1
|
Harmon C, Bui A, Espejo JM, Gancayco M, Le JM, Rangel J, Eggers DK. Solvation free energy in governing equations for DNA hybridization, protein-ligand binding, and protein folding. FEBS Open Bio 2024. [PMID: 39289322 DOI: 10.1002/2211-5463.13897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 08/14/2024] [Accepted: 09/06/2024] [Indexed: 09/19/2024] Open
Abstract
This work examines the thermodynamics of model biomolecular interactions using a governing equation that accounts for the participation of bulk water in the equilibria. In the first example, the binding affinities of two DNA duplexes, one of nine and one of 10 base pairs in length, are measured and characterized by isothermal titration calorimetry (ITC) as a function of concentration. The results indicate that the change in solvation free energy that accompanies duplex formation (ΔGS) is large and unfavorable. The duplex with the larger number of G:C pairings yields the largest change in solvation free energy, ΔGS = +460 kcal·mol-1per base pair at 25 °C. A van't Hoff analysis of the data is complicated by the varying degree of intramolecular base stacking within each DNA strand as a function of temperature. A modeling study reveals how the solvation free energy alters the output of a typical ITC experiment and leads to a good, though misleading, fit to the classical equilibrium equation. The same thermodynamic framework is applied to a model protein-ligand interaction, the binding of ribonuclease A with the nucleotide inhibitor 3'-UMP, and to a conformational equilibrium, the change in tertiary structure of α-lactalbumin in molar guanidinium chloride solutions. The ribonuclease study yields a value of ΔGS = +160 kcal·mol-1, whereas the folding equilibrium yields ΔGS ≈ 0, an apparent characteristic of hydrophobic interactions. These examples provide insight on the role of solvation energy in binding equilibria and suggest a pivot in the fundamental application of thermodynamics to solution chemistry.
Collapse
Affiliation(s)
- Caroline Harmon
- Chemistry Department, San José State University, San José, CA, USA
| | - Austin Bui
- Chemistry Department, San José State University, San José, CA, USA
| | - Jasmin M Espejo
- Chemistry Department, San José State University, San José, CA, USA
| | - Marc Gancayco
- Chemistry Department, San José State University, San José, CA, USA
| | - Jennifer M Le
- Chemistry Department, San José State University, San José, CA, USA
| | - Juan Rangel
- Chemistry Department, San José State University, San José, CA, USA
| | - Daryl K Eggers
- Chemistry Department, San José State University, San José, CA, USA
| |
Collapse
|
2
|
Bag S, Dec R, Pezzotti S, Sahoo RR, Schwaab G, Winter R, Havenith M. Unraveling the hydration dynamics of ACC 1-13K 24 with ATP: From liquid to droplet to amyloid fibril. Biophys J 2024:S0006-3495(24)00603-9. [PMID: 39262114 DOI: 10.1016/j.bpj.2024.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 08/10/2024] [Accepted: 09/09/2024] [Indexed: 09/13/2024] Open
Abstract
In order to achieve a comprehensive understanding of protein aggregation processes, an exploration of solvation dynamics, a key yet intricate component of biological phenomena, is mandatory. In the present study, we used Fourier transform infrared spectroscopy and terahertz spectroscopy complemented by atomic force microscopy and kinetic experiments utilizing thioflavin T fluorescence to elucidate the changes in solvation dynamics during liquid-liquid phase separation and subsequent amyloid fibril formation, the latter representing a transition from liquid to solid phase separation. These processes are pivotal in the pathology of neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. We focus on the ACC1-13K24-ATP protein complex, which undergoes fibril formation followed by droplet generation. Our investigation reveals the importance of hydration as a driving force in these processes, offering new insights into the molecular mechanisms at play.
Collapse
Affiliation(s)
- Sampad Bag
- Physical Chemistry-II, Ruhr-University Bochum, Bochum, Germany
| | - Robert Dec
- Physical Chemistry I - Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany
| | - Simone Pezzotti
- Physical Chemistry-II, Ruhr-University Bochum, Bochum, Germany
| | - Rudhi Ranjan Sahoo
- National Institute of Science Education and Research, Bhubaneswar, India
| | - Gerhard Schwaab
- Physical Chemistry-II, Ruhr-University Bochum, Bochum, Germany
| | - Roland Winter
- Physical Chemistry I - Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany
| | | |
Collapse
|
3
|
Graziano G. Structural Order in the Hydration Shell of Nonpolar Groups versus that in Bulk Water. Chemphyschem 2024; 25:e202400102. [PMID: 38923744 DOI: 10.1002/cphc.202400102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 05/08/2024] [Indexed: 06/28/2024]
Abstract
The poor solubility of nonpolar compounds in water around room temperature is governed by a large and negative entropy change, whose molecular cause is still debated. Since the Frank and Evans original proposal in 1945, the large and negative entropy change is usually attributed to the formation of ordered structures in the hydration shell of nonpolar groups. However, the existence of such ordered structures has never been proven. The present study is aimed at providing available structural results and thermodynamic arguments disproving the existence of ordered structures in the hydration shell of nonpolar groups.
