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Rudani BA, Jakubowski A, Kriegs H, Wiegand S. Deciphering the guanidinium cation: Insights into thermal diffusion. J Chem Phys 2024; 160:214502. [PMID: 38828819 DOI: 10.1063/5.0215843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 05/16/2024] [Indexed: 06/05/2024] Open
Abstract
Thermophoresis, or thermodiffusion, is becoming a more popular method for investigating the interactions between proteins and ligands due to its high sensitivity to the interactions between solutes and water. Despite its growing use, the intricate mechanisms behind thermodiffusion remain unclear. This gap in knowledge stems from the complexities of thermodiffusion in solvents that have specific interactions as well as the intricate nature of systems that include many components with both non-ionic and ionic groups. To deepen our understanding, we reduce complexity by conducting systematic studies on aqueous salt solutions. In this work, we focused on how guanidinium salt solutions behave in a temperature gradient, using thermal diffusion forced Rayleigh scattering experiments at temperatures ranging from 15 to 35 °C. We looked at the thermodiffusive behavior of four guanidinium salts (thiocyanate, iodide, chloride, and carbonate) in solutions with concentrations ranging from 1 to 3 mol/kg. The guanidinium cation is disk-shaped and is characterized by flat hydrophobic surfaces and three amine groups, which enable directional hydrogen bonding along the edges. We compare our results to the behavior of salts with spherical cations, such as sodium, potassium, and lithium. Our discussions are framed around how different salts are solvated, specifically in the context of the Hofmeister series, which ranks ions based on their effects on the solvation of proteins.
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Affiliation(s)
- Binny A Rudani
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Andre Jakubowski
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Hartmut Kriegs
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Simone Wiegand
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
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2
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Krevert CS, Gunkel L, Haese C, Hunger J. Ion-specific binding of cations to the carboxylate and of anions to the amide of alanylalanine. Commun Chem 2022; 5:173. [PMID: 36697920 PMCID: PMC9814750 DOI: 10.1038/s42004-022-00789-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022] Open
Abstract
Studies of ion-specific effects on oligopeptides have aided our understanding of Hofmeister effects on proteins, yet the use of different model peptides and different experimental sensitivities have led to conflicting conclusions. To resolve these controversies, we study a small model peptide, L-Alanyl-L-alanine (2Ala), carrying all fundamental chemical protein motifs: C-terminus, amide bond, and N-terminus. We elucidate the effect of GdmCl, LiCl, KCl, KI, and KSCN by combining dielectric relaxation, nuclear magnetic resonance (1H-NMR), and (two-dimensional) infrared spectroscopy. Our dielectric results show that all ions reduce the rotational mobility of 2Ala, yet the magnitude of the reduction is larger for denaturing cations than for anions. The NMR chemical shifts of the amide group are particularly sensitive to denaturing anions, indicative of anion-amide interactions. Infrared experiments reveal that LiCl alters the spectral homogeneity and dynamics of the carboxylate, but not the amide group. Interaction of LiCl with the negatively charged pole of 2Ala, the COO- group, can explain the marked cationic effect on dipolar rotation, while interaction of anions between the poles, at the amide, only weakly perturbs dipolar dynamics. As such, our results provide a unifying view on ions' preferential interaction sites at 2Ala and help rationalize Hofmeister effects on proteins.
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Affiliation(s)
- Carola Sophie Krevert
- grid.419547.a0000 0001 1010 1663Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Lucas Gunkel
- grid.419547.a0000 0001 1010 1663Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Constantin Haese
- grid.419547.a0000 0001 1010 1663Department of Molecular Electronics, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Johannes Hunger
- grid.419547.a0000 0001 1010 1663Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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3
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dos Santos AP, Uematsu Y, Rathert A, Loche P, Netz RR. Consistent description of ion-specificity in bulk and at interfaces by solvent implicit simulations and mean-field theory. J Chem Phys 2020; 153:034103. [DOI: 10.1063/5.0016103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alexandre P. dos Santos
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 Porto Alegre, RS, Brazil
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Yuki Uematsu
- Department of Physics, Kyushu University, 819-0395 Fukuoka, Japan
| | | | - Philip Loche
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Roland R. Netz
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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4
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The cation effect on the solubility of glycylglycine and N-acetylglycine in aqueous solution: Experimental and molecular dynamics studies. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Bruce EE, Bui PT, Rogers BA, Cremer PS, van der Vegt NFA. Nonadditive Ion Effects Drive Both Collapse and Swelling of Thermoresponsive Polymers in Water. J Am Chem Soc 2019; 141:6609-6616. [DOI: 10.1021/jacs.9b00295] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Ellen E. Bruce
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, D-64287 Darmstadt, Germany
| | - Pho T. Bui
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Bradley A. Rogers
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Paul S. Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nico F. A. van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, D-64287 Darmstadt, Germany
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6
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Balos V, Marekha B, Malm C, Wagner M, Nagata Y, Bonn M, Hunger J. Spezifische Ionen-Effekte am Beispiel eines Oligopeptids: die Rolle zweizähniger Koordination beim Guanidinium-Kation. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201811029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Vasileios Balos
- Arbeitskreis molekulare Spektroskopie; Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Deutschland
- Derzeitige Adresse: Abteilung für physikalische Chemie; Fritz Haber Institut der Max-Planck-Gesellschaft; Faradayweg 4 14195 Berlin Deutschland
| | - Bogdan Marekha
- Arbeitskreis molekulare Spektroskopie; Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Deutschland
| | - Christian Malm
- Arbeitskreis molekulare Spektroskopie; Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Deutschland
| | - Manfred Wagner
- Arbeitskreis molekulare Spektroskopie; Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Deutschland
| | - Yuki Nagata
- Arbeitskreis molekulare Spektroskopie; Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Deutschland
| | - Mischa Bonn
- Arbeitskreis molekulare Spektroskopie; Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Deutschland
| | - Johannes Hunger
- Arbeitskreis molekulare Spektroskopie; Max-Planck-Institut für Polymerforschung; Ackermannweg 10 55128 Mainz Deutschland
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Balos V, Marekha B, Malm C, Wagner M, Nagata Y, Bonn M, Hunger J. Specific Ion Effects on an Oligopeptide: Bidentate Binding Matters for the Guanidinium Cation. Angew Chem Int Ed Engl 2019; 58:332-337. [PMID: 30403434 DOI: 10.1002/anie.201811029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 10/24/2018] [Indexed: 01/11/2023]
Abstract
Ion-protein interactions are important for protein function, yet challenging to rationalize owing to the multitude of possible ion-protein interactions. To explore specific ion effects on protein binding sites, we investigate the interaction of different salts with the zwitterionic peptide triglycine in solution. Dielectric spectroscopy shows that salts affect the peptide's reorientational dynamics, with a more pronounced effect for denaturing cations (Li+ , guanidinium (Gdm+ )) and anions (I- , SCN- ) than for weakly denaturing ones (K+ , Cl- ). The effects of Gdm+ and Li+ were found to be comparable. Molecular dynamics simulations confirm the enhanced binding of Gdm+ and Li+ to triglycine, yet with a different binding geometry: While Li+ predominantly binds to the C-terminal carboxylate group, bidentate binding to the terminus and the nearest amide is particularly important for Gdm+ . This bidentate binding markedly affects peptide conformation, and may help to explain the high denaturation activity of Gdm+ salts.
