1
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Liu YZ, Chen YN, Sun Q. The Dependence of Hydrophobic Interactions on the Shape of Solute Surface. Molecules 2024; 29:2601. [PMID: 38893477 PMCID: PMC11173737 DOI: 10.3390/molecules29112601] [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: 04/28/2024] [Revised: 05/26/2024] [Accepted: 05/29/2024] [Indexed: 06/21/2024] Open
Abstract
According to our recent studies on hydrophobicity, this work is aimed at understanding the dependence of hydrophobic interactions on the shape of a solute's surface. It has been observed that dissolved solutes primarily affect the structure of interfacial water, which refers to the top layer of water at the interface between the solute and water. As solutes aggregate in a solution, hydrophobic interactions become closely related to the transition of water molecules from the interfacial region to the bulk water. It is inferred that hydrophobic interactions may depend on the shape of the solute surface. To enhance the strength of hydrophobic interactions, the solutes tend to aggregate, thereby minimizing their surface area-to-volume ratio. This also suggests that hydrophobic interactions may exhibit directional characteristics. Moreover, this phenomenon can be supported by calculated potential mean forces (PMFs) using molecular dynamics (MD) simulations, where different surfaces, such as convex, flat, or concave, are associated with a sphere. Furthermore, this concept can be extended to comprehend the molecular packing parameter, commonly utilized in studying the self-assembly behavior of amphiphilic molecules in aqueous solutions.
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Affiliation(s)
| | | | - Qiang Sun
- Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, The School of Earth and Space Sciences, Peking University, Beijing 100871, China; (Y.-Z.L.); (Y.-N.C.)
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2
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Crago M, Lee A, Hoang TP, Talebian S, Naficy S. Protein adsorption on blood-contacting surfaces: A thermodynamic perspective to guide the design of antithrombogenic polymer coatings. Acta Biomater 2024; 180:46-60. [PMID: 38615811 DOI: 10.1016/j.actbio.2024.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 04/16/2024]
Abstract
Blood-contacting medical devices often succumb to thrombosis, limiting their durability and safety in clinical applications. Thrombosis is fundamentally initiated by the nonspecific adsorption of proteins to the material surface, which is strongly governed by thermodynamic factors established by the nature of the interaction between the material surface, surrounding water molecules, and the protein itself. Along these lines, different surface materials (such as polymeric, metallic, ceramic, or composite) induce different entropic and enthalpic changes at the surface-protein interface, with material wettability significantly impacting this behavior. Consequently, protein adsorption on medical devices can be modulated by altering their wettability and surface energy. A plethora of polymeric coating modifications have been utilized for this purpose; hydrophobic modifications may promote or inhibit protein adsorption determined by van der Waals forces, while hydrophilic materials achieve this by mainly relying on hydrogen bonding, or unbalanced/balanced electrostatic interactions. This review offers a cohesive understanding of the thermodynamics governing these phenomena, to specifically aid in the design and selection of hemocompatible polymeric coatings for biomedical applications. STATEMENT OF SIGNIFICANCE: Blood-contacting medical devices often succumb to thrombosis, limiting their durability and safety in clinical applications. A plethora of polymeric coating modifications have been utilized for addressing this issue. This review offers a cohesive understanding of the thermodynamics governing these phenomena, to specifically aid in the design and selection of hemocompatible polymeric coatings for biomedical applications.
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Affiliation(s)
- Matthew Crago
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia
| | - Aeryne Lee
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia
| | - Thanh Phuong Hoang
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia
| | - Sepehr Talebian
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia.
| | - Sina Naficy
- School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2008, Australia.
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3
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Koonin EV, Kuhn JH, Dolja VV, Krupovic M. Megataxonomy and global ecology of the virosphere. THE ISME JOURNAL 2024; 18:wrad042. [PMID: 38365236 PMCID: PMC10848233 DOI: 10.1093/ismejo/wrad042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/22/2023] [Accepted: 12/28/2023] [Indexed: 02/18/2024]
Abstract
Nearly all organisms are hosts to multiple viruses that collectively appear to be the most abundant biological entities in the biosphere. With recent advances in metagenomics and metatranscriptomics, the known diversity of viruses substantially expanded. Comparative analysis of these viruses using advanced computational methods culminated in the reconstruction of the evolution of major groups of viruses and enabled the construction of a virus megataxonomy, which has been formally adopted by the International Committee on Taxonomy of Viruses. This comprehensive taxonomy consists of six virus realms, which are aspired to be monophyletic and assembled based on the conservation of hallmark proteins involved in capsid structure formation or genome replication. The viruses in different major taxa substantially differ in host range and accordingly in ecological niches. In this review article, we outline the latest developments in virus megataxonomy and the recent discoveries that will likely lead to reassessment of some major taxa, in particular, split of three of the current six realms into two or more independent realms. We then discuss the correspondence between virus taxonomy and the distribution of viruses among hosts and ecological niches, as well as the abundance of viruses versus cells in different habitats. The distribution of viruses across environments appears to be primarily determined by the host ranges, i.e. the virome is shaped by the composition of the biome in a given habitat, which itself is affected by abiotic factors.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, United States
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, United States
| | - Valerian V Dolja
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, United States
| | - Mart Krupovic
- Institut Pasteur, Université Paris Cité, Archaeal Virology Unit, 75015 Paris, France
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4
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Machado LO, Reis D, Figueiredo Neto AM. The Soret coefficient of human low-density lipoprotein in solution: a thermophilic behavior. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:124. [PMID: 38060052 DOI: 10.1140/epje/s10189-023-00377-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 11/10/2023] [Indexed: 12/08/2023]
Abstract
Thermodiffusion, or Soret effect, is the physical phenomenon of matter gradients originated by the migration of chemical species induced by thermal gradients. Thermodiffusion has been widely applied in the study of colloidal suspensions. In this study, we investigate the termodiffusion behavior of low-density lipoprotein (LDL) particles, by the Soret coefficient measurement. It is a new approach to studies of plasma lipoproteins. The experimental work was based on thermal- and Soret-lens effects. These effects were induced by laser irradiation of the samples, at two different time scales, in a Z-scan setup. LDL samples were analyzed under physiological conditions, notedly, ionic strength and pH, and at different temperatures. Temperature dependence of Soret coefficient showed a slight decrease in the absolute value of this coefficient, as a function of temperature increasing. However, its sign does not change at the temperatures investigated (15, 22.5 and 37.5 °C). The results show that LDL particles exhibit thermophilic behavior. The origin of this thermophilic behavior is not yet completely understood. We discuss some aspects that can be related with the Soret effect in LDL samples.
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Affiliation(s)
| | - Dennys Reis
- Institute of Physics, University of São Paulo, São Paulo, Brazil
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5
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Sahu S, Ghosh S, Sinha SK, Datta S, Sengupta N. Thermal Sensitivity of the Enzymatic Activity of β-Glucosidase: Simulations Lend Mechanistic Insights into Experimental Observations. Biochemistry 2023; 62:3440-3452. [PMID: 37997958 DOI: 10.1021/acs.biochem.3c00387] [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: 11/25/2023]
Abstract
A crucial prerequisite for industrial applications of enzymes is the maintenance of specific activity across wide thermal ranges. β-Glucosidase (EC 3.2.1.21) is an essential enzyme for converting cellulose in biomass to glucose. While the reaction mechanisms of β-glucosidases from various thermal ranges (hyperthermophilic, thermophilic, and mesophilic) are similar, the factors underlying their thermal sensitivity remain obscure. The work presented here aims to unravel the molecular mechanisms underlying the thermal sensitivity of the enzymatic activity of the β-glucosidase BglB from the bacterium Paenibacillus polymyxa. Experiments reveal a maximum enzymatic activity at 315 K, with a marked decrease in the activity below and above this temperature. Employing in silico simulations, we identified the crucial role of the active site tunnel residues in the thermal sensitivity. Specific tunnel residues were identified via energetic decomposition and protein-substrate hydrogen bond analyses. The experimentally observed trends in specific activity with temperature coincide with variations in overall binding free energy changes, showcasing a predominantly electrostatic effect that is consistent with enhanced catalytic pocket-substrate hydrogen bonding (HB) at Topt. The entropic advantage owing to the HB substate reorganization was found to facilitate better substrate binding at 315 K. This study elicits molecular-level insights into the associative mechanisms between thermally enabled fluctuations and enzymatic activity. Crucial differences emerge between molecular mechanisms involving the actual substrate (cellobiose) and a commonly employed chemical analogue. We posit that leveraging the role of fluctuations may reveal unexpected insights into enzyme behavior and offer novel paradigms for enzyme engineering.
