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Liu TH, Okuno M. TMAO perturbs intermolecular vibrational motions of water revealed by low-frequency modes. Phys Chem Chem Phys 2024; 26:12397-12405. [PMID: 38619910 DOI: 10.1039/d4cp01025f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Trimethylamine N-oxide (TMAO) as a representative natural osmolyte has received much attention because of its unique properties, including enhancement of hydrogen bonding networks in liquid water and stabilization of three-dimensional structures of proteins in living organisms. As a hydrogen bond maker and/or a protein stabilizer, its hydrated structures and orientation dynamics in aqueous solutions have been investigated by various spectroscopic methods. Particularly, distinct from other natural osmolytes, it has been found that TMAO molecules form complexes with water molecules even at low concentrations, showing extraordinarily long lifetimes and much larger effective dipole moments. In this study, we demonstrated that collective motions of water molecules are closely correlated to TMAO molecules, as revealed by the changes of the librational modes observed in hyper-Raman (HR) spectra in the low-frequency region (<1000 cm-1) for the first time. Based on HR spectra of the TMAO solutions at submolar concentrations, we observed that the librational bands originating from water apparently upshift (∼15 cm-1) upon the addition of TMAO molecules. Compared to the OH stretching band of water showing a negligible downshift (<5 cm-1), the librational bands of water are more sensitive to reflect changes in the hydrogen bonding networks in the TMAO solutions, suggesting formation of transient TMAO-water complexes plays an essential role toward surrounding water molecules in perturbing their librational motions. We expect to provide a supplementary approach to understand that water molecules in TMAO aqueous solutions are strongly affected by TMAO molecules, different from other osmolytes.
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Affiliation(s)
- Tsung-Han Liu
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan.
| | - Masanari Okuno
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan.
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Feng Z, Ding W, Lin Y, Guo F, Zhang X, Song T, Li H, Liu C. Electron momentum density of boron-doped carbon nano-onions studied by electron energy-loss spectroscopy. Phys Chem Chem Phys 2021; 23:26343-26348. [PMID: 34788775 DOI: 10.1039/d1cp04334j] [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
Valence Compton profiles (CPs) (electron momentum density projections) of B-doped carbon nano-onions (CNOs) as a function of the boron doping content were obtained by recording electron energy-loss spectra at large scattering angles using a transmission electron microscope, a technique known as electron Compton scattering from solids (ECOSS). The amplitude of the CPs at zero momentum increases with increasing doping content, while the shape of the CPs becomes narrower with increasing doping content. The differences between the profiles of B-doped CNOs and that of pristine CNOs have been clearly observed. These experimental results indicate substantially greater delocalization of the ground-state charge density in B-doped CNOs than in pristine CNOs. The results clearly demonstrate that the ECOSS technique is an efficient and reliable experimental method for studying electron density distributions in solids as a function of the heteroatom doping content.
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Affiliation(s)
- Zhenbao Feng
- School of Physics Science and Information Technology, Shandong Key Laboratory of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China.
| | - Wei Ding
- School of Physics Science and Information Technology, Shandong Key Laboratory of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China.
| | - Yangming Lin
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China. .,Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institute, Chinese Academy of Sciences, Xiamen 361021, China
| | - Feng Guo
- School of Physics Science and Information Technology, Shandong Key Laboratory of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China.
| | - Xiaoyan Zhang
- Shandong Key Laboratory of Laser Polarization and Information Technology, College of Physics and Engineering, Qufu Normal University, Qufu 273163, P. R. China
| | - Tengshuo Song
- School of Physics Science and Information Technology, Shandong Key Laboratory of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China.
| | - Hengshuai Li
- School of Physics Science and Information Technology, Shandong Key Laboratory of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China.
| | - Cailong Liu
- School of Physics Science and Information Technology, Shandong Key Laboratory of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China.
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Frenzel L, Lokteva I, Koof M, Narayanan S, Grübel G, Lehmkühler F. Influence of TMAO as co-solvent on the gelation of silica-PNIPAm core-shell nanogels at intermediate volume fractions. Chemphyschem 2020; 21:1318-1325. [PMID: 32250508 PMCID: PMC7318175 DOI: 10.1002/cphc.202000114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/20/2020] [Indexed: 12/29/2022]
Abstract
We study the structure and dynamics of poly(N-isopropylacrylamide) (PNIPAm) core-shell nanogels dispersed in aqueous trimethylamine N-oxide (TMAO) solutions by means of small-angle X-ray scattering and X-ray photon correlation spectroscopy (XPCS). Upon increasing the temperature above the lower critical solution temperature of PNIPAm at 33 °C, a colloidal gel is formed as identified by an increase of I(q) at small q as well as a slowing down of sample dynamics by various orders of magnitude. With increasing TMAO concentration the gelation transition shifts linearly to lower temperatures. Above a TMAO concentration of approximately 0.40 mol/L corresponding to a 1 : 1 ratio of TMAO and NIPAm groups, collapsed PNIPAm states are found for all temperatures without any gelation transition. This suggests that reduction of PNIPAm-water hydrogen bonds due to the presence of TMAO results in a stabilisation of the collapsed PNIPAm state and suppresses gelation of the nanogel.