Collapse
Affiliation(s)
- Giuseppe Graziano
- Dipartimento di Scienze e Tecnologie, Università del Sannio, Via Francesco de Sanctis, snc, 82100, Benevento, Italy
| |
Collapse
|
4
|
Ramos S, Lee JC. Raman spectroscopy in the study of amyloid formation and phase separation. Biochem Soc Trans 2024; 52:1121-1130. [PMID: 38666616 PMCID: PMC11346453 DOI: 10.1042/bst20230599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 06/27/2024]
Abstract
Neurodegenerative diseases, such as Alzheimer's and Parkinson's, share a common pathological feature of amyloid structure accumulation. However, the structure-function relationship between these well-ordered, β-sheet-rich, filamentous protein deposits and disease etiology remains to be defined. Recently, an emerging hypothesis has linked phase separation, a process involved in the formation of protein condensates, to amyloid formation, suggesting that liquid protein droplets serve as loci for amyloid initiation. To elucidate how these processes contribute to disease progression, tools that can directly report on protein secondary structural changes are needed. Here, we review recent studies that have demonstrated Raman spectroscopy as a powerful vibrational technique for interrogating amyloid structures; one that offers sensitivity from the global secondary structural level to specific residues. This probe-free technique is further enhanced via coupling to a microscope, which affords structural data with spatial resolution, known as Raman spectral imaging (RSI). In vitro and in cellulo applications of RSI are discussed, highlighting studies of protein droplet aging, cellular internalization of fibrils, and Raman imaging of intracellular water. Collectively, utilization of the myriad Raman spectroscopic methods will contribute to a deeper understanding of protein conformational dynamics in the complex cellular milieu and offer potential clinical diagnostic capabilities for protein misfolding and aggregation processes in disease states.
Collapse
Affiliation(s)
- Sashary Ramos
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, U.S.A
| | - Jennifer C. Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, U.S.A
| |
Collapse
|
5
|
König B, Pezzotti S, Ramos S, Schwaab G, Havenith M. Real-time measure of solvation free energy changes upon liquid-liquid phase separation of α-elastin. Biophys J 2024; 123:1367-1375. [PMID: 37515326 PMCID: PMC11163292 DOI: 10.1016/j.bpj.2023.07.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/16/2023] [Accepted: 07/26/2023] [Indexed: 07/30/2023] Open
Abstract
Biological condensates are known to retain a large fraction of water to remain in a liquid and reversible state. Local solvation contributions from water hydrating hydrophilic and hydrophobic protein surfaces were proposed to play a prominent role for the formation of condensates through liquid-liquid phase separation (LLPS). However, although the total free energy is accessible by calorimetry, the partial solvent contributions to the free energy changes upon LLPS remained experimentally inaccessible so far. Here, we show that the recently developed THz calorimetry approach allows to quantify local hydration enthalpy and entropy changes upon LLPS of α-elastin in real time, directly from experimental THz spectroscopy data. We find that hydrophobic solvation dominates the entropic solvation term, whereas hydrophilic solvation mainly contributes to the enthalpy. Both terms are in the order of hundreds of kJ/mol, which is more than one order of magnitude larger than the total free energy changes at play during LLPS. However, since we show that entropy/enthalpy mostly compensates, a small entropy/enthalpy imbalance is sufficient to tune LLPS. Theoretically, a balance was proposed before. Here we present experimental evidence based on our spectroscopic approach. We finally show that LLPS can be steered by inducing small changes of solvation entropy/enthalpy compensation via concentration or temperature in α-elastin.
Collapse
Affiliation(s)
- Benedikt König
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum, Germany
| | - Simone Pezzotti
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum, Germany
| | - Sashary Ramos
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum, Germany
| | - Gerhard Schwaab
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum, Germany
| | - Martina Havenith
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum, Germany.
| |
Collapse
|
6
|
Mukherjee S, Ramos S, Pezzotti S, Kalarikkal A, Prass TM, Galazzo L, Gendreizig D, Barbosa N, Bordignon E, Havenith M, Schäfer LV. Entropy Tug-of-War Determines Solvent Effects in the Liquid-Liquid Phase Separation of a Globular Protein. J Phys Chem Lett 2024; 15:4047-4055. [PMID: 38580324 PMCID: PMC11033941 DOI: 10.1021/acs.jpclett.3c03421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/15/2024] [Accepted: 03/19/2024] [Indexed: 04/07/2024]
Abstract
Liquid-liquid phase separation (LLPS) plays a key role in the compartmentalization of cells via the formation of biomolecular condensates. Here, we combined atomistic molecular dynamics (MD) simulations and terahertz (THz) spectroscopy to determine the solvent entropy contribution to the formation of condensates of the human eye lens protein γD-Crystallin. The MD simulations reveal an entropy tug-of-war between water molecules that are released from the protein droplets and those that are retained within the condensates, two categories of water molecules that were also assigned spectroscopically. A recently developed THz-calorimetry method enables quantitative comparison of the experimental and computational entropy changes of the released water molecules. The strong correlation mutually validates the two approaches and opens the way to a detailed atomic-level understanding of the different driving forces underlying the LLPS.