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Affiliation(s)
- Sneha Sahu
- Protein Engineering Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Sayani Ghosh
- Protein Engineering Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Sushant K Sinha
- Protein Engineering Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Supratim Datta
- Protein Engineering Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
- Center for the Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
- Center for the Climate and Environmental Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
| | - Neelanjana Sengupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
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6
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Ramos S, Kamps J, Pezzotti S, Winklhofer KF, Tatzelt J, Havenith M. Hydration makes a difference! How to tune protein complexes between liquid-liquid and liquid-solid phase separation. Phys Chem Chem Phys 2023; 25:28063-28069. [PMID: 37840355 DOI: 10.1039/d3cp03299j] [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: 10/17/2023]
Abstract
Understanding how protein rich condensates formed upon liquid-liquid phase separation (LLPS) evolve into solid aggregates is of fundamental importance for several medical applications, since these are suspected to be hot-spots for many neurotoxic diseases. This requires developing experimental approaches to observe in real-time both LLPS and liquid-solid phase separation (LSPS), and to unravel the delicate balance of protein and water interactions dictating the free energy differences between the two. We present a vibrational THz spectroscopy approach that allows doing so from the point of view of hydration water. We focus on a cellular prion protein of high medical relevance, which we can drive to undergo either LLPS or LSPS with few mutations. We find that it is a subtle balance of hydrophobic and hydrophilic solvation contributions that allows tuning between LLPS and LSPS. Hydrophobic hydration provides an entropic driving force to phase separation, through the release of hydration water into the bulk. Water hydrating hydrophilic groups provides an enthalpic driving force to keep the condensates in a liquid state. As a result, when we modify the protein by a few mutations to be less hydrophilic, we shift from LLPS to LSPS. This molecular understanding paves the way for a rational design of proteins.
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Affiliation(s)
- Sashary Ramos
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany.
| | - Janine Kamps
- Department of Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Simone Pezzotti
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany.
| | - Konstanze F Winklhofer
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr Unviersity Bochum, Bochum, Germany
| | - Jörg Tatzelt
- Department of Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Martina Havenith
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany.
- Department of Physics, TU Dortmund, Dortmund, Germany
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7
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Saha D, Jana B. Decoupling of Interactions between Model-Charged Peptides Reveals Key Factors Responsible for Liquid-Liquid Phase Separation. J Phys Chem B 2023; 127:6656-6667. [PMID: 37480340 DOI: 10.1021/acs.jpcb.3c03087] [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: 07/24/2023]
Abstract
Liquid-liquid phase separation (LLPS) by disordered proteins has been shown to govern biological processes and cause numerous diseases. Therefore, a deeper understanding of the interactions and their variation with external factors is key to modulating the LLPS behavior of different systems and protecting proteins from pathological aggregation. In this context, we have looked at interactions between similarly charged peptides to understand the molecular features that may drive or prevent condensate formation under various conditions. We have studied dimer formation for model peptides where charged and noncharged amino acids have been placed alternatively. Using arginine and glutamic acid as the charged residues and varying the other residues with glycine, alanine, and proline to alter hydrophobicity, we have obtained the free-energy surface (FES) for the dimer formation for these systems under high salt concentration at two different temperatures using all-atom molecular dynamics simulations and the well-tempered metadynamics method. Our results indicate that a combination of effects such as hydrophobicity, arginine-arginine interactions, or water release from the solvation shell makes dimerization free energy more favorable for the positively charged peptides with lower flexibility. For the negatively charged peptides, the crucial role of water has been found in governing the FES. Systems having charged residues and phenylalanine in the peptide sequence also have been studied at high salt concentrations using unbiased simulations. In this case, only the positively charged peptides were found to aggregate through temperature-dependent hydrophobic and cation-π interactions. Overall, our study indicates that the negatively charged peptides are more likely to remain in the dilute phase under various conditions compared to the positively charged systems. The findings from our study would be helpful in designing and controlling systems to obtain LLPS behavior for therapeutic usage.
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Affiliation(s)
- Debasis Saha
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Biman Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India
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8
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Chen S, Li Z, Voth GA. Acidic Conditions Impact Hydrophobe Transfer across the Oil-Water Interface in Unusual Ways. J Phys Chem B 2023; 127:3911-3918. [PMID: 37084419 PMCID: PMC10166083 DOI: 10.1021/acs.jpcb.3c00828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/09/2023] [Indexed: 04/23/2023]
Abstract
Molecular dynamics simulation and enhanced free energy sampling are used to study hydrophobic solute transfer across the water-oil interface with explicit consideration of the effect of different electrolytes: hydronium cation (hydrated excess proton) and sodium cation, both with chloride counterions (i.e., dissociated acid and salt, HCl and NaCl). With the Multistate Empirical Valence Bond (MS-EVB) methodology, we find that, surprisingly, hydronium can to a certain degree stabilize the hydrophobic solute, neopentane, in the aqueous phase and including at the oil-water interface. At the same time, the sodium cation tends to "salt out" the hydrophobic solute in the expected fashion. When it comes to the solvation structure of the hydrophobic solute in the acidic conditions, hydronium shows an affinity to the hydrophobic solute, as suggested by the radial distribution functions (RDFs). Upon consideration of this interfacial effect, we find that the solvation structure of the hydrophobic solute varies at different distances from the oil-liquid interface due to a competition between the bulk oil phase and the hydrophobic solute phase. Together with an observed orientational preference of the hydroniums and the lifetime of water molecules in the first solvation shell of neopentane, we conclude that hydronium stabilizes to a certain degree the dispersal of neopentane in the aqueous phase and eliminates any salting out effect in the acid solution; i.e., the hydronium acts like a surfactant. The present molecular dynamics study provides new insight into the hydrophobic solute transfer across the water-oil interface process, including for acid and salt solutions.
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Affiliation(s)
- Sijia Chen
- Department of Chemistry, Chicago Center
for Theoretical Chemistry, The James Franck Institute, and Institute
for Biophysical Dynamics, The University
of Chicago, Chicago, Illinois 60637, United States
| | - Zhefu Li
- Department of Chemistry, Chicago Center
for Theoretical Chemistry, The James Franck Institute, and Institute
for Biophysical Dynamics, The University
of Chicago, Chicago, Illinois 60637, United States
| | - Gregory A. Voth
- Department of Chemistry, Chicago Center
for Theoretical Chemistry, The James Franck Institute, and Institute
for Biophysical Dynamics, The University
of Chicago, Chicago, Illinois 60637, United States
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9
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Shin W, Yang ZJ. Computational Strategies for Entropy Modeling in Chemical Processes. Chem Asian J 2023; 18:e202300117. [PMID: 36882367 DOI: 10.1002/asia.202300117] [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: 02/10/2023] [Revised: 03/03/2023] [Accepted: 03/05/2023] [Indexed: 03/09/2023]
Abstract
Computational simulations of entropy are important in understanding the thermodynamic forces that drive chemical reactions on a molecular scale. In recent years, various algorithms have been developed and applied in conjunction with molecular modeling techniques to evaluate the change of entropy in solvation, hydrophobic interactions, and chemical reactions. The aim of this review is to highlight four specific computational entropy calculation methods: normal mode analysis, free volume theory, two-phase thermodynamics, and configurational entropy modeling. The technical aspects, applications, and limitations of each method will be discussed in detail.
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Affiliation(s)
- Wook Shin
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, 37235, United States
| | - Zhongyue J Yang
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, 37235, United States.,Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, 37235, United States.,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, 37235, United States.,Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, 37235, United States.,Data Science Institute, Vanderbilt University, Nashville, Tennessee, 37235, United States
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10
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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.
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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
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11
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Dallin BC, Kelkar AS, Van Lehn RC. Structural features of interfacial water predict the hydrophobicity of chemically heterogeneous surfaces. Chem Sci 2023; 14:1308-1319. [PMID: 36756335 PMCID: PMC9891380 DOI: 10.1039/d2sc02856e] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 01/02/2023] [Indexed: 01/04/2023] Open
Abstract
The hydrophobicity of an interface determines the magnitude of hydrophobic interactions that drive numerous biological and industrial processes. Chemically heterogeneous interfaces are abundant in these contexts; examples include the surfaces of proteins, functionalized nanomaterials, and polymeric materials. While the hydrophobicity of nonpolar solutes can be predicted and related to the structure of interfacial water molecules, predicting the hydrophobicity of chemically heterogeneous interfaces remains a challenge because of the complex, non-additive contributions to hydrophobicity that depend on the chemical identity and nanoscale spatial arrangements of polar and nonpolar groups. In this work, we utilize atomistic molecular dynamics simulations in conjunction with enhanced sampling and data-centric analysis techniques to quantitatively relate changes in interfacial water structure to the hydration free energy (a thermodynamically well-defined descriptor of hydrophobicity) of chemically heterogeneous interfaces. We analyze a large data set of 58 self-assembled monolayers (SAMs) composed of ligands with nonpolar and polar end groups of different chemical identity (amine, amide, and hydroxyl) in five mole fractions, two spatial patterns, and with scaled partial charges. We find that only five features of interfacial water structure are required to accurately predict hydration free energies. Examination of these features reveals mechanistic insights into the interfacial hydrogen bonding behaviors that distinguish different surface compositions and patterns. This analysis also identifies the probability of highly coordinated water structures as a unique signature of hydrophobicity. These insights provide a physical basis to understand the hydrophobicity of chemically heterogeneous interfaces and connect hydrophobicity to experimentally accessible perturbations of interfacial water structure.
