51
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Ramirez LM, Shekhtman A, Pande J. Hydrophobic residues of melittin mediate its binding to αA-crystallin. Protein Sci 2019; 29:572-588. [PMID: 31762096 DOI: 10.1002/pro.3792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 01/01/2023]
Abstract
The molecular chaperone αA-crystallin, mainly localized in the human ocular lens, is believed to protect the lens from opacification and cataract, by suppressing the aggregation of the other lens proteins. The present study provides structural and thermodynamic insights into the ability of human αA-crystallin (HAA) to bind to its partially unfolded clients in the lens, using a small peptide, melittin from bee venom, as a model client. We characterized the thermodynamic parameters of the binding process between melittin and HAA through isothermal titration calorimetry (ITC), and found the binding to be endothermic and entropy-driven. We identified the amino acids in melittin important for binding to HAA by saturation-transfer difference (STD) nuclear magnetic resonance (NMR) experiments, and analysis of NMR line broadening upon titration of melittin with HAA. Our results suggest that hydrophobic residues Ile17 and Ile20 on the C-terminal region of melittin are in close contact with HAA in the melittin-HAA complex. Information obtained from NMR experiments was used to generate structural models of the melittin-HAA complex by molecular docking with high-ambiguity driven docking (HADDOCK). Structural models of the melittin-HAA complex reveal important principles underlying the interaction of HAA with its clients.
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Affiliation(s)
- Lisa M Ramirez
- Department of Chemistry, University at Albany, State University of New York, Albany, New York
| | - Alexander Shekhtman
- Department of Chemistry, University at Albany, State University of New York, Albany, New York
| | - Jayanti Pande
- Department of Chemistry, University at Albany, State University of New York, Albany, New York
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52
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Sharma T, Harioudh MK, Kuldeep J, Kumar S, Banerjee D, Ghosh JK, Siddiqi MI. Identification of Potential Inhibitors of Cathepsin-B using Shape & Pharmacophore-based Virtual Screening, Molecular Docking and Explicit Water Thermodynamics. Mol Inform 2019; 39:e1900023. [PMID: 31648416 DOI: 10.1002/minf.201900023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 09/18/2019] [Indexed: 12/12/2022]
Abstract
Lysosome has been long understood as a vital digestive organelle. Increasing reports indicate that the lysosome also plays a crucial role in the pathogenesis of a variety of neurodegenerative diseases, including Huntington's disease, Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. Abnormal protein degradation and deposition stimulated by lysosomal dysfunction may cause age-related neurodegeneration. Enormous efforts have been devoted to the development of effective therapeutics against Alzheimer's disease, the most debilitating neurodegenerative disease. Endopeptidase activity of the Cathepsin-B is associated with the pathological processes. Work presented here focuses on identification of new inhibitors against Cathepsin-B protein using diverse computational approaches together. The inhibitors identified were further tested for in-vitro activity using enzyme based assay method. The identified inhibitors provided interesting understanding on how the water thermodynamic properties along with hydrophobic, steric, electronic, and structural requirements contribute to cathepsin-B inhibitory activity. These water thermodynamic studies, may further be used in computer aided drug discovery pipeline to design and predict more potent derivatives of various scaffolds as cathepsin-B inhibitors.
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Affiliation(s)
- Tanuj Sharma
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Munesh Kumar Harioudh
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Jitendra Kuldeep
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Sushil Kumar
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Dibyendu Banerjee
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Drug Research Institute, Campus, Lucknow, 226031, India
| | - Jimut Kanti Ghosh
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Drug Research Institute, Campus, Lucknow, 226031, India
| | - Mohammad Imran Siddiqi
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Drug Research Institute, Campus, Lucknow, 226031, India
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53
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He P, Sarkar S, Gallicchio E, Kurtzman T, Wickstrom L. Role of Displacing Confined Solvent in the Conformational Equilibrium of β-Cyclodextrin. J Phys Chem B 2019; 123:8378-8386. [PMID: 31509409 DOI: 10.1021/acs.jpcb.9b07028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study investigates the role of hydration and its relationship to the conformational equilibrium of the host molecule β-cyclodextrin. Molecular dynamics simulations indicate that the unbound β-cyclodextrin exhibits two state behavior in explicit solvent due to the opening and closing of its cavity. In implicit solvent, these transitions are not observed, and there is one dominant conformation of β-cyclodextrin with an open cavity. Based on these observations, we investigate the hypothesis that the expulsion of thermodynamically unfavorable water molecules into the bulk plays an important role in controlling the accessibility of the closed macrostate at room temperature. We compare the results of the molecular mechanics analytical generalized Born plus nonpolar solvation approach to those obtained through grid inhomogeneous solvation theory analysis with explicit solvation to elucidate the thermodynamic forces at play. The work illustrates the use of continuum solvent models to tease out solvation effects related to the inhomogeneity and the molecular nature of water and demonstrates the key role of the thermodynamics of enclosed hydration in driving the conformational equilibrium of molecules in solution.