Collapse
Affiliation(s)
- Saumyak Mukherjee
- Center
for Theoretical Chemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Sashary Ramos
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Simone Pezzotti
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Abhishek Kalarikkal
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Tobias M. Prass
- Center
for Theoretical Chemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Laura Galazzo
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Dominik Gendreizig
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
| | - Natercia Barbosa
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
| | - Enrica Bordignon
- Faculty
of Chemistry and Biochemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
- Department
of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
| | - Martina Havenith
- Department
of Physical Chemistry II, Ruhr University
Bochum, D-44780 Bochum, Germany
| | - Lars V. Schäfer
- Center
for Theoretical Chemistry, Ruhr University
Bochum, D-44780 Bochum, Germany
| |
Collapse
|
7
|
Mahanta DD, Brown DR, Webber T, Pezzotti S, Schwaab G, Han S, Shell MS, Havenith M. Bridging the Gap in Cryopreservation Mechanism: Unraveling the Interplay between Structure, Dynamics, and Thermodynamics in Cryoprotectant Aqueous Solutions. J Phys Chem B 2024; 128:3720-3731. [PMID: 38584393 DOI: 10.1021/acs.jpcb.4c00264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Cryoprotectants play a crucial role in preserving biological material, ensuring their viability during storage and facilitating crucial applications such as the conservation of medical compounds, tissues, and organs for transplantation. However, the precise mechanism by which cryoprotectants modulate the thermodynamic properties of water to impede the formation and growth of ice crystals, thus preventing long-term damage, remains elusive. This is evident in the use of empirically optimized recipes for mixtures that typically contain DMSO, glycerol, and various sugar constituents. Here, we use terahertz calorimetry, Overhauser nuclear polarization, and molecular dynamics simulations to show that DMSO exhibits a robust structuring effect on water around its methyl groups, reaching a maximum at a DMSO mole fraction of XDMSO = 0.33. In contrast, glycerol exerts a smaller water-structuring effect, even at higher concentrations (Scheme 1). These results potentially suggest that the wrapped water around DMSO's methyl group, which can be evicted upon ligand binding, may render DMSO a more surface-active cryoprotectant than glycerol, while glycerol may participate more as a viscogen that acts on the entire sample. These findings shed light on the molecular intricacies of cryoprotectant solvation behavior and have potentially significant implications for optimizing cryopreservation protocols.
Collapse
Affiliation(s)
- Debasish Das Mahanta
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany
- Department of Physics, Technische Universität (TU) Dortmund, Dortmund 44227, Germany
| | - Dennis Robinson Brown
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | - Thomas Webber
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | - Simone Pezzotti
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany
| | - Gerhard Schwaab
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany
| | - Songi Han
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, United States
| | - M Scott Shell
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | - Martina Havenith
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany
- Department of Physics, Technische Universität (TU) Dortmund, Dortmund 44227, Germany
| |
Collapse
|
8
|
Tao YH, Schulke S, Schwaab G, Nealon GL, Pezzotti S, Hodgetts SI, Harvey AR, Havenith M, Wallace VP. Hydration water drives the self-assembly of guanosine monophosphate. Biophys J 2024; 123:931-939. [PMID: 38454599 PMCID: PMC11052693 DOI: 10.1016/j.bpj.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/04/2024] [Accepted: 03/04/2024] [Indexed: 03/09/2024] Open
Abstract
Guanosine monophosphate (GMP) is a nucleotide that can self-assemble in aqueous solution under certain conditions. An understanding of the process at the molecular level is an essential step to comprehend the involvement of DNA substructures in transcription and replication, as well as their relationship to genetic diseases such as cancer. We present the temperature-dependent terahertz (1.5-12 THz, 50-400 cm-1) absorptivity spectra of aqueous Na2 GMP solution in comparison with the aqueous solutions of other RNA nucleotides. Distinct absorption features were observed in the spectrum of GMP, which we attribute to the intramolecular modes of the self-assemblies (i.e., G-complexes) that, at 1 M, start to form at 313 K and below. Changes in broad-band features of the terahertz spectrum were also observed, which we associate with the release of hydration water in the temperature-dependent formation of guanine quadruplexes. Using a state-of-the-art THz calorimetry approach correlating spectroscopic to thermodynamic changes, we propose a molecular mechanism of hydrophilic hydration driving GMP self-assembly as a function of temperature. The free energy contribution of hydrophilic hydration is shown as a decisive factor in guanine-quadruplex formation. Our findings spotlight the role of hydration in the formation of macromolecular structures and suggest the potential of hydration tuning for regulating DNA transcription and replication.
