposition can be employed to further our understanding of soft matter phenomena.
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Affiliation(s)
- Philipp Honegger
- University of Vienna,Faculty of Chemistry, Department of Computational Biological Chemistry, Wien, 1090, Austria
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, BostonMassachusetts02115, United States
| | - Othmar Steinhauser
- University of Vienna,Faculty of Chemistry, Department of Computational Biological Chemistry, Wien, 1090, Austria
| | - Christian Schröder
- University of Vienna,Faculty of Chemistry, Department of Computational Biological Chemistry, Wien, 1090, Austria
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3
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Zhang J, Yan Y, Wang B, Liu L, Li S, Tian Z, Ouyang C, Gu J, Zhang X, Chen Y, Han J, Zhang W. Water dynamics in the hydration shell of hyper-branched poly-ethylenimine. Phys Chem Chem Phys 2022; 24:18393-18400. [PMID: 35880732 DOI: 10.1039/d2cp01944b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We performed THz and GHz dielectric relaxation spectroscopy to investigate the reorientational dynamics of water molecules in the hydration shell of amphiphilic hyper-branched poly-ethylenimine (HPEI). Four Debye equations were employed to describe four types of water in the hydration shell, including bulk-like water, under-coordinated water, slow water (water molecules hydrating the hydrophobic groups and water molecules accepting hydrogen bonds from the NH2 groups) and super slow water (water molecules donating hydrogen bonds to and accepting hydrogen bonds from NH groups). The time scales of undercoordinated and bulk-like water show a slight decline from 0.4 to 0.1 ps and from 8 to 2 ps, respectively. Because of hydrophilic amino groups, HPEI molecules exhibit a strong retardation effect, where the time scales of slow and super slow water increase with concentration from 17 to 39.9 ps and from 88 to 225 ps, respectively.
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Affiliation(s)
- Jiaqi Zhang
- Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, People's Republic of China.
| | - Yuyue Yan
- Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, People's Republic of China.
| | - Bin Wang
- Tianjin Engineering Technology Center of Chemical Wastewater Source Reduction and Recycling, School of Science, Tianjin Chengjian University, Tianjin 300072, People's Republic of China
| | - Liyuan Liu
- Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, People's Republic of China.
| | - Shaoxian Li
- Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, People's Republic of China.
| | - Zhen Tian
- Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, People's Republic of China.
| | - Chunmei Ouyang
- Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, People's Republic of China.
| | - Jianqiang Gu
- Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, People's Republic of China.
| | - Xueqian Zhang
- Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, People's Republic of China.
| | - Yu Chen
- Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Sciences, Tianjin University, Tianjin 300354, China
| | - Jiaguang Han
- Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tinajin 300072, People's Republic of China.
| | - Weili Zhang
- School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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Honegger P, Steinhauser O. The nuclear Overhauser Effect (NOE) as a tool to study macromolecular confinement: Elucidation and disentangling of crowding and encapsulation effects. J Chem Phys 2020; 152:024120. [PMID: 31941328 DOI: 10.1063/1.5135816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We propose a methodology to capture short-lived but biophysically important contacts of biomacromolecules using the biomolecule-water nuclear Overhauser effect as an indirect microscope. Thus, instead of probing the direct correlation with the foreign biomolecule, we detect its presence by the disturbance it causes in the surrounding water. In addition, this information obtained is spatially resolved and can thus be attributed to specific sites. We extend this approach to the influence of more than one change in chemical environment and show a methodological way of resolution. This is achieved by taking double differences of corresponding σNOE/σROE ratios of the systems studied and separating specific, unspecific, and intermediate influence. While applied to crowding and encapsulation in this study, this method is generally suitable for any combination of changes in chemical environment.
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Affiliation(s)
- Philipp Honegger
- University of Vienna, Faculty of Chemistry, Department of Computational Biological Chemistry, Währingerstraße 17, A-1090 Vienna, Austria
| | - Othmar Steinhauser
- University of Vienna, Faculty of Chemistry, Department of Computational Biological Chemistry, Währingerstraße 17, A-1090 Vienna, Austria
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5
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Honegger P, Heid E, Schröder C, Steinhauser O. Dielectric spectroscopy and time dependent Stokes shift: two faces of the same coin? Phys Chem Chem Phys 2020; 22:18388-18399. [DOI: 10.1039/d0cp02840a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Different types of spectroscopy capture different aspects of dynamics and different ranges of intermolecular contributions.
