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Pastorczak M, Duk K, Shahab S, Kananenka AA. Combinational Vibration Modes in H 2O/HDO/D 2O Mixtures Detected Thanks to the Superior Sensitivity of Femtosecond Stimulated Raman Scattering. J Phys Chem B 2023. [PMID: 37201478 DOI: 10.1021/acs.jpcb.3c01334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Overtones and combinational modes frequently play essential roles in ultrafast vibrational energy relaxation in liquid water. However, these modes are very weak and often overlap with fundamental modes, particularly in isotopologues mixtures. We measured VV and HV Raman spectra of H2O and D2O mixtures with femtosecond stimulated Raman scattering (FSRS) and compared the results with calculated spectra. Specifically, we observed the mode at around 1850 cm-1 and assigned it to H-O-D bend + rocking libration. Second, we found that the H-O-D bend overtone band and the OD stretch + rocking libration combination band contribute to the band located between 2850 and 3050 cm-1. Furthermore, we assigned the broad band located between 4000 and 4200 cm-1 to be composed of combinational modes of high-frequency OH stretching modes with predominantly twisting and rocking librations. These results should help in a proper interpretation of Raman spectra of aqueous systems as well as in the identification of vibrational relaxation pathways in isotopically diluted water.
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Affiliation(s)
- Marcin Pastorczak
- Institute of Physical Chemistry, Polish Academy of Sciences, Laser Centre, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Katsiaryna Duk
- Institute of Physical Chemistry, Polish Academy of Sciences, Laser Centre, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Samaneh Shahab
- Institute of Physical Chemistry, Polish Academy of Sciences, Laser Centre, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Alexei A Kananenka
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, United States
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2
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Li ZJ, Srebnik S, Rojas OJ. Competing Effects of Hydration and Cation Complexation in Single-Chain Alginate. Biomacromolecules 2022; 23:1949-1957. [PMID: 35362969 DOI: 10.1021/acs.biomac.1c01591] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Alginic acid, a naturally occurring anionic polyelectrolyte, forms strong physically cross-linked hydrogels in the presence of metal cations. The latter engage in electrostatic interactions that compete with intra- and intermolecular hydrogen bonds, determining the gel structure and properties of the system in aqueous media. In this study, we use all-atom molecular dynamics simulations to systematically analyze the interactions between alginic acid chains and Na+ and Ca2+ counterions. The formed alginates originate from the competition of intramolecular hydrogen bonding and water coordination around the polyelectrolyte. In contrast to the established interpretation, we show that calcium cations strongly bind to alginate by disrupting hydrogen bonds within (1 → 4)-linked β-d-mannuronate (M) residues. On the other hand, Na+ cations enhance intramolecular hydrogen bonds that stabilize a left-hand, fourfold helical chain structure in poly-M alginate, resulting in stiffer chains. Hence, the traditionally accepted flexible flat-chain model for poly-M sequence is not valid in the presence of Na+. The two cations have a distinct effect on water coordination around alginate and therefore on its solubility. While Ca+ disrupts water coordination directly around the alginate chains, mobile Na+ cations significantly disrupt the second hydration layer.