Collapse
Affiliation(s)
- Yu Heng Tao
- Department of Physics, The University of Western Australia, Crawley, WA, Australia
| | - Simon Schulke
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany
| | - Gerhard Schwaab
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany
| | - Gareth L Nealon
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia; Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA, Australia
| | - Simone Pezzotti
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany
| | - Stuart I Hodgetts
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia
| | - Alan R Harvey
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia
| | - Martina Havenith
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany.
| | - Vincent P Wallace
- Department of Physics, The University of Western Australia, Crawley, WA, Australia.
| |
Collapse
|
9
|
Serva A, Pezzotti S. S.O.S: Shape, orientation, and size tune solvation in electrocatalysis. J Chem Phys 2024; 160:094707. [PMID: 38426524 DOI: 10.1063/5.0186925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/05/2024] [Indexed: 03/02/2024] Open
Abstract
Current models to understand the reactivity of metal/aqueous interfaces in electrochemistry, e.g., volcano plots, are based on the adsorption free energies of reactants and products, which are often small hydrophobic molecules (such as in CO2 and N2 reduction). Calculations played a major role in the quantification and comprehension of these free energies in terms of the interactions that the reactive species form with the surface. However, solvation free energies also come into play in two ways: (i) by modulating the adsorption free energy together with solute-surface interactions, as the solute has to penetrate the water adlayer in contact with the surface and get partially desolvated (which costs free energy); (ii) by regulating transport across the interface, i.e., the free energy profile from the bulk to the interface, which is strongly non-monotonic due to the unique nature of metal/aqueous interfaces. Here, we use constant potential molecular dynamics to study the solvation contributions, and we uncover huge effects of the shape and orientation (on top of the already known size effect) of small hydrophobic and amphiphilic solutes on their adsorption free energy. We propose a minimal theoretical model, the S.O.S. model, that accounts for size, orientation, and shape effects. These novel aspects are rationalized by recasting the concepts at the base of the Lum-Chandler-Weeks theory of hydrophobic solvation (for small solutes in the so-called volume-dominated regime) into a layer-by-layer form, where the properties of each interfacial region close to the metal are explicitly taken into account.
Collapse
Affiliation(s)
- Alessandra Serva
- Sorbonne Université, CNRS, Physico-Chimie des Electrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France
| | - Simone Pezzotti
- PASTEUR, Département de Chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| |
Collapse
|
10
|
Schulke S, Nolten M, Schwaab G, Havenith M. Studying Local Electrostatics by Terahertz Spectroscopy Using Amines as a Probe. Chemphyschem 2024; 25:e202300389. [PMID: 37897334 DOI: 10.1002/cphc.202300389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 09/20/2023] [Accepted: 10/26/2023] [Indexed: 10/30/2023]
Abstract
In a previous study[1] we could show that a large amplitude mode of the zwitterion glycine can serve as a sensitive probe for protonation and allows to deduce local pKa values. Here we show that the underlying concept is more general: We present the results of a pH dependent measurement of Terahertz-FTIR (THz-FTIR) spectra of solvated amines, i. e. Diethylamine (DEA), Triethylamine (TEA), and Diisopropylamine (DiPA). We show that amines serve as a sensitive, label free probe for local protonation. Protonation of the amines yield intensity changes which can be quantified by precise THz spectroscopy (30 cm-1 -450 cm-1 ). A detailed analysis allows us to correlate the titration spectra of solvated amines in the THz range with pKa values. This demonstrates the potential of THz spectroscopy to probe the charge state of biomolecules in water in a label free manner.
Collapse
Affiliation(s)
- Simon Schulke
- Physical Chemistry 2, Ruhr-Univeristy Bochum, Universitaetsstraße 150, 44801, Bochum, Germany
| | - Melinda Nolten
- Physical Chemistry 2, Ruhr-Univeristy Bochum, Universitaetsstraße 150, 44801, Bochum, Germany
| | - Gerhard Schwaab
- Physical Chemistry 2, Ruhr-Univeristy Bochum, Universitaetsstraße 150, 44801, Bochum, Germany
| | - Martina Havenith
- Physical Chemistry 2, Ruhr-Univeristy Bochum, Universitaetsstraße 150, 44801, Bochum, Germany
| |
Collapse
|
11
|
Pyne S, Pyne P, Mitra RK. The explicit role of interfacial hydration during polyethylene glycol induced lipid fusion: a THz spectroscopic investigation. Phys Chem Chem Phys 2023; 25:31326-31334. [PMID: 37960951 DOI: 10.1039/d3cp04868c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
While the phenomenon of excipient mediated membrane fusion has been studied widely, the inherent role of interfacial hydration involved in the process has mostly remained unaddressed. Here we report the experimental validation of the fact that PEG-induced membrane fusion is associated with the dehydration of the membrane(s). We explore the explicit hydration behavior at three different lipids (DOPC, POPC and DPPC) membranes with different aliphatic tails as they undergo fusogenic transition in the presence of PEG of average molecular weight of 4000 using THz-FTIR spectroscopy in the frequency window of 1.5-13.5 THz. Dynamic light scattering and electron microscopic measurements confirm the formation of different intermediate steps of the liposomes during the fusion process: bilayer aggregation, destabilization and finally lipid fusion. We observe that membrane hydration follows a systematic trend with the lipid specificity as the fusion process sets in.