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Affiliation(s)
- Bradley C. Dallin
- Department of Chemical and Biological Engineering, University of Wisconsin – Madison1415 Engineering DriveMadisonWI53706USA+1-608-263-9487
| | - Atharva S. Kelkar
- Department of Chemical and Biological Engineering, University of Wisconsin – Madison1415 Engineering DriveMadisonWI53706USA+1-608-263-9487
| | - Reid C. Van Lehn
- Department of Chemical and Biological Engineering, University of Wisconsin – Madison1415 Engineering DriveMadisonWI53706USA+1-608-263-9487
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12
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The Hydrophobic Effect Studied by Using Interacting Colloidal Suspensions. Int J Mol Sci 2023; 24:ijms24032003. [PMID: 36768326 PMCID: PMC9916416 DOI: 10.3390/ijms24032003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/14/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023] Open
Abstract
Interactions between nanoparticles (NPs) determine their self-organization and dynamic processes. In these systems, a quantitative description of the interparticle forces is complicated by the presence of the hydrophobic effect (HE), treatable only qualitatively, and due to the competition between the hydrophobic and hydrophilic forces. Recently, instead, a sort of crossover of HE from hydrophilic to hydrophobic has been experimentally observed on a local scale, by increasing the temperature, in pure confined water and studying the occurrence of this crossover in different water-methanol solutions. Starting from these results, we then considered the idea of studying this process in different nanoparticle solutions. By using photon correlation spectroscopy (PCS) experiments on dendrimer with OH terminal groups (dissolved in water and methanol, respectively), we show the existence of this hydrophobic-hydrophilic crossover with a well defined temperature and nanoparticle volume fraction dependence. In this frame, we have used the mode coupling theory extended model to evaluate the measured time-dependent density correlation functions (ISFs). In this context we will, therefore, show how the measured spectra are strongly dependent on the specificity of the interactions between the particles in solution. The observed transition demonstrates that just the HE, depending sensitively on the system thermodynamics, determines the hydrophobic and hydrophilic interaction properties of the studied nanostructures surface.
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13
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Reddy KD, Biswas R. Hydrophobic Hydration: A Theoretical Investigation of Structure and Dynamics. J CHEM SCI 2023. [DOI: 10.1007/s12039-022-02123-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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14
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Stefaniuk A, Gawinkowski S, Golec B, Gorski A, Szutkowski K, Waluk J, Poznański J. Isotope effects observed in diluted D 2O/H 2O mixtures identify HOD-induced low-density structures in D 2O but not H 2O. Sci Rep 2022; 12:18732. [PMID: 36333587 PMCID: PMC9636167 DOI: 10.1038/s41598-022-23551-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022] Open
Abstract
Normal and heavy water are solvents most commonly used to study the isotope effect. The isotope effect of a solvent significantly influences the behavior of a single molecule in a solution, especially when there are interactions between the solvent and the solute. The influence of the isotope effect becomes more significant in D2O/H2O since the hydrogen bond in H2O is slightly weaker than its counterpart (deuterium bond) in D2O. Herein, we characterize the isotope effect in a mixture of normal and heavy water on the solvation of a HOD molecule. We show that the HOD molecule affects the proximal solvent molecules, and these disturbances are much more significant in heavy water than in normal water. Moreover, in D2O, we observe the formation of low-density structures indicative of an ordering of the solvent around the HOD molecule. The qualitative differences between HOD interaction with D2O and H2O were consistently confirmed with Raman spectroscopy and NMR diffusometry.
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Affiliation(s)
- Anna Stefaniuk
- grid.418825.20000 0001 2216 0871Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Sylwester Gawinkowski
- grid.425290.80000 0004 0369 6111Institute of Physical Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Barbara Golec
- grid.425290.80000 0004 0369 6111Institute of Physical Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Aleksander Gorski
- grid.425290.80000 0004 0369 6111Institute of Physical Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Kosma Szutkowski
- grid.5633.30000 0001 2097 3545Adam Mickiewicz University, NanoBioMedical Centre, Wszechnicy Piastowskiej 3, 61-614 Poznan, Poland
| | - Jacek Waluk
- grid.425290.80000 0004 0369 6111Institute of Physical Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland ,grid.440603.50000 0001 2301 5211Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
| | - Jarosław Poznański
- grid.418825.20000 0001 2216 0871Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
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15
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Sinha I, Cramer SM, Ashbaugh HS, Garde S. Connecting Non-Gaussian Water Density Fluctuations to the Lengthscale Dependent Crossover in Hydrophobic Hydration. J Phys Chem B 2022; 126:7604-7614. [PMID: 36154059 DOI: 10.1021/acs.jpcb.2c04990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We connect density fluctuations in liquid water to lengthscale dependent crossover in hydrophobic hydration. Specifically, we employ indirect umbrella sampling (INDUS) simulations to characterize density fluctuations in observation volumes of various sizes and shapes in water and as a function of temperature and salt concentration. Consistent with previous observations, density fluctuations are Gaussian in small molecular scale volumes, but they display non-Gaussian "low-density fat tails" in larger volumes. These non-Gaussian tails are indicative of the proximity of water to its liquid to vapor phase transition and have implications on biomolecular interactions and function. We show that the onset of non-Gaussian fluctuations in large volumes is accompanied by the formation of a cavity in the observation volume. We develop a model that uses the physics of cavity-water interface formation as a key ingredient and show that it captures the nature of non-Gaussian density fluctuations over a broad region in water and in salt solutions. We discuss the limitations of this model in the very low density region of the distribution. Our calculations provide new insights into the origins of non-Gaussian density fluctuations in water and their connections to lengthscale dependent crossover in hydrophobic hydration.
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Affiliation(s)
- Imee Sinha
- Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
| | - Steven M Cramer
- Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
| | - Henry S Ashbaugh
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70123, United States
| | - Shekhar Garde
- Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
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16
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Buell AK. Stability matters, too - the thermodynamics of amyloid fibril formation. Chem Sci 2022; 13:10177-10192. [PMID: 36277637 PMCID: PMC9473512 DOI: 10.1039/d1sc06782f] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 01/30/2022] [Indexed: 12/26/2022] Open
Abstract
Amyloid fibrils are supramolecular homopolymers of proteins that play important roles in biological functions and disease. These objects have received an exponential increase in attention during the last few decades, due to their role in the aetiology of a range of severe disorders, most notably some of a neurodegenerative nature. While an overwhelming number of experimental studies exist that investigate how, and how fast, amyloid fibrils form and how their formation can be inhibited, a much more limited body of experimental work attempts to answer the question as to why these types of structures form (i.e. the thermodynamic driving force) and how stable they actually are. In this review, I attempt to give an overview of the types of experiments that have been performed to-date to answer these questions, and to summarise our current understanding of amyloid thermodynamics.
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Affiliation(s)
- Alexander K Buell
- Technical University of Denmark, Department of Biotechnology and Biomedicine Søltofts Plads, Building 227 2800 Kgs. Lyngby Denmark
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17
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Waibl F, Fernández-Quintero ML, Wedl FS, Kettenberger H, Georges G, Liedl KR. Comparison of hydrophobicity scales for predicting biophysical properties of antibodies. Front Mol Biosci 2022; 9:960194. [PMID: 36120542 PMCID: PMC9475378 DOI: 10.3389/fmolb.2022.960194] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
While antibody-based therapeutics have grown to be one of the major classes of novel medicines, some antibody development candidates face significant challenges regarding expression levels, solubility, as well as stability and aggregation, under physiological and storage conditions. A major determinant of those properties is surface hydrophobicity, which promotes unspecific interactions and has repeatedly proven problematic in the development of novel antibody-based drugs. Multiple computational methods have been devised for in-silico prediction of antibody hydrophobicity, often using hydrophobicity scales to assign values to each amino acid. Those approaches are usually validated by their ability to rank potential therapeutic antibodies in terms of their experimental hydrophobicity. However, there is significant diversity both in the hydrophobicity scales and in the experimental methods, and consequently in the performance of in-silico methods to predict experimental results. In this work, we investigate hydrophobicity of monoclonal antibodies using hydrophobicity scales. We implement several scoring schemes based on the solvent-accessibility and the assigned hydrophobicity values, and compare the different scores and scales based on their ability to predict retention times from hydrophobic interaction chromatography. We provide an overview of the strengths and weaknesses of several commonly employed hydrophobicity scales, thereby improving the understanding of hydrophobicity in antibody development. Furthermore, we test several datasets, both publicly available and proprietary, and find that the diversity of the dataset affects the performance of hydrophobicity scores. We expect that this work will provide valuable guidelines for the optimization of biophysical properties in future drug discovery campaigns.