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Affiliation(s)
- Vasileios Balos
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.,Present address: Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4, 14195, Berlin, Germany
| | - Bogdan Marekha
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Christian Malm
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Manfred Wagner
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Yuki Nagata
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Mischa Bonn
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Johannes Hunger
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
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Mukherjee K, Schwaab G, Havenith M. Cation-specific interactions of protein surface charges in dilute aqueous salt solutions: a combined study using dielectric relaxation spectroscopy and Raman spectroscopy. Phys Chem Chem Phys 2018; 20:29306-29313. [PMID: 30444249 DOI: 10.1039/c8cp05011b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We exploited glycine as a zwitterionic model system to experimentally probe the cation specific interaction of protein surface charges in dilute (≤0.25 mol L-1) aqueous solutions of four biologically relevant inorganic salts, NaCl, KCl, MgCl2 and CaCl2, via dielectric relaxation spectroscopy (DRS) and Raman spectroscopy. Glycine is the simplest building block of proteins and it exposes the same charged groups (carboxylate and ammonium) to the solvent that dominate the protein-water interface. As a counter ion, we selected Cl- due to its biological importance. For all systems, we performed simultaneous fitting of the real (ε') and imaginary (ε″) parts of the dielectric functions, assuming a multimodal relaxation model, obtained from concentration dependent dielectric measurements at ∼293 K. We observe a reduction of the dielectric amplitude for the glycine relaxation while the corresponding time constant shows only small (<7%) deviations compared to aqueous glycine solutions. We propose that the observed reduction in dielectric amplitude is due to a reduction of the effective dipole moment (µeff) of zwitterionic glycine caused by the interaction of glycine with the ion even at very low (0.05 M) salt concentrations. The interaction between divalent metal ions and zwitterionic glycine is increased compared to the monovalent cation-zwitterion interaction; a finding that is also supported by Raman spectroscopy. Our combined dielectric relaxation and Raman spectroscopic study indicates that ion-glycine interactions are weak and mediated by the solvent. Cation-specificity of protein surface charges is also observed in dilute salt solutions (≤0.25 mol L-1), where electrostatic interactions dominate.
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Affiliation(s)
- K Mukherjee
- Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Physical Chemistry 2, Germany.
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Zhang Q, Pan Z, Zhang L, Zhang R, Chen Z, Jin T, Wu T, Chen X, Zhuang W. Ion effect on the dynamics of water hydrogen bonding network: A theoretical and computational spectroscopy point of view. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1373] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Qiang Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
- Department of ChemistryBohai UniversityJinzhouChina
| | - Zhijun Pan
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Ruiting Zhang
- School of Physics and Optoelectronic EngineeringXidian UniversityXi'anChina
| | - Zhening Chen
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Tan Jin
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Tianmin Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Xian Chen
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Wei Zhuang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
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Cota R, Ottosson N, Bakker HJ, Woutersen S. Evidence for Reduced Hydrogen-Bond Cooperativity in Ionic Solvation Shells from Isotope-Dependent Dielectric Relaxation. PHYSICAL REVIEW LETTERS 2018; 120:216001. [PMID: 29883173 DOI: 10.1103/physrevlett.120.216001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 01/08/2018] [Indexed: 06/08/2023]
Abstract
We find that the reduction in dielectric response (depolarization) of water caused by solvated ions is different for H_{2}O and D_{2}O. This isotope dependence allows us to reliably determine the kinetic contribution to the depolarization, which is found to be significantly smaller than predicted by existing theory. The discrepancy can be explained from a reduced hydrogen-bond cooperativity in the solvation shell: we obtain quantitative agreement between theory and experiment by reducing the Kirkwood correlation factor of the solvating water from 2.7 (the bulk value) to ∼1.6 for NaCl and ∼1 (corresponding to completely uncorrelated motion of water molecules) for CsCl.
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Affiliation(s)
- Roberto Cota
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | | | - Huib J Bakker
- AMOLF, Science Park 104, 1098 XG Amsterdam, Netherlands
| | - Sander Woutersen
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
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