Collapse
Affiliation(s)
- Sumana Pyne
- Department of Chemical and Biological Sciences, S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India.
| | - Partha Pyne
- Department of Chemical and Biological Sciences, S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India.
| | - Rajib Kumar Mitra
- Department of Chemical and Biological Sciences, S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700106, India.
| |
Collapse
|
12
|
Ockelmann T, Hoberg C, Buchmann A, Novelli F, Havenith M. Energy Dissipation into the Solvent during Proton Transfer Occurs via Acoustic Phonons. J Phys Chem B 2023; 127:9560-9565. [PMID: 37879121 DOI: 10.1021/acs.jpcb.3c04874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
In photochemistry, rapid energy dissipation into the solvent is mandatory to prevent radiation damages. By optical pump THz spectroscopy, we are able to follow the details of the energy dissipation mechanism upon photoexcitation of the photoacid to the hydrogen-bonded network of water: Based on the frequency maps subsequent to photoexcitation, we propose that energy transfer takes place via propagation of an acoustic phonon. The dissipation into the solvent can be rationalized by an initial first hydration shell response followed by energy dissipation via an acoustic phonon. Surprisingly, for the first 10 ps, the propagation in the water network can be described by a wave packet with a constant group velocity, indicating a long-range correlation. After 300 ps, thermalization in the liquid jet is reached and the THz spectrum reflects a Boltzmann population, corresponding a temperature increase of ΔT = 0.5 °C.
Collapse
Affiliation(s)
- Thorsten Ockelmann
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
| | - Claudius Hoberg
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
| | - Adrian Buchmann
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
| | - Fabio Novelli
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
| | - Martina Havenith
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
| |
Collapse
|
13
|
Bag S, Pezzotti S, Das Mahanta D, Schulke S, Schwaab G, Havenith M. From Local Hydration Motifs in Aqueous Acetic Acid Solutions to Macroscopic Mixing Thermodynamics: A Quantitative Connection from THz-Calorimetry. J Phys Chem B 2023; 127:9204-9210. [PMID: 37843511 DOI: 10.1021/acs.jpcb.3c06328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
We report the results of THz measurements (30-440 cm-1) of aqueous acetic acid solutions over the full mixing range (XAcAc = 0-1). We recorded spectroscopic observables as a function of the acetic acid concentration in the frequency range of the intermolecular stretch at 150 cm-1 and of the librational modes at 350-440 cm-1. This allowed us to unravel changes in hydrophobic and hydrophilic hydration motifs, respectively. By means of a novel THz-calorimetry approach, we quantitatively correlated these changes in local hydration motifs to excess mixing entropy and enthalpy. We find that ΔHmix is determined by both hydrophobic and hydrophilic solvation contributions. In contrast, ΔSmix is governed by hydrophobic cavity formation. Our results further suggest that acetic acid-water mixtures are systems at the edge of phase separation due to endothermic contributions from both hydrophilic and hydrophobic solvation in a large portion of the miscibility range. Our work establishes a quantitative relationship between the balance of local hydrophobic and hydrophilic solvation motifs and the macroscopic mixing thermodynamic properties.
Collapse
Affiliation(s)
- Sampad Bag
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany
| | - Simone Pezzotti
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany
| | - Debasish Das Mahanta
- Department of Physics, Gandhi Institute of Technology and Management (GITAM), Bengaluru, Karnataka 561203, India
| | - Simon Schulke
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany
| | - Gerhard Schwaab
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany
| | - Martina Havenith
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany
| |
Collapse
|
14
|
Majumdar BB, Pyne P, Mitra RK, Das Mahanta D. Impact of hydrophobicity on local solvation structures and its connection with the global solubilization thermodynamics of amphiphilic molecules. Phys Chem Chem Phys 2023; 25:27161-27169. [PMID: 37789695 DOI: 10.1039/d3cp02741d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The relationship between the local solvation structures and global thermodynamics, specifically in the case of amphiphilic molecules, is a complex phenomenon and is not yet fully understood. With the prior knowledge that local solvation structures can impose a significant impact on the overall solvation process, we here combine THz spectroscopic analysis with MD simulations to investigate the impact of the altered hydrophobicity and polarity of amphiphilic solute molecules on the local solvation configurations. We use two water soluble alcohols: ethanol (EtOH) and its fluorinated counterpart, 2,2,2-trifluoroethanol (TFE), as model solutes. Our study is aimed to determine the relative abundance of different hydrogen bonded conformers and to establish a correlation between the spectral signatures (as obtained from THz spectroscopic measurements) and microscopic solute-solvent interactions associated with the local solvation structures (as obtained from MD simulations). Finally, we estimate the possible energetic parameters associated with the alcohol solubilization process. We found that while both the alcohols are completely water soluble, they receive a contrasting solvation energy share in terms of entropy and enthalpy. We understand that these findings are not limited to the specific system studied here but can be broadly extrapolated to other amphiphilic aqueous solutions.