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Affiliation(s)
- Franz Waibl
- Department of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | | | - Florian S. Wedl
- Department of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Hubert Kettenberger
- Large Molecule Research, Roche Pharma Research and Early Development, Roche Innovation Center Munich, Penzberg, Germany
| | - Guy Georges
- Large Molecule Research, Roche Pharma Research and Early Development, Roche Innovation Center Munich, Penzberg, Germany
| | - Klaus R. Liedl
- Department of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
- *Correspondence: Klaus R. Liedl,
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18
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Teschke O, Castro JR, Gomes WE, Soares DM. Variable Interfacial Water Nanosized Arrangements Measured by Atomic Force Microscopy. ACS OMEGA 2022; 7:28875-28884. [PMID: 36033701 PMCID: PMC9404190 DOI: 10.1021/acsomega.2c01982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 07/28/2022] [Indexed: 06/15/2023]
Abstract
While there seems to be broad agreement that cluster formation does exist near solid surfaces, its presence at the liquid/vapor interface is controversial. We report experimental studies we have carried out on interfacial water attached on hydrophobic and hydrophilic surfaces. Nanosized steps in the measured force vs distance to the surface curves characterize water cluster profiles. An expansion of the interfacial structure with time is observed; the initial profile extent is typically ∼1 nm, and for longer times expanded structures of ∼70 nm are observed. Our previous results showed that the interfacial water structure has a relative permittivity of ε ≈ 3 at the air/water interface homogeneously increasing to ε ≈ 80 at 300 nm inside the bulk, but here we have shown that the interfacial dielectric permittivity may have an oscillating profile describing the spatial steps in the force vs distance curves. This low dielectric permittivity arrangements of clusters extend the region with ε ≈ 3 inside bulk water and exhibit a behavior similar to that of water networks that expand in time.
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Affiliation(s)
- Omar Teschke
- Laboratorio
de Nanoestruturas e Interfaces, Instituto de Fisica, UNICAMP, 13083-859 Campinas, São
Paulo, Brazil
| | - Jose Roberto Castro
- Laboratorio
de Nanoestruturas e Interfaces, Instituto de Fisica, UNICAMP, 13083-859 Campinas, São
Paulo, Brazil
| | - Wyllerson Evaristo Gomes
- Pontificia
Universidade Catolica de Campinas, Faculdade de Quimica, 13012-970 Campinas, São Paulo, Brazil
| | - David Mendez Soares
- Laboratorio
de Nanoestruturas e Interfaces, Instituto de Fisica, UNICAMP, 13083-859 Campinas, São
Paulo, Brazil
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19
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Loche P, Scalfi L, Ali Amu M, Schullian O, Bonthuis D, Rotenberg B, Netz RR. Effects of surface rigidity and metallicity on dielectric properties and ion interactions at aqueous hydrophobic interfaces. J Chem Phys 2022; 157:094707. [DOI: 10.1063/5.0101509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using classical molecular dynamics simulations we investigate the dielectric properties at interfaces of water with graphene, graphite, hexane and water vapor. For graphite we compare metallic and non-metallic versions. At the vapor-liquid water and hexane-water interfaces the laterally averaged dielectric profiles are significantly broadened due to interfacial roughness and only slightly anisotropic. In contrast, at the rigid graphene surface the dielectric profiles are strongly anisotropic and the perpendicular dielectric profile exhibits pronounced oscillations and sign changes. The interfacial dielectric excess, characterized by the shift of the dielectric-dividing-surface with respect to the Gibbs-dividing-surface, is positive for all surfaces, showing that water has an enhanced dielectric response at hydrophobic surfaces. The dielectric-dividing-surface positions vary significantly among the different surfaces, which points to pronounced surface-specific dielectric behavior. The interfacial repulsion of a chloride ion is shown to be dominated by electrostatic interactions for the soft fluid-fluid interfaces and by non-electrostatic Lennard-Jones interactions for the rigid graphene-water interface. A linear tensorial dielectric model for the ion-interface interaction with sharp dielectric interfaces located on the dielectric-dividing-surface positions works well for graphene but fails for vapor and hexane, because these interfaces are smeared out. The repulsion of chloride from the metallic and non-metallic graphite versions differs very little, which reflects the almost identical interfacial water structure and can be understood based on linear continuum dielectric theory. Interface flexibility shows up mostly in the non-linear Coulomb part of the ion-interface interaction, which changes significantly close to the interfaces and signals the breakdown of linear dielectric continuum theory.
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Affiliation(s)
| | - Laura Scalfi
- Freie Universitat Berlin Fachbereich Physik, Germany
| | | | - Otto Schullian
- Max Planck Institute of Colloids and Interfaces, Germany
| | - Douwe Bonthuis
- Institute of Theoretical and Computational Physics, Graz University of Technology Institute of Theoretical and Computational Physics, Austria
| | | | - Roland R. Netz
- Physics, Freie Universitat Berlin Fachbereich Physik, Germany
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20
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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] [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.
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Affiliation(s)
- Simone Pezzotti
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany
| | - Federico Sebastiani
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany.,Current affiliation: Department of Chemistry "U. Schiff", University of Florence, I-50019, Sesto Fiorentino, FI, Italy
| | - Eliane P van Dam
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany
| | - Sashary Ramos
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany
| | - Valeria Conti Nibali
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany.,Current affiliation: Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra (MIFT), Università di Messina, 98166, Messina, Italy
| | - Gerhard Schwaab
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany
| | - Martina Havenith
- Department of Physical Chemistry II, Ruhr University Bochum, Bochum, Germany.,Department of Physics, Technische Universität Dortmund, 44227, Dortmund, Germany
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21
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Sun Q, Fu Y, Wang W. Temperature effects on hydrophobic interactions: Implications for protein unfolding. Chem Phys 2022. [DOI: 10.1016/j.chemphys.2022.111550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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22
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Kustov AV, Smirnova NL. Thermodynamics of TMU-TMU interaction in water, ethylene glycol and formamide – From pair solvophobic interaction to cluster formation. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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Pezzotti S, Sebastiani F, 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. [DOI: 10.1002/ange.202203893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Simone Pezzotti
- Department of Physical Chemistry II Ruhr University Bochum Bochum Germany
| | - Federico Sebastiani
- Department of Physical Chemistry II Ruhr University Bochum Bochum Germany
- Current affiliation: Department of Chemistry “U. Schiff” University of Florence I-50019 Sesto Fiorentino FI Italy
| | - Eliane P. Dam
- Department of Physical Chemistry II Ruhr University Bochum Bochum Germany
| | - Sashary Ramos
- Department of Physical Chemistry II Ruhr University Bochum Bochum Germany
| | - Valeria Conti Nibali
- Department of Physical Chemistry II Ruhr University Bochum Bochum Germany
- Current affiliation: Dipartimento di Scienze Matematiche e Informatiche Scienze Fisiche e Scienze della Terra (MIFT) Università di Messina 98166 Messina Italy
| | - Gerhard Schwaab
- Department of Physical Chemistry II Ruhr University Bochum Bochum Germany
| | - Martina Havenith
- Department of Physical Chemistry II Ruhr University Bochum Bochum Germany
- Department of Physics Technische Universität Dortmund 44227 Dortmund Germany
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24
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Advances of supramolecular interaction systems for improved oil recovery (IOR). Adv Colloid Interface Sci 2022; 301:102617. [PMID: 35217257 DOI: 10.1016/j.cis.2022.102617] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/17/2022] [Accepted: 02/17/2022] [Indexed: 01/07/2023]
Abstract
Improved oil recovery (IOR) includes enhanced oil recovery (EOR) and other technologies (i.e. fracturing, water injection optimization, etc.), have become important methods to increase the oil/gas production in petroleum industry. However, conventional flooding systems always encounter the problems of low efficiency, high cost and complicated synthetic procedures for harsh reservoirs conditions. In recent decades, the supramolecular interactions are introduced into IOR processes to simplify the synthetic procedures, alter their structures and properties with bespoke functionalities and responsiveness suitable for different conditions. Herein, we primarily review the fundamentals of several supramolecular interactions, including hydrophobic association, hydrogen bond, electrostatic interaction, host-guest recognition, metal-ligand coordination and dynamic covalent bond from intrinsic principles and extrinsic functions. Then, the descriptions of supramolecular interactions in IOR processes from categories and advances are focused on the following variables: polymer, surfactant, surfactant/polymer (SP) complex for EOR and viscoelasticity surfactant (VES) for clean hydraulic fracturing aspects. Finally, the field applications, challenges and prospects for supramolecular interactions in IOR processes are involved and systematically addressed. The development of supramolecular interactions can open the way toward adaptive and evolutive IOR technology, a further step towards the cost-effective production of petroleum industry.