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Affiliation(s)
- Zezhong John Li
- Department of Chemical and Biological Engineering University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z3, Canada.,Laboratory of Sustainable and Catalytic Processing, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Simcha Srebnik
- Department of Chemical and Biological Engineering University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z3, Canada
| | - Orlando J Rojas
- Department of Chemical and Biological Engineering University of British Columbia, 2360 East Mall, Vancouver, British Columbia V6T 1Z3, Canada.,Bioproducts Institute, Department of Chemistry and Department of Wood Science, University of British Columbia, 2385 East Mall, Vancouver, British Columbia V6T 1Z4, Canada
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Sthoer A, Hladílková J, Lund M, Tyrode E. Molecular insight into carboxylic acid-alkali metal cations interactions: reversed affinities and ion-pair formation revealed by non-linear optics and simulations. Phys Chem Chem Phys 2019; 21:11329-11344. [PMID: 31107479 DOI: 10.1039/c9cp00398c] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Specific interactions between the carboxylic acid moiety and the monovalent salts CsCl, NaCl, and LiCl, have been investigated in Langmuir monolayers using vibrational sum frequency spectroscopy (VSFS) and complemented with coarse grained and all-atom molecular dynamics simulations. By exploiting VSFS's intrinsic surface specificity, an emphasis was made on targeting headgroup vibrations of both its charged and uncharged forms as well as water molecules in the interfacial layer. The degree of deprotonation of the monolayer as a function of cation concentration and pH was experimentally determined and theoretically rationalized. Starting from 100 mM, the surface charge was overestimated by the Gouy-Chapman model and varied depending on the identity of the cation, highlighting the appearance of ion specific effects. Agreement could be found using a modified Poisson-Boltzmann model that takes into account steric effects, with a fitted effective ion-size compatible with the hydrated ion diameters. The relative affinity of the cations to the carboxylic acid moiety was pH dependent: at pH 4.5 they arranged in the order Cs+ > Na+ > Li+, but fully reversed (Li+ > Na+ > Cs+) at pH 9. Simulations yielded microscopic insight into the origin of this behavior, with the cations showing contrasting interaction preferences for either the uncharged carboxylic acid or the charged carboxylate. Sum frequency spectra also provided evidence that all cations remained hydrated when interacting with the charged headgroup, forming solvent-separated or solvent-shared ion pairs. However, for the specific case of 1 M Li+ at pH 9, contact ion pairs were formed. Finally, the remarkable effect of trace metal multivalent cations in the interpretation of experiments is briefly discussed. The results provide exciting new insights into the complex interactions of alkali metal cations with the biophysically relevant carboxylic acid moiety.
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Affiliation(s)
- Adrien Sthoer
- Department of Chemistry, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
| | - Jana Hladílková
- Division of Theoretical Chemistry, Lund University, P.O.B. 124, SE-22100 Lund, Sweden
| | - Mikael Lund
- Division of Theoretical Chemistry, Lund University, P.O.B. 124, SE-22100 Lund, Sweden
| | - Eric Tyrode
- Department of Chemistry, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
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Houriez C, Vallet V, Réal F, Meot-Ner (Mautner) M, Masella M. Organic ion association in aqueous phase and ab initio-based force fields: The case of carboxylate/ammonium salts. J Chem Phys 2017; 147:161720. [DOI: 10.1063/1.4997996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Huggins DJ. Studying the role of cooperative hydration in stabilizing folded protein states. J Struct Biol 2016; 196:394-406. [PMID: 27633532 PMCID: PMC5131609 DOI: 10.1016/j.jsb.2016.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 09/03/2016] [Accepted: 09/07/2016] [Indexed: 01/19/2023]
Abstract
Understanding and modelling protein folding remains a key scientific and engineering challenge. Two key questions in protein folding are (1) why many proteins adopt a folded state and (2) how these proteins transition from the random coil ensemble to a folded state. In this paper we employ molecular dynamics simulations to address the first of these questions. Computational methods are well-placed to address this issue due to their ability to analyze systems at atomic-level resolution. Traditionally, the stability of folded proteins has been ascribed to the balance of two types of intermolecular interactions: hydrogen-bonding interactions and hydrophobic contacts. In this study, we explore a third type of intermolecular interaction: cooperative hydration of protein surface residues. To achieve this, we consider multiple independent simulations of the villin headpiece domain to quantify the contributions of different interactions to the energy of the native and fully extended states. In addition, we consider whether these findings are robust with respect to the protein forcefield, the water model, and the presence of salt. In all cases, we identify many cooperatively hydrated interactions that are transient but energetically favor the native state. Whilst further work on additional protein structures, forcefields, and water models is necessary, these results suggest a role for cooperative hydration in protein folding that should be explored further. Rational design of cooperative hydration on the protein surface could be a viable strategy for increasing protein stability.
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Affiliation(s)
- David J Huggins
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, 19 J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom; Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom.