Collapse
Affiliation(s)
- Bibhab Bandhu Majumdar
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700106, India.
| | - Partha Pyne
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700106, India.
| | - Rajib Kumar Mitra
- Department of Chemical and Biological Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700106, India.
| | - Debasish Das Mahanta
- Department of Chemistry, The University of Texas at Austin, 105 E 24th 4 Street, Austin, TX 78712, USA.
| |
Collapse
|
15
|
Chakraborty S, Bhattacharya I, Mitra RK. Solvation Plays a Key Role in Antioxidant-Mediated Attenuation of Elevated Creatinine Level: An In Vitro Spectroscopic Investigation. J Phys Chem B 2023; 127:8576-8585. [PMID: 37769128 DOI: 10.1021/acs.jpcb.3c05334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
An elevated level of creatinine (CRN) is a mark of kidney ailment, and prolonged retention of such condition could lead to renal failure, associated with severe ischemia. Antioxidants are clinically known to excrete CRN from the body through urine, thereby reducing its level in blood. The molecular mechanism of such an exclusion process is still illusive. As the excretion channel is urine, solvation of the solute is expected to play a pivotal role. Here, we report a detailed time-domain and frequency-domain terahertz (THz) spectroscopic investigation to understand the solvation of CRN in the presence of two model antioxidants, mostly used to treat elevated CRN level: N-Acetyl-l-cysteine (NAC) and ascorbic acid (ASC). FTIR spectroscopy in the mid-infrared region and UV absorption spectroscopy measurements coupled with quantum chemical calculations [at the B3LYP/6-311G++(d,p) level] reveal that both NAC and ASC form HBonded complexes with CRN and rapidly undergo a barrier-less proton transfer process to form creatinium ions. THz measurements provide explicit evidence of the formation of highly solvated complexes compared with bare CRN, which eventually enables its excretion through urine. These observations could provide a foundation for designing more beneficial drugs to resolve kidney diseases..
Collapse
Affiliation(s)
- Subhadip Chakraborty
- Department of Chemical and Biological Sciences, S.N. Bose National Centre for Basic Sciences; Block-JD; Sector-III; Salt Lake, Kolkata 700106, India
| | - Indrani Bhattacharya
- Department of Chemical and Biological Sciences, S.N. Bose National Centre for Basic Sciences; Block-JD; Sector-III; Salt Lake, Kolkata 700106, India
| | - Rajib Kumar Mitra
- Department of Chemical and Biological Sciences, S.N. Bose National Centre for Basic Sciences; Block-JD; Sector-III; Salt Lake, Kolkata 700106, India
| |
Collapse
|
16
|
Das Mahanta D, Brown DR, Pezzotti S, Han S, Schwaab G, Shell MS, Havenith M. Local solvation structures govern the mixing thermodynamics of glycerol-water solutions. Chem Sci 2023; 14:7381-7392. [PMID: 37416713 PMCID: PMC10321518 DOI: 10.1039/d3sc00517h] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 06/12/2023] [Indexed: 07/08/2023] Open
Abstract
Glycerol is a major cryoprotective agent and is widely used to promote protein stabilization. By a combined experimental and theoretical study, we show that global thermodynamic mixing properties of glycerol and water are dictated by local solvation motifs. We identify three hydration water populations, i.e., bulk water, bound water (water hydrogen bonded to the hydrophilic groups of glycerol) and cavity wrap water (water hydrating the hydrophobic moieties). Here, we show that for glycerol experimental observables in the THz regime allow quantification of the abundance of bound water and its partial contribution to the mixing thermodynamics. Specifically, we uncover a 1 : 1 connection between the population of bound waters and the mixing enthalpy, which is further corroborated by the simulation results. Therefore, the changes in global thermodynamic quantity - mixing enthalpy - are rationalized at the molecular level in terms of changes in the local hydrophilic hydration population as a function of glycerol mole fraction in the full miscibility range. This offers opportunities to rationally design polyol water, as well as other aqueous mixtures to optimize technological applications by tuning mixing enthalpy and entropy based on spectroscopic screening.