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25
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26
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Coe MK, Evans R, Wilding NB. Density Depletion and Enhanced Fluctuations in Water near Hydrophobic Solutes: Identifying the Underlying Physics. PHYSICAL REVIEW LETTERS 2022; 128:045501. [PMID: 35148161 DOI: 10.1103/physrevlett.128.045501] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
We investigate the origin of the density depletion and enhanced density fluctuations that occur in water in the vicinity of an extended hydrophobic solute. We argue that both phenomena are remnants of the critical drying surface phase transition that occurs at liquid-vapor coexistence in the macroscopic planar limit, i.e., as the solute radius R_{s}→∞. Focusing on the density profile ρ(r) and a sensitive spatial measure of fluctuations, the local compressibility profile χ(r), we develop a scaling theory which expresses the extent of the density depletion and enhancement in compressibility in terms of R_{s}, the strength of solute-water attraction ϵ_{s}, and the deviation from liquid-vapor coexistence δμ. Testing the predictions against results of classical density functional theory for a simple solvent and grand canonical Monte Carlo simulations of a popular water model, we find that the theory provides a firm physical basis for understanding how water behaves at a hydrophobe.
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Affiliation(s)
- Mary K Coe
- H. H. Wills Physics Lab, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - Robert Evans
- H. H. Wills Physics Lab, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
| | - Nigel B Wilding
- H. H. Wills Physics Lab, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
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27
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Folberth A, Bharadwaj S, van der Vegt NFA. Small-to-large length scale transition of TMAO interaction with hydrophobic solutes. Phys Chem Chem Phys 2022; 24:2080-2087. [PMID: 35018925 DOI: 10.1039/d1cp05167a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We report the effect of trimethylamine N-oxide (TMAO) on the solvation of nonpolar solutes in water studied with molecular dynamics (MD) simulations and free-energy calculations. The simulation data indicate the occurrence of a length scale crossover in the TMAO interaction with repulsive Weeks-Chandler-Andersen (WCA) solutes: while TMAO is depleted from the hydration shell of a small WCA solute (methane) and increases the free-energy cost of solute-cavity formation, it preferentially binds to a large WCA solute (α-helical polyalanine), reducing the free-energy cost of solute-cavity formation via a surfactant-like mechanism. Significantly, we show that this surfactant-like behaviour of TMAO reinforces the solvent-mediated attraction between large WCA solutes by means of an entropic force linked to the interfacial accumulation of TMAO. Specifically, this entropic force arises from the natural tendency of adsorbed TMAO molecules to mix back into the bulk. It therefore favours solute-solute contact states that minimise the surface area exposed to the solvent and have a small overall number of TMAO molecules adsorbed. In contrast to the well-known depletion force, its effect is compensated by enthalpic solute-solvent interactions. Correspondingly, the hydrophobic association free energy of the large α-helical solutes passes through a minimum at low TMAO concentration when cohesive solute-solvent van der Waals interactions are considered. The observations reported herein are reminiscent to cosolvent effects on hydrophobic polymer coil-globule collapse free energies (Bharadwaj et al., Commun. Chem. 2020, 3, 165) and may be of general significance in systems whose properties are determined by hydrophobic self-assembly.
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Affiliation(s)
- Angelina Folberth
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany.
| | - Swaminath Bharadwaj
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany.
| | - Nico F A van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, 64287 Darmstadt, Germany.
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28
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van Gils JHM, Gogishvili D, van Eck J, Bouwmeester R, van Dijk E, Abeln S. How sticky are our proteins? Quantifying hydrophobicity of the human proteome. BIOINFORMATICS ADVANCES 2022; 2:vbac002. [PMID: 36699344 PMCID: PMC9710682 DOI: 10.1093/bioadv/vbac002] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/19/2021] [Accepted: 01/24/2022] [Indexed: 01/28/2023]
Abstract
Summary Proteins tend to bury hydrophobic residues inside their core during the folding process to provide stability to the protein structure and to prevent aggregation. Nevertheless, proteins do expose some 'sticky' hydrophobic residues to the solvent. These residues can play an important functional role, e.g. in protein-protein and membrane interactions. Here, we first investigate how hydrophobic protein surfaces are by providing three measures for surface hydrophobicity: the total hydrophobic surface area, the relative hydrophobic surface area and-using our MolPatch method-the largest hydrophobic patch. Secondly, we analyze how difficult it is to predict these measures from sequence: by adapting solvent accessibility predictions from NetSurfP2.0, we obtain well-performing prediction methods for the THSA and RHSA, while predicting LHP is more challenging. Finally, we analyze implications of exposed hydrophobic surfaces: we show that hydrophobic proteins typically have low expression, suggesting cells avoid an overabundance of sticky proteins. Availability and implementation The data underlying this article are available in GitHub at https://github.com/ibivu/hydrophobic_patches. Supplementary information Supplementary data are available at Bioinformatics Advances online.
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Affiliation(s)
- Juami Hermine Mariama van Gils
- Computer Science Department, Center for Integrative Bioinformatics (IBIVU), Vrije Universiteit Amsterdam, 1081 HV Noord-Holland, The Netherlands,To whom correspondence should be addressed. or
| | - Dea Gogishvili
- Computer Science Department, Center for Integrative Bioinformatics (IBIVU), Vrije Universiteit Amsterdam, 1081 HV Noord-Holland, The Netherlands
| | - Jan van Eck
- Computer Science Department, Center for Integrative Bioinformatics (IBIVU), Vrije Universiteit Amsterdam, 1081 HV Noord-Holland, The Netherlands
| | - Robbin Bouwmeester
- Computer Science Department, Center for Integrative Bioinformatics (IBIVU), Vrije Universiteit Amsterdam, 1081 HV Noord-Holland, The Netherlands
| | - Erik van Dijk
- Computer Science Department, Center for Integrative Bioinformatics (IBIVU), Vrije Universiteit Amsterdam, 1081 HV Noord-Holland, The Netherlands
| | - Sanne Abeln
- Computer Science Department, Center for Integrative Bioinformatics (IBIVU), Vrije Universiteit Amsterdam, 1081 HV Noord-Holland, The Netherlands,To whom correspondence should be addressed. or
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29
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Moon H, Collanton RP, Monroe JI, Casey TM, Shell MS, Han S, Scott SL. Evidence for Entropically Controlled Interfacial Hydration in Mesoporous Organosilicas. J Am Chem Soc 2022; 144:1766-1777. [PMID: 35041412 DOI: 10.1021/jacs.1c11342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
At aqueous interfaces, the distribution and dynamics of adsorbates are modulated by the behavior of interfacial water. Hydration of a hydrophobic surface can store entropy via the ordering of interfacial water, which contributes to the Gibbs energy of solute binding. However, there is little experimental evidence for the existence of such entropic reservoirs, and virtually no precedent for their rational design in systems involving extended interfaces. In this study, two series of mesoporous silicas were modified in distinct ways: (1) progressively deeper thermal dehydroxylation, via condensation of surface silanols, and (2) increasing incorporation of nonpolar organic linkers into the silica framework. Both approaches result in decreasing average surface polarity, manifested in a blue-shift in the fluorescence of an adsorbed dye. For the inorganic silicas, hydrogen-bonding of water becomes less extensive as the number of surface silanols decreases. Overhauser dynamic nuclear polarization (ODNP) relaxometry indicates enhanced surface water diffusivity, reflecting a loss of enthalpic hydration. In contrast, organosilicas show a monotonic decrease in surface water diffusivity with decreasing polarity, reflecting enhanced hydrophobic hydration. Molecular dynamics simulations predict increased tetrahedrality of interfacial water for the organosilicas, implying increased ordering near the nm-size organic domains (relative to inorganic silicas, which necessarily lack such domains). These findings validate the prediction that hydrophobic hydration at interfaces is controlled by the microscopic length scale of the hydrophobic regions. They further suggest that the hydration thermodynamics of structurally heterogeneous silica surfaces can be tuned to promote adsorption, which in turn tunes the selectivity in catalytic reactions.
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Affiliation(s)
- Hyunjin Moon
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | - Ryan P Collanton
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | - Jacob I Monroe
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | - Thomas M Casey
- Department of Chemistry & 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
| | - Songi Han
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States.,Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106-9510, United States
| | - Susannah L Scott
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States.,Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106-9510, United States
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30
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Bogunia M, Liwo A, Czaplewski C, Makowska J, Giełdoń A, Makowski M. Influence of Temperature and Salt Concentration on the Hydrophobic Interactions of Adamantane and Hexane. J Phys Chem B 2022; 126:634-642. [PMID: 35025490 PMCID: PMC8802301 DOI: 10.1021/acs.jpcb.1c09860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
One of the definitions
of hydrophobic interactions is the aggregation
of nonpolar particles in a polar solvent, such as water. While this
phenomenon appears to be very simple, it is crucial for many complex
processes, such as protein folding, to take place. In this work, the
hydrophobic association of adamantane and hexane at various temperatures
and ionic strengths was studied using molecular dynamics simulations
with the AMBER 16.0 program and the GAFF force field. The potentials
of mean force of hydrophobic dimer formation, as well as the excess
free energy, excess energy, excess entropy, and excess heat capacity
corresponding to the formation of the contact minimum, were determined
and analyzed. For both systems, the depth of the contact minimum in
the potential of mean force was found to increase with both temperature
and ionic strength. The excess heat capacity of the association at
the contact minimum and T = 298 K was found to be
negative and to decrease, while the excess entropy and energy were
found to be positive and to increase for both systems, the changes
being more pronounced for the hexane dimer. The excess heat capacity
is also greater in absolute value for the hexane dimer.