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Affiliation(s)
- Lara Frenzel
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Irina Lokteva
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Michael Koof
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Suresh Narayanan
- Advanced Photon SourceArgonne National LaboratoryArgonneIllinois60439United States
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESYNotkestr. 8522607HamburgGermany
- The Hamburg Centre for Ultrafast ImagingLuruper Chaussee 14922761HamburgGermany
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Sahle CJ, Schroer MA, Niskanen J, Elbers M, Jeffries CM, Sternemann C. Hydration in aqueous osmolyte solutions: the case of TMAO and urea. Phys Chem Chem Phys 2020; 22:11614-11624. [DOI: 10.1039/c9cp06785j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
X-ray Raman scattering spectroscopy and first principles simulations reveal details of the hydration and hydrogen-bond topology of trimethylamine N-oxide (TMAO) and urea in aqueous solutions.
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Affiliation(s)
| | - Martin A. Schroer
- European Molecular Biology Laboratory (EMBL)
- Hamburg Outstation c/o DESY
- Hamburg 22607
- Germany
| | - Johannes Niskanen
- Department of Physics and Astronomy
- University of Turku
- FI-20014 Turun Yliopisto
- Finland
| | - Mirko Elbers
- Fakultät Physik/DELTA
- Technische Universität Dortmund
- 44221 Dortmund
- Germany
| | - Cy M. Jeffries
- European Molecular Biology Laboratory (EMBL)
- Hamburg Outstation c/o DESY
- Hamburg 22607
- Germany
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Knierbein M, Held C, Hölzl C, Horinek D, Paulus M, Sadowski G, Sternemann C, Nase J. Density variations of TMAO solutions in the kilobar range: Experiments, PC-SAFT predictions, and molecular dynamics simulations. Biophys Chem 2019; 253:106222. [PMID: 31421516 DOI: 10.1016/j.bpc.2019.106222] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/10/2019] [Accepted: 07/10/2019] [Indexed: 01/12/2023]
Abstract
We present measurements, molecular dynamics (MD) simulations, and predictions using Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) of the density of aqueous solutions in a pressure range from 1 bar to 5000 bar, a pressure regime that is highly relevant for both biochemical applications and the fundamental understanding of solvation. The accurate determination of density data of pressurized solutions remains challenging. We determined relative density changes from the variations in X-ray absorption through the sample and developed a new water parameter set for PC-SAFT modeling that is appropriate for high pressure conditions in the kilobar regime. As a showcase, we studied trimethylamine N-oxide (TMAO) solutions and demonstrated that their compressibility decreases with the TMAO content. This result is linked to the stabilizing effect of TMAO on the local H-bond network of water. Experiments and calculations, which represent two independent methods, are in very good agreement and are in accordance with results of force field molecular dynamics simulations of the same systems.
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Affiliation(s)
- Michael Knierbein
- Technische Universität Dortmund, Laboratory of Thermodynamics, D-44221 Dortmund, Germany
| | - Christoph Held
- Technische Universität Dortmund, Laboratory of Thermodynamics, D-44221 Dortmund, Germany
| | - Christoph Hölzl
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
| | - Dominik Horinek
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
| | - Michael Paulus
- Technische Universität Dortmund, Fakultät Physik/DELTA, D-44221 Dortmund, Germany
| | - Gabriele Sadowski
- Technische Universität Dortmund, Laboratory of Thermodynamics, D-44221 Dortmund, Germany
| | - Christian Sternemann
- Technische Universität Dortmund, Fakultät Physik/DELTA, D-44221 Dortmund, Germany
| | - Julia Nase
- Technische Universität Dortmund, Fakultät Physik/DELTA, D-44221 Dortmund, Germany.
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Sahputra IH, Alexiadis A, Adams MJ. Effects of Moisture on the Mechanical Properties of Microcrystalline Cellulose and the Mobility of the Water Molecules as Studied by the Hybrid Molecular Mechanics-Molecular Dynamics Simulation Method. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/polb.24801] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Iwan H. Sahputra
- School of Chemical Engineering; University of Birmingham; Birmingham United Kingdom
| | - Alessio Alexiadis
- School of Chemical Engineering; University of Birmingham; Birmingham United Kingdom
| | - Michael J. Adams
- School of Chemical Engineering; University of Birmingham; Birmingham United Kingdom
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