Collapse
Affiliation(s)
- Debasish Das Mahanta
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
- Department of Physics, Technische Universität Dortmund 44227 Dortmund Germany
| | - Dennis Robinson Brown
- Department of Chemical Engineering, University of California Santa Barbara California 93106-5080 USA
| | - Simone Pezzotti
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
| | - Songi Han
- Department of Chemical Engineering, University of California Santa Barbara California 93106-5080 USA
- Department of Chemistry and Biochemistry, University of California Santa Barbara California 93106-9510 USA
| | - Gerhard Schwaab
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
| | - M Scott Shell
- Department of Chemical Engineering, University of California Santa Barbara California 93106-5080 USA
| | - Martina Havenith
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
- Department of Physics, Technische Universität Dortmund 44227 Dortmund Germany
| |
Collapse
|
17
|
Hoberg C, Talbot JJ, Shee J, Ockelmann T, Das Mahanta D, Novelli F, Head-Gordon M, Havenith M. Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine. Chem Sci 2023; 14:4048-4058. [PMID: 37063810 PMCID: PMC10094129 DOI: 10.1039/d2sc07126f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 03/09/2023] [Indexed: 03/18/2023] Open
Abstract
Photo-induced excited-state proton transfer (ESPT) reactions are of central importance in many biological and chemical processes. Identifying mechanistic details of the solvent reorganizations that facilitate proton transfer however, is challenging for current experimental and theoretical approaches. Using optical pump THz probe (OPTP) spectroscopy and molecular dynamics simulations, we were able to elucidate the ultrafast changes in the solvation environment for three derivatives of pyranine: the photoacid HPTS, the methoxy derivative MPTS, and the photobase OPTS. Experimentally, we find damped oscillations in the THz signal at short times and our simulations enable their assignment to vibrational energy transfer beatings between the photoexcited chromophore and nearby solvent molecules. The simulations of HPTS reveal strikingly efficient sub-ps energy transfer into a particular solvent mode, that is active near 4 THz, and which can provide the requisite energy required for solvent reorganization promoting proton transfer. Similar oscillations are present in the THz signal for all three derivatives, however the signal is damped rapidly for HPTS (within 0.4 ps) and more slowly for MPTS (within 1.4 ps) and OPTS (within 2.0 ps). For HPTS, we also characterize an additional phonon-like propagation of the proton into the bulk with a 140 ps period and an 83 ps damping time. Thermalization of the solvent occurs on a time scale exceeding 120 ps.
Collapse
Affiliation(s)
- Claudius Hoberg
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
| | - Justin J Talbot
- Department of Chemistry, University of California Berkeley California 94720 USA
| | - James Shee
- Department of Chemistry, University of California Berkeley California 94720 USA
| | - Thorsten Ockelmann
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
| | - Debasish Das Mahanta
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
| | - Fabio Novelli
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
| | - Martin Head-Gordon
- Department of Chemistry, University of California Berkeley California 94720 USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley California 94720 USA
| | - Martina Havenith
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
| |
Collapse
|
18
|
Abstract
The photo-induced radiolysis of water is an elementary reaction in biology and chemistry, forming solvated electrons, OH radicals, and hydronium cations on fast time scales. Here, we use an optical-pump terahertz-probe spectroscopy setup to trigger the photoionization of water molecules with optical laser pulses at ~400 nm and then time-resolve the transient solvent response with broadband terahertz (THz) fields with a ~90 fs time resolution. We observe three distinct spectral responses. The first is a positive broadband mode that can be attributed to an initial diffuse, delocalized electron with a radius of (22 ± 1) Å, which is short lived (<200 fs) because the absorption is blue-shifting outside of the THz range. The second emerging spectroscopic signature with a lifetime of about 150 ps is attributed to an intermolecular mode associated with a mass rearrangement of solvent molecules due to charge separation of radicals and hydronium cations. After 0.2 ps, we observe a long-lasting THz signature with depleted intensity at 110 cm-1 that is well reproduced by ab initio molecular dynamics. We interpret this negative band at 110 cm-1 as the solvent cage characterized by a weakening of the hydrogen bond network in the first and second hydration shells of the cavity occupied by the localized electron.
Collapse
|
19
|
Pezzotti S, König B, Ramos S, Schwaab G, Havenith M. Liquid-Liquid Phase Separation? Ask the Water! J Phys Chem Lett 2023; 14:1556-1563. [PMID: 36745512 DOI: 10.1021/acs.jpclett.2c02697] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Water is more than an inert spectator during liquid-liquid phase separation (LLPS), the reversible compartmentalization of protein solutions into a protein-rich and a dilute phase. We show that LLPS is driven by changes in hydration entropy and enthalpy. Tuning LLPS by adjusting experimental parameters, e.g., addition of co-solutes, is a major goal for biological and medical applications. This requires a general model to quantify thermodynamic driving forces. Here, we develop such a model based on the measured amplitudes of characteristic THz-features of two hydration populations: "Cavity-wrap" water hydrating hydrophobic patches is released during LLPS leading to an increase in entropy. "Bound" water hydrating hydrophilic patches is retained since it is enthalpically favorable. We introduce a THz-phase diagram mapping these spectroscopic/thermodynamic changes. This provides not only a precise understanding of hydrophobic and hydrophilic hydration driving forces as a function of temperature and concentration but also a rational means to tune LLPS.