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Affiliation(s)
- Małgorzata Bogunia
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, Gdańsk 80-308, Poland
| | - Adam Liwo
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, Gdańsk 80-308, Poland
| | - Cezary Czaplewski
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, Gdańsk 80-308, Poland
| | - Joanna Makowska
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, Gdańsk 80-308, Poland
| | - Artur Giełdoń
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, Gdańsk 80-308, Poland
| | - Mariusz Makowski
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, Gdańsk 80-308, Poland
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Pitz ME, Nukovic AM, Elpers MA, Alexander-Bryant AA. Factors Affecting Secondary and Supramolecular Structures of Self-Assembling Peptide Nanocarriers. Macromol Biosci 2021; 22:e2100347. [PMID: 34800001 DOI: 10.1002/mabi.202100347] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/19/2021] [Indexed: 01/12/2023]
Abstract
Self-assembling peptides are a popular vector for therapeutic cargo delivery due to their versatility, tunability, and biocompatibility. Accurately predicting secondary and supramolecular structures of self-assembling peptides is essential for de novo peptide design. However, computational modeling of such assemblies is not yet able to accurately predict structure formation for many peptide sequences. This review identifies patterns in literature between secondary and supramolecular structures, primary sequences, and applications to provide a guide for informed peptide design. An overview of peptide structures, their applications as nanocarriers, and analytical methods for characterizing secondary and supramolecular structure is examined. A top-down approach is then used to identify trends between peptide sequence and assembly structure from the current literature, including an analysis of the drivers at work, such as local and nonlocal sequence effects and solution conditions.
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Affiliation(s)
- Megan E Pitz
- Department of Bioengineering, 301 Rhodes Research Center, Clemson University, Clemson, SC, 29634-0905, USA
| | - Alexandra M Nukovic
- Department of Bioengineering, 301 Rhodes Research Center, Clemson University, Clemson, SC, 29634-0905, USA
| | - Margaret A Elpers
- Department of Bioengineering, 301 Rhodes Research Center, Clemson University, Clemson, SC, 29634-0905, USA
| | - Angela A Alexander-Bryant
- Department of Bioengineering, 301 Rhodes Research Center, Clemson University, Clemson, SC, 29634-0905, USA
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32
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33
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Effects of hydrophobic solute on water normal modes. Chem Phys 2021. [DOI: 10.1016/j.chemphys.2021.111303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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34
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Physicochemical characterisation of kafirins extracted from sorghum grain and dried distillers grain with solubles related to their biomaterial functionality. Sci Rep 2021; 11:15204. [PMID: 34312467 PMCID: PMC8313537 DOI: 10.1038/s41598-021-94718-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 07/15/2021] [Indexed: 11/09/2022] Open
Abstract
Kafirin, the hydrophobic prolamin storage protein in sorghum grain is enriched when the grain is used for bioethanol production to give dried distillers grain with solubles (DGGS) as a by-product. There is great interest in DDGS kafirin as a new source for biomaterials. There is however a lack of fundamental understanding of how the physicochemical properties of DDGS kafirin having been exposed to the high temperature conditions during ethanol production, compare to kafirin made directly from the grain. An understanding of these properties is required to catalyse the utilisation of DDGS kafirin for biomaterial applications. The aim of this study was to extract kafirin directly from sorghum grain and from DDGS derived from the same grain and, then perform a comparative investigation of the physicochemical properties of these kafirins in terms of: polypeptide profile by sodium-dodecyl sulphate polyacrylamide gel electrophoresis; secondary structure by Fourier transform infra-red spectroscopy and x-ray diffraction, self-assembly behaviour by small-angle x-ray scattering, surface morphology by scanning electron microscopy and surface chemical properties by energy dispersive x-ray spectroscopy. DDGS kafirin was found to have very similar polypeptide profile as grain kafirin but contained altered secondary structure with increased levels of β-sheets. The structure morphology showed surface fractals and surface elemental composition suggesting enhanced reactivity with possibility to endow interfacial wettability. These properties of DDGS kafirin may provide it with unique functionality and thus open up opportunities for it to be used as a novel food grade biomaterial.
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Li NK, Xie Y, Yingling YG. Insights into Structure and Aggregation Behavior of Elastin-like Polypeptide Coacervates: All-Atom Molecular Dynamics Simulations. J Phys Chem B 2021; 125:8627-8635. [PMID: 34288691 DOI: 10.1021/acs.jpcb.1c02822] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The stimuli-responsive character of elastin-like polypeptides (ELP) has led to their use in a wide range of applications. The temperature-triggered aggregation, or LCST behavior, of ELPs is a complex and multistep phenomenon, which proposed to include the structural transitions, loss of hydrophobic hydration, expulsion of water molecules and physical association of chains. Thus, the origin and detailed mechanism of LCST in ELPs is difficult to elucidate. Here, to gain insights into structure and dynamics of coacervates, we performed all-atom molecular dynamics simulations of 27 90-mer ELPs in explicit water at 350 K. Two sequences, poly(VGPVG)18 and poly(VPGVG)18, were examined due to their experimentally observed differences in thermal hysteresis albeit identical overall composition but different arrangement of amino acids. The simulation results indicate that surface hydrophobicity of poly(VGPVG) aggregate is less than that of the poly(VPGVG) aggregate, and there are marked changes in torsion angles and the propensities of secondary structural motifs during the aggregation process. Moreover, there are significant differences between structure of a single polypeptide in water and structure within the aggregate. Overall, the aggregation process is driven by the formation of peptide-peptide interactions whereas the average hydration of peptides remains almost the same between dissolved and aggregated states. Even though the aggregation is driven by the hydrophobic interactions, ELP coacervate has no hydrophobic core and contains many water molecules. Overall, our findings provide an insight into the sequence-dependent structure of coacervates and molecular behavior of individual peptides during aggregation.
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Affiliation(s)
- Nan K Li
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Yuxin Xie
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Yaroslava G Yingling
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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36
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Sun Q, Wang W, Cui S. Directional nature of hydrophobic interactions: Implications for the mechanism of molecular recognition. Chem Phys 2021. [DOI: 10.1016/j.chemphys.2021.111200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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37
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Noriega R. Measuring the Multiscale Dynamics, Structure, and Function of Biomolecules at Interfaces. J Phys Chem B 2021; 125:5667-5675. [PMID: 34042455 DOI: 10.1021/acs.jpcb.1c01546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The individual and collective structure and properties of biomolecules can change dramatically when they are localized at an interface. However, the small spatial extent of interfacial regions poses challenges to the detailed characterization of multiscale processes that dictate the structure and function of large biological units such as peptides, proteins, or nucleic acids. This Perspective surveys a broad set of tools that provide new opportunities to probe complex, dynamic interfaces across the vast range of temporal regimes that connect molecular-scale events to macroscopic observables. An emphasis is placed on the integration over multiple time scales, the use of complementary techniques, and the incorporation of external stimuli to control interfacial properties with spatial, temporal, and chemical specificity.
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Affiliation(s)
- Rodrigo Noriega
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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38
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Corrigan RA, Qi G, Thiel AC, Lynn JR, Walker BD, Casavant TL, Lagardere L, Piquemal JP, Ponder JW, Ren P, Schnieders MJ. Implicit Solvents for the Polarizable Atomic Multipole AMOEBA Force Field. J Chem Theory Comput 2021; 17:2323-2341. [PMID: 33769814 DOI: 10.1021/acs.jctc.0c01286] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Computational protein design, ab initio protein/RNA folding, and protein-ligand screening can be too computationally demanding for explicit treatment of solvent. For these applications, implicit solvent offers a compelling alternative, which we describe here for the polarizable atomic multipole AMOEBA force field based on three treatments of continuum electrostatics: numerical solutions to the nonlinear and linearized versions of the Poisson-Boltzmann equation (PBE), the domain-decomposition conductor-like screening model (ddCOSMO) approximation to the PBE, and the analytic generalized Kirkwood (GK) approximation. The continuum electrostatics models are combined with a nonpolar estimator based on novel cavitation and dispersion terms. Electrostatic model parameters are numerically optimized using a least-squares style target function based on a library of 103 small-molecule solvation free energy differences. Mean signed errors for the adaptive Poisson-Boltzmann solver (APBS), ddCOSMO, and GK models are 0.05, 0.00, and 0.00 kcal/mol, respectively, while the mean unsigned errors are 0.70, 0.63, and 0.58 kcal/mol, respectively. Validation of the electrostatic response of the resulting implicit solvents, which are available in the Tinker (or Tinker-HP), OpenMM, and Force Field X software packages, is based on comparisons to explicit solvent simulations for a series of proteins and nucleic acids. Overall, the emergence of performative implicit solvent models for polarizable force fields opens the door to their use for folding and design applications.