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Affiliation(s)
- Philipp Honegger
- University of Vienna
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- 1090 Vienna
- Austria
| | - Esther Heid
- University of Vienna
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- 1090 Vienna
- Austria
| | - Christian Schröder
- University of Vienna
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- 1090 Vienna
- Austria
| | - Othmar Steinhauser
- University of Vienna
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- 1090 Vienna
- Austria
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6
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Honegger P, Steinhauser O. The protein-water nuclear Overhauser effect (NOE) as an indirect microscope for molecular surface mapping of interaction patterns. Phys Chem Chem Phys 2019; 22:212-222. [PMID: 31799520 DOI: 10.1039/c9cp04752b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In this computational study, the intermolecular solute-solvent Nuclear Overhauser Effect (NOE) of the model protein ubiquitin in different chemical environments (free, bound to a partner protein and encapsulated) is investigated. Short-ranged NOE observables such as the NOE/ROE ratio reveal hydration phenomena on absolute timescales such as fast hydration sites and slow water clefts. We demonstrate the ability of solute-solvent NOE differences measured of the same protein in different chemical environments to reveal hydration changes on the relative timescale. The resulting NOE/ROE-surface maps are shown to be a central key for analyzing biologically relevant chemical influences such as complexation and confinement: the presence of a complexing macromolecule or a confining surface wall modulates the water mobility in the vicinity of the probe protein, hence revealing which residues of said protein are proximate to the foreign interface and which are chemically unaffected. This way, hydration phenomena can serve to indirectly map the precise influence (position) of other molecules or interfaces onto the protein surface. This proposed one-protein many-solvents approach may offer experimental benefits over classical one-protein other-protein pseudo-intermolecular transient NOEs. Furthermore, combined influences such as complexation and confinement may exert non-additive influences on the protein compared to a reference state. We offer a mathematical method to disentangle the influence of these two different chemical environments.
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Affiliation(s)
- Philipp Honegger
- University of Vienna, Faculty of Chemistry, Department of Computational Biological Chemistry, Währingerstr. 17, A-1090 Vienna, Austria.
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7
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Honegger P, Steinhauser O. Hydration dynamics of proteins in reverse micelles probed by 1H-NOESY/ 1H-ROESY NMR and 17O-nuclear quadrupole resonance (NQR). Phys Chem Chem Phys 2019; 21:14571-14582. [PMID: 31237595 DOI: 10.1039/c9cp02654a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study is based on extensive MD simulations of a protein in a reverse micelle to mimic the effect of confinement on biomolecules. This permits the calculation of measurable quantities appearing in NQR and Nuclear Overhauser-NMR despite the high computational effort. We address the long-standing debate about the intermolecular NOE showing that absolute quantities derived from NOESY and ROESY spectra do indeed contain considerable long-range contributions, while ratios thereof are effectively short-ranged due to almost perfect compensation effects. Based on NQR relaxation times, we predict strong rotational retardation of interstitial water between the protein and the surfactant surface. The computed NOE to ROE ratio correlates fairly with experimental results. The solvation dynamics mapped onto the protein surface reflects the spatial heterogeneity of a cell-like system with slow water dynamics in proximity to the cell wall and almost bulk-like behaviour in the water core.
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Affiliation(s)
- Philipp Honegger
- University of Vienna, Faculty of Chemistry, Department of Computational Biological Chemistry, Währingerstr. 17, A-1090 Vienna, Austria.
| | - Othmar Steinhauser
- University of Vienna, Faculty of Chemistry, Department of Computational Biological Chemistry, Währingerstr. 17, A-1090 Vienna, Austria.
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Honegger P, Steinhauser O. Towards capturing cellular complexity: combining encapsulation and macromolecular crowding in a reverse micelle. Phys Chem Chem Phys 2019; 21:8108-8120. [DOI: 10.1039/c9cp00053d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper studies the orientational structure and dynamics of multi-protein systems under confinement and discusses the implications on biological cells.
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Affiliation(s)
- Philipp Honegger
- University of Vienna
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- A-1090 Vienna
- Austria
| | - Othmar Steinhauser
- University of Vienna
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- A-1090 Vienna
- Austria
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9
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Senske M, Xu Y, Bäumer A, Schäfer S, Wirtz H, Savolainen J, Weingärtner H, Havenith M. Local chemistry of the surfactant's head groups determines protein stability in reverse micelles. Phys Chem Chem Phys 2018. [DOI: 10.1039/c8cp00407b] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Protein stability in reverse micelles is determined by local chemical interactions between the surfactant molecules and the protein groups.
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Affiliation(s)
- Michael Senske
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Yao Xu
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Alexander Bäumer
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Sarah Schäfer
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Hanna Wirtz
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Janne Savolainen
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Hermann Weingärtner
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
| | - Martina Havenith
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
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Honegger P, Schmollngruber M, Steinhauser O. Micellar confinement disrupts collective structure and accelerates collective dynamics of encapsulated water. Phys Chem Chem Phys 2018; 20:11454-11469. [DOI: 10.1039/c8cp01508b] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Detailed numerical study of the dielectric spectrum of zwitterionic reverse micelles is combined with interpretation using a new semi-quantitative analytical model.
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Affiliation(s)
- Philipp Honegger
- University of Vienna
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- A-1090 Vienna
- Austria
| | - Michael Schmollngruber
- University of Vienna
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- A-1090 Vienna
- Austria
| | - Othmar Steinhauser
- University of Vienna
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- A-1090 Vienna
- Austria
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11
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Honegger P, Steinhauser O. Revival of collective water structure and dynamics in reverse micelles brought about by protein encapsulation. Phys Chem Chem Phys 2018; 20:22932-22945. [DOI: 10.1039/c8cp03422b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel mechanism of depolarization in reverse micelles with zwitterionic surfactants and containing polar species but lacking ions is reported.
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Affiliation(s)
- Philipp Honegger
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- University of Vienna
- A-1090 Vienna
- Austria
| | - Othmar Steinhauser
- Faculty of Chemistry
- Department of Computational Biological Chemistry
- University of Vienna
- A-1090 Vienna
- Austria
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