Collapse
Affiliation(s)
- Simone Pezzotti
- Department of Physical Chemistry II, Ruhr University Bochum, 44801Bochum, Germany
| | - Benedikt König
- Department of Physical Chemistry II, Ruhr University Bochum, 44801Bochum, Germany
| | - Sashary Ramos
- Department of Physical Chemistry II, Ruhr University Bochum, 44801Bochum, Germany
| | - Gerhard Schwaab
- Department of Physical Chemistry II, Ruhr University Bochum, 44801Bochum, Germany
| | - Martina Havenith
- Department of Physical Chemistry II, Ruhr University Bochum, 44801Bochum, Germany
- Department of Physics, Technische Universität Dortmund, 44227Dortmund, Germany
| |
Collapse
|
20
|
Miranda-Quintana RA, Smiatek J. Electronic properties of amino acids and nucleobases: similarity classes and pairing principles from chemical reactivity indices. Phys Chem Chem Phys 2022; 24:22477-22486. [PMID: 36106477 DOI: 10.1039/d2cp02767d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a new classification scheme for amino acids and nucleobases based on the electronic properties of the individual molecules. Using chemical reactivity indices such as electronegativity, electrophilicity, and chemical hardness, we can identify similarities and differences between each class of amino acids and nucleobases. Notable differences emerge in particular with regard to high, neutral or low electronegativity as well as different combinations of chemical hardness. Our approach allows us to relate these insights to the properties of the side groups in terms of a unique reference scheme. We further show that hydrophobic differences between amino acids are rather negligible in the context of electronic properties. Our classification scheme also rationalizes the occurrence of distinct stable nucleobase pairs and clearly emphasizes certain differences between individual molecules. The stability and abundant occurrence of Watson-Crick nucleobase pairs is further discussed in the context of the minimum electrophilicity principle.
Collapse
Affiliation(s)
| | - Jens Smiatek
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, D-70569 Stuttgart, Germany.
| |
Collapse
|
21
|
A subtle interplay between hydrophilic and hydrophobic hydration governs butanol (de)mixing in water. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.140080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
22
|
Pezzotti S, Sebastiani F, van Dam EP, Ramos S, Conti Nibali V, Schwaab G, Havenith M. Spectroscopic Fingerprints of Cavity Formation and Solute Insertion as a Measure of Hydration Entropic Loss and Enthalpic Gain. Angew Chem Int Ed Engl 2022; 61:e202203893. [PMID: 35500074 PMCID: PMC9401576 DOI: 10.1002/anie.202203893] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Indexed: 11/09/2022]
Abstract
Hydration free energies are dictated by a subtle balance of hydrophobic and hydrophilic interactions. We present here a spectroscopic approach, which gives direct access to the two main contributions: Using THz-spectroscopy to probe the frequency range of the intermolecular stretch (150-200 cm-1 ) and the hindered rotations (450-600 cm-1 ), the local contributions due to cavity formation and hydrophilic interactions can be traced back. We show that via THz calorimetry these fingerprints can be correlated 1 : 1 with the group specific solvation entropy and enthalpy. This allows to deduce separately the hydrophobic (i.e. cavity formation) and hydrophilic contributions to thermodynamics, as shown for hydrated alcohols as a case study. Accompanying molecular dynamics simulations quantitatively support our experimental results. In the future our approach will allow to dissect hydration contributions in inhomogeneous mixtures and under non-equilibrium conditions.
Collapse
Affiliation(s)
- Simone Pezzotti
- Department of Physical Chemistry IIRuhr University BochumBochumGermany
| | - Federico Sebastiani
- Department of Physical Chemistry IIRuhr University BochumBochumGermany
- Current affiliation: Department of Chemistry “U. Schiff”University of FlorenceI-50019Sesto FiorentinoFIItaly
| | - Eliane P. van Dam
- Department of Physical Chemistry IIRuhr University BochumBochumGermany
| | - Sashary Ramos
- Department of Physical Chemistry IIRuhr University BochumBochumGermany
| | - Valeria Conti Nibali
- Department of Physical Chemistry IIRuhr University BochumBochumGermany
- Current affiliation: Dipartimento di Scienze Matematiche e InformaticheScienze Fisiche e Scienze della Terra (MIFT)Università di Messina98166MessinaItaly
| | - Gerhard Schwaab
- Department of Physical Chemistry IIRuhr University BochumBochumGermany
| | - Martina Havenith
- Department of Physical Chemistry IIRuhr University BochumBochumGermany
- Department of PhysicsTechnische Universität Dortmund44227DortmundGermany
| |
Collapse
|