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Affiliation(s)
- Rae A Corrigan
- Roy J Carver Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Guowei Qi
- Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Andrew C Thiel
- Roy J Carver Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Jack R Lynn
- Roy J Carver Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Brandon D Walker
- Department of Biomedical Engineering, University of Texas in Austin, Austin, Texas 78712, United States
| | - Thomas L Casavant
- Roy J Carver Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Louis Lagardere
- Department of Chemistry, Sorbonne Université, F-75005 Paris, France
| | | | - Jay W Ponder
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Pengyu Ren
- Department of Biomedical Engineering, University of Texas in Austin, Austin, Texas 78712, United States
| | - Michael J Schnieders
- Roy J Carver Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, United States.,Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, United States
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39
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Size dependence of hydrophobic hydration at electrified gold/water interfaces. Proc Natl Acad Sci U S A 2021; 118:2023867118. [PMID: 33876767 DOI: 10.1073/pnas.2023867118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hydrophobic hydration at metal/water interfaces actively contributes to the energetics of electrochemical reactions, e.g. [Formula: see text] and [Formula: see text] reduction, where small hydrophobic molecules are involved. In this work, constant applied potential molecular dynamics is employed to study hydrophobic hydration at a gold/water interface. We propose an adaptation of the Lum-Chandler-Weeks (LCW) theory to describe the free energy of hydrophobic hydration at the interface as a function of solute size and applied voltage. Based on this model we are able to predict the free energy cost of cavity formation at the interface directly from the free energy cost in the bulk plus an interface-dependent correction term. The interfacial water network contributes significantly to the free energy, yielding a preference for outer-sphere adsorption at the gold surface for ideal hydrophobes. We predict an accumulation of small hydrophobic solutes of sizes comparable to CO or [Formula: see text], while the free energy cost to hydrate larger hydrophobes, above 2.5-Å radius, is shown to be greater at the interface than in the bulk. Interestingly, the transition from the volume dominated to the surface dominated regimes predicted by the LCW theory in the bulk is also found to take place for hydrophobes at the Au/water interface but occurs at smaller cavity radii. By applying the adapted LCW theory to a simple model addition reaction, we illustrate some implications of our findings for electrochemical reactions.
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40
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Verde AR, de Oca JMM, Accordino SR, Alarcón LM, Appignanesi GA. Structural aspects of an energy-based water classification index and the structure-dynamics link in glassy relaxation. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:47. [PMID: 33783648 DOI: 10.1140/epje/s10189-021-00057-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
An energy-based structural indicator for water, [Formula: see text], has been recently introduced by our group. In turn, in this work we aim at: (1) demonstrating that [Formula: see text] is indeed able to correctly classify water molecules between locally structured tetrahedral (T) and locally distorted (D) ones, circumventing the usual problem of certain previous indicators of overestimating the distorted state; (2) correlating [Formula: see text] with dynamic propensity, a measure of the molecular mobility tendency, in order to seek for the existence of a connection between structure and dynamics within the supercooled regime. More specifically, in the first part of this work we will show that [Formula: see text] accurately discriminates between merely thermally deformed local molecular arrangements and truly distorted molecules (defects). This fact will be made evident not only from radial distribution function results but also from the dynamic propensity distributions of the different kinds of molecules. In turn, we shall devote the second part of this work to finding correlations between T and D molecules with low- and high-dynamic-propensity molecules, respectively, thus revealing the existence of a link between local structure and dynamics, while also making evident the dominant role of the D molecules (defects) in the structural relaxation. Moreover, the availability of a proper molecular classification technique will enable us to study the timescale of such influence of structure on dynamics by defining a modified dynamic propensity measure and by applying it to the structured and unstructured water molecular states.
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Affiliation(s)
- Alejandro R Verde
- Departamento de Química, INQUISUR, Universidad Nacional del Sur (UNS)-CONICET, Avenida Alem 1253, 8000, Bahía Blanca, Argentina
| | - Joan Manuel Montes de Oca
- Departamento de Química, INQUISUR, Universidad Nacional del Sur (UNS)-CONICET, Avenida Alem 1253, 8000, Bahía Blanca, Argentina
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA
| | - Sebastián R Accordino
- Departamento de Química, INQUISUR, Universidad Nacional del Sur (UNS)-CONICET, Avenida Alem 1253, 8000, Bahía Blanca, Argentina
| | - Laureano M Alarcón
- Departamento de Química, INQUISUR, Universidad Nacional del Sur (UNS)-CONICET, Avenida Alem 1253, 8000, Bahía Blanca, Argentina
| | - Gustavo A Appignanesi
- Departamento de Química, INQUISUR, Universidad Nacional del Sur (UNS)-CONICET, Avenida Alem 1253, 8000, Bahía Blanca, Argentina.
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41
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Priyadarsini A, Mallik BS. Insignificant Effect of Temperature on the Structure and Angular Jumps of Water near a Hydrophobic Cation. ACS OMEGA 2021; 6:8356-8364. [PMID: 33817496 PMCID: PMC8015100 DOI: 10.1021/acsomega.1c00091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/15/2021] [Indexed: 05/12/2023]
Abstract
The ambiguity in the behavior of water molecules around hydrophobic solutes is a matter of interest for many studies. Motivated by the earlier results on the dynamics of water molecules around tetramethylammonium (TMA) cation, we present the effect of temperature on the structure and angular jumps of water due to hydrophobicity using first principles molecular dynamics simulations. The average intermolecular distance between the central oxygen and four nearest neighbors is found to be the highest for water molecules in the solvation shell of TMA at 400 K, followed by the same at 330 K. The hydrogen bond (HB) donor-acceptor count, HB per water molecule, and tetrahedral order parameter suggests the loss of tetrahedrality in the solvation shell. Elevated temperature affects the tetrahedral parameter in local regions. The HB jump mechanism is studied for methyl hydrogen and water molecules in the solvation shell. Observations hint at the presence of dangling water molecules in the vicinity of the hydrophobic cation, and no evidence is found for the enhanced structural ordering of nearby water molecules.
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42
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Cerdeiriña CA, González-Salgado D. Temperature, Pressure, and Length-Scale Dependence of Solvation in Water-like Solvents. I. Small Solvophobic Solutes. J Phys Chem B 2020; 125:297-306. [DOI: 10.1021/acs.jpcb.0c09569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Claudio A. Cerdeiriña
- Departamento de Física Aplicada, Universidad de Vigo, Campus del Agua, Ourense 32004, Spain
| | - Diego González-Salgado
- Departamento de Física Aplicada, Universidad de Vigo, Campus del Agua, Ourense 32004, Spain
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43
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Tamoliu Nas K, Galamba N. Protein Denaturation, Zero Entropy Temperature, and the Structure of Water around Hydrophobic and Amphiphilic Solutes. J Phys Chem B 2020; 124:10994-11006. [PMID: 33201713 DOI: 10.1021/acs.jpcb.0c08055] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The hydrophobic effect plays a key role in many chemical and biological processes, including protein folding. Nonetheless, a comprehensive picture of the effect of temperature on hydrophobic hydration and protein denaturation remains elusive. Here, we study the effect of temperature on the hydration of model hydrophobic and amphiphilic solutes, through molecular dynamics, aiming at getting insight on the singular behavior of water, concerning the zero-entropy temperature, TS, and entropy convergence, TS*, also observed for some proteins, upon denaturation. We show that, similar to hydrocarbons, polar amphiphilic solutes exhibit a TS, although strongly dependent on solute-water interactions, opposite to hydrocarbons. Further, the temperature dependence of the hydration entropy, normalized by the solvent accessible surface area, is shown to be nearly solute size independent for hydrophobic but not for amphiphilic solutes, for similar reasons. These results are further discussed in the light of information theory (IT) and the structure of water around hydrophobic groups. The latter shows that the tetrahedral enhancement of some water molecules around hydrophobic groups, associated with the reduction of water defects, leads to the strengthening of the weakest hydrogen bonds, relative to bulk water. In addition, a larger tetrahedrality is found in low density water populations, demonstrating that pure water has encoded structural information, similar to that associated with hydrophobic hydration. The reversal of the hydration entropy dependence on the solute size, above TS*, is also analyzed and shown to be associated with a greater loss of water molecules exhibiting enhanced orientational order, in the coordination sphere of large solutes. Finally, the source of the differences between Kauzmann's "hydrocarbon model" on protein denaturation and hydrophobic hydration is discussed, with relatively large amphiphilic hydrocarbons seemingly displaying a more similar behavior to some globular proteins than aliphatic hydrocarbons.