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van der Vegt NFA, Haldrup K, Roke S, Zheng J, Lund M, Bakker HJ. Water-Mediated Ion Pairing: Occurrence and Relevance. Chem Rev 2016; 116:7626-41. [DOI: 10.1021/acs.chemrev.5b00742] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nico F. A. van der Vegt
- Eduard-Zintl-Institut
für Anorganische und Physikalische Chemie and Center of Smart
Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Strasse
10, 64287 Darmstadt, Germany
| | - Kristoffer Haldrup
- Physics
Department, NEXMAP Section, Technical University of Denmark, Fysikvej
307, 2800 Kongens
Lyngby, Denmark
| | - Sylvie Roke
- Laboratory
for Fundamental BioPhotonics, Institute of Bioengineering, and Institute
of Materials Science, School of Engineering, and Lausanne Centre for
Ultrafast Science, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Junrong Zheng
- College
of Chemistry and Molecular Engineering, Beijing National Laboratory
for Molecular Sciences, Peking University, Beijing 100871, China
- Department
of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005-1892, United States
| | - Mikael Lund
- Division
of Theoretical Chemistry, Department of Chemistry, Lund University, SE-22100 Lund, Sweden
| | - Huib J. Bakker
- FOM Institute AMOLF, Science
Park 104, 1098 XG Amsterdam, The Netherlands
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Choi JH, Cho M. Ion aggregation in high salt solutions. IV. Graph-theoretical analyses of ion aggregate structure and water hydrogen bonding network. J Chem Phys 2015; 143:104110. [DOI: 10.1063/1.4930608] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jun-Ho Choi
- Department of Chemistry, Korea University, Seoul 136-713, South Korea
| | - Minhaeng Cho
- Department of Chemistry, Korea University, Seoul 136-713, South Korea
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Korea University, Seoul 136-713, South Korea
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Zhang WJ, Hou GL, Wang P, Xu HG, Feng G, Xu XL, Zheng WJ. Microsolvation of sodium acetate in water: Anion photoelectron spectroscopy and ab initio calculations. J Chem Phys 2015; 143:054302. [DOI: 10.1063/1.4927668] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Wen-Jing Zhang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Gao-Lei Hou
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Peng Wang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Hong-Guang Xu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Gang Feng
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xi-Ling Xu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Wei-Jun Zheng
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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Choi JH, Cho M. Ion aggregation in high salt solutions. II. Spectral graph analysis of water hydrogen-bonding network and ion aggregate structures. J Chem Phys 2014; 141:154502. [DOI: 10.1063/1.4897638] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Jun-Ho Choi
- Department of Chemistry, Korea University, Seoul 136-713, South Korea
| | - Minhaeng Cho
- Department of Chemistry, Korea University, Seoul 136-713, South Korea
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Petit T, Lange KM, Conrad G, Yamamoto K, Schwanke C, Hodeck KF, Dantz M, Brandenburg T, Suljoti E, Aziz EF. Probing ion-specific effects on aqueous acetate solutions: Ion pairing versus water structure modifications. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2014; 1:034901. [PMID: 26798780 PMCID: PMC4711606 DOI: 10.1063/1.4884600] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/10/2014] [Indexed: 05/22/2023]
Abstract
The effect of monovalent cations (Li(+), K(+), NH4 (+), Na(+)) on the water structure in aqueous chloride and acetate solutions was characterized by oxygen K-edge X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy, and resonant inelastic X-ray scattering (RIXS) of a liquid microjet. We show ion- and counterion dependent effects on the emission spectra of the oxygen K-edge, which we attribute to modifications of the hydrogen bond network of water. For acetates, ion pairing with carboxylates was also probed selectively by XAS and RIXS. We correlate our experimental results to speciation data and to the salting-out properties of the cations.
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Affiliation(s)
- Tristan Petit
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) , Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Kathrin M Lange
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) , Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Gerrit Conrad
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) , Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | | | - Christoph Schwanke
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) , Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Kai F Hodeck
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) , Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | | | | | - Edlira Suljoti
- Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq) , Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
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11
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Mazur K, Buchner R, Bonn M, Hunger J. Hydration of Sodium Alginate in Aqueous Solution. Macromolecules 2014. [DOI: 10.1021/ma4023873] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Kamila Mazur
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Richard Buchner
- Institut
für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Johannes Hunger
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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