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Affiliation(s)
- Kazimieras Tamoliu Nas
- Centre of Chemistry and Biochemistry and Biosystems and Integrative Sciences Institute, Faculty of Sciences of the University of Lisbon, C8, Campo Grande, 1749-016 Lisbon, Portugal
| | - Nuno Galamba
- Centre of Chemistry and Biochemistry and Biosystems and Integrative Sciences Institute, Faculty of Sciences of the University of Lisbon, C8, Campo Grande, 1749-016 Lisbon, Portugal
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44
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45
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Elias RD, Ma W, Ghirlando R, Schwieters CD, Reddy VS, Deshmukh L. Proline-rich domain of human ALIX contains multiple TSG101-UEV interaction sites and forms phosphorylation-mediated reversible amyloids. Proc Natl Acad Sci U S A 2020; 117:24274-24284. [PMID: 32917811 PMCID: PMC7533887 DOI: 10.1073/pnas.2010635117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Proline-rich domains (PRDs) are among the most prevalent signaling modules of eukaryotes but often unexplored by biophysical techniques as their heterologous recombinant expression poses significant difficulties. Using a "divide-and-conquer" approach, we present a detailed investigation of a PRD (166 residues; ∼30% prolines) belonging to a human protein ALIX, a versatile adaptor protein involved in essential cellular processes including ESCRT-mediated membrane remodeling, cell adhesion, and apoptosis. In solution, the N-terminal fragment of ALIX-PRD is dynamically disordered. It contains three tandem sequentially similar proline-rich motifs that compete for a single binding site on its signaling partner, TSG101-UEV, as evidenced by heteronuclear NMR spectroscopy. Global fitting of relaxation dispersion data, measured as a function of TSG101-UEV concentration, allowed precise quantitation of these interactions. In contrast to the soluble N-terminal portion, the C-terminal tyrosine-rich fragment of ALIX-PRD forms amyloid fibrils and viscous gels validated using dye-binding assays with amyloid-specific probes, congo red and thioflavin T (ThT), and visualized by transmission electron microscopy. Remarkably, fibrils dissolve at low temperatures (2 to 6 °C) or upon hyperphosphorylation with Src kinase. Aggregation kinetics monitored by ThT fluorescence shows that charge repulsion dictates phosphorylation-mediated fibril dissolution and that the hydrophobic effect drives fibril formation. These data illuminate the mechanistic interplay between interactions of ALIX-PRD with TSG101-UEV and polymerization of ALIX-PRD and its central role in regulating ALIX function. This study also demonstrates the broad functional repertoires of PRDs and uncovers the impact of posttranslational modifications in the modulation of reversible amyloids.
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Affiliation(s)
- Ruben D Elias
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
| | - Wen Ma
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Charles D Schwieters
- Division of Computational Biosciences, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892
| | - Vijay S Reddy
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Lalit Deshmukh
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093;
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46
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Reddy KD, Biswas R. Theoretical spectroscopy of isotopically dilute water and hydrophobicity. J Chem Phys 2020; 153:094501. [DOI: 10.1063/5.0018401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Affiliation(s)
- Kambham Devendra Reddy
- Department of Chemistry and Center for Atomic, Molecular and Optical Sciences & Technologies, Indian Institute of Technology Tirupati, Yerpedu 517619, Andhra Pradesh, India
| | - Rajib Biswas
- Department of Chemistry and Center for Atomic, Molecular and Optical Sciences & Technologies, Indian Institute of Technology Tirupati, Yerpedu 517619, Andhra Pradesh, India
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47
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Baul U, Bley M, Dzubiella J. Thermal Compaction of Disordered and Elastin-like Polypeptides: A Temperature-Dependent, Sequence-Specific Coarse-Grained Simulation Model. Biomacromolecules 2020; 21:3523-3538. [DOI: 10.1021/acs.biomac.0c00546] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Upayan Baul
- Applied Theoretical Physics—Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Strasse 3, D-79104 Freiburg, Germany
| | - Michael Bley
- Applied Theoretical Physics—Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Strasse 3, D-79104 Freiburg, Germany
| | - Joachim Dzubiella
- Applied Theoretical Physics—Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Strasse 3, D-79104 Freiburg, Germany
- Cluster of Excellence livMatS@FIT—Freiburg Center for Interactive Materials and Bioinspired Technologies, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee 105, D-79110 Freiburg, Germany
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48
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Conti Nibali V, Pezzotti S, Sebastiani F, Galimberti DR, Schwaab G, Heyden M, Gaigeot MP, Havenith M. Wrapping Up Hydrophobic Hydration: Locality Matters. J Phys Chem Lett 2020; 11:4809-4816. [PMID: 32459100 PMCID: PMC8253475 DOI: 10.1021/acs.jpclett.0c00846] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 05/27/2020] [Indexed: 05/17/2023]
Abstract
Water, being the universal solvent, acts as a competing agent in fundamental processes, such as folding, aggregation or biomolecular recognition. A molecular understanding of hydrophobic hydration is of central importance to understanding the subtle free energy differences, which dictate function. Ab initio and classical molecular dynamics simulations yield two distinct hydration water populations in the hydration shell of solvated tert-butanol noted as "HB-wrap" and "HB-hydration2bulk". The experimentally observed hydration water spectrum can be dissected into two modes, centered at 164 and 195 cm-1. By comparison to the simulations, these two bands are attributed to the "HB-wrap" and "HB-hydration2bulk" populations, respectively. We derive a quantitative correlation between the population in each of these two local water coordination motifs and the temperature dependence of the solvation entropy. The crossover from entropy to enthalpy dominated solvation at elevated temperatures, as predicted by theory and observed experimentally, can be rationalized in terms of the distinct temperature stability and thermodynamic signatures of "HB-wrap" and "HB-hydration2bulk".
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Affiliation(s)
- V. Conti Nibali
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
| | - S. Pezzotti
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
- LAMBE
CNRS UMR8587, Université d’Evry
val d’Essonne & Université Paris-Saclay, 91000 Evry, France
| | - F. Sebastiani
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
| | - D. R. Galimberti
- LAMBE
CNRS UMR8587, Université d’Evry
val d’Essonne & Université Paris-Saclay, 91000 Evry, France
| | - G. Schwaab
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
| | - M. Heyden
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - M.-P. Gaigeot
- LAMBE
CNRS UMR8587, Université d’Evry
val d’Essonne & Université Paris-Saclay, 91000 Evry, France
| | - M. Havenith
- Department of Physical Chemistry II, Ruhr University Bochum, 44780 Bochum, Germany
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49
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Role of molecular architecture in the modulation of hydrophobic interactions. Curr Opin Colloid Interface Sci 2020. [DOI: 10.1016/j.cocis.2019.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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The hydrophobic effect characterises the thermodynamic signature of amyloid fibril growth. PLoS Comput Biol 2020; 16:e1007767. [PMID: 32365068 PMCID: PMC7282669 DOI: 10.1371/journal.pcbi.1007767] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 06/09/2020] [Accepted: 03/02/2020] [Indexed: 11/19/2022] Open
Abstract
Many proteins have the potential to aggregate into amyloid fibrils, protein polymers associated with a wide range of human disorders such as Alzheimer’s and Parkinson’s disease. The thermodynamic stability of amyloid fibrils, in contrast to that of folded proteins, is not well understood: the balance between entropic and enthalpic terms, including the chain entropy and the hydrophobic effect, are poorly characterised. Using a combination of theory, in vitro experiments, simulations of a coarse-grained protein model and meta-data analysis, we delineate the enthalpic and entropic contributions that dominate amyloid fibril elongation. Our prediction of a characteristic temperature-dependent enthalpic signature is confirmed by the performed calorimetric experiments and a meta-analysis over published data. From these results we are able to define the necessary conditions to observe cold denaturation of amyloid fibrils. Overall, we show that amyloid fibril elongation is associated with a negative heat capacity, the magnitude of which correlates closely with the hydrophobic surface area that is buried upon fibril formation, highlighting the importance of hydrophobicity for fibril stability. Most proteins fold in the cell into stable, compact structures. Nevertheless, many proteins also have the ability to stick together, forming long fibrillar structures that are associated with a wide range of human disorders including Alzheimer’s and Parkinson’s disease. The exact nature of the amyloid-causing stickiness is not well understood, nevertheless amyloid fibrils show some very specific thermodynamic characteristics. Some fibrils even destabilise at low temperatures. In this work we translate hydrophobic theory previously used to model protein folding to fibril formation. We combine this theory with experimental measurements, simulations and meta-data analysis of different types of fibrils. This allowed us to unravel the nature of the stickiness in amyloid fibrils by observing the effect of temperature changes, specifically at low temperatures, on hydrophobicity.
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