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Affiliation(s)
- Peng He
- Center for Biophysics & Computational Biology/ICMS, Department of Chemistry , Temple University , Philadelphia , Pennsylvania 19122 , United States
| | - Sheila Sarkar
- Department of Science , Borough of Manhattan Community College, The City University of New York , New York , New York 10007 , United States
| | - Emilio Gallicchio
- Department of Chemistry , Brooklyn College, The City University of New York , Brooklyn , New York 11210 , United States.,Ph.D. Programs in Chemistry & Biochemistry , The Graduate Center of the City University of New York , 365 Fifth Avenue , New York , New York 10016 , United States
| | - Tom Kurtzman
- Department of Chemistry , Lehman College, The City University of New York , Bronx , New York 10468 , United States.,Ph.D. Programs in Chemistry & Biochemistry , The Graduate Center of the City University of New York , 365 Fifth Avenue , New York , New York 10016 , United States
| | - Lauren Wickstrom
- Department of Science , Borough of Manhattan Community College, The City University of New York , New York , New York 10007 , United States
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54
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Pal RK, Gadhiya S, Ramsey S, Cordone P, Wickstrom L, Harding WW, Kurtzman T, Gallicchio E. Inclusion of enclosed hydration effects in the binding free energy estimation of dopamine D3 receptor complexes. PLoS One 2019; 14:e0222902. [PMID: 31568493 PMCID: PMC6768453 DOI: 10.1371/journal.pone.0222902] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 08/30/2019] [Indexed: 01/04/2023] Open
Abstract
Confined hydration and conformational flexibility are some of the challenges encountered for the rational design of selective antagonists of G-protein coupled receptors. We present a set of C3-substituted (-)-stepholidine derivatives as potent binders of the dopamine D3 receptor. The compounds are characterized biochemically, as well as by computer modeling using a novel molecular dynamics-based alchemical binding free energy approach which incorporates the effect of the displacement of enclosed water molecules from the binding site. The free energy of displacement of specific hydration sites is obtained using the Hydration Site Analysis method with explicit solvation. This work underscores the critical role of confined hydration and conformational reorganization in the molecular recognition mechanism of dopamine receptors and illustrates the potential of binding free energy models to represent these key phenomena.
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Affiliation(s)
- Rajat Kumar Pal
- Department of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, NY 11210, United States of America
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
| | - Satishkumar Gadhiya
- PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
- Department of Chemistry, Hunter College, 695 Park Avenue, NY 10065, United States of America
| | - Steven Ramsey
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
- Department of Chemistry, Lehman College, 250 Bedford Park Blvd. West, Bronx, NY 10468, United States of America
| | - Pierpaolo Cordone
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
- Department of Chemistry, Hunter College, 695 Park Avenue, NY 10065, United States of America
| | - Lauren Wickstrom
- Department of Science, Borough of Manhattan Community College, 199 Chambers Street, New York, NY 10007, United States of America
| | - Wayne W. Harding
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
- PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
- Department of Chemistry, Hunter College, 695 Park Avenue, NY 10065, United States of America
| | - Tom Kurtzman
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
- PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
- Department of Chemistry, Lehman College, 250 Bedford Park Blvd. West, Bronx, NY 10468, United States of America
| | - Emilio Gallicchio
- Department of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, NY 11210, United States of America
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
- PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America
- * E-mail:
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55
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Escalante DE, Aksan A. Role of Water Hydrogen Bonding on Transport of Small Molecules inside Hydrophobic Channels. J Phys Chem B 2019; 123:6673-6685. [PMID: 31310534 DOI: 10.1021/acs.jpcb.9b03060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We conducted a systematic analysis of water networking inside smooth hyperboloid hydrophobic structures (cylindrical, barrel, and hourglass shapes) to elucidate the role of water hydrogen bonding on the transport of small hydrophobic molecules (ligands). Through a series of molecular dynamics simulations, we established that a hydrogen-bonded network forming along the centerline resulted in a water exclusion zone adjacent to the walls. The size of the exclusion zone is a function of the geometry and the nonbonded interaction strength, defining the effective hydrophobicity of the structure. Exclusion of water molecules from this zone results in lower apparent viscosity, leading to acceleration of ligand transport up to 7 times faster than that measured in the bulk. Transport of ligands into and out of the hydrophobic structures was shown to be controlled by a single water molecule that capped the narrow regions in the structure. This mechanism provides physical insights into the behavior and role of water in the bottleneck regions of hydrophobic enzyme channels. These findings were then used in a sister publication [ Escalante , D. E. , Comput. Struct. Biotechnol. J. 2019 17 757 760 ] to develop a model that can accurately predict the transport of ligands along nanochannels of broad-substrate specificity enzymes.
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Affiliation(s)
- Diego E Escalante
- Department of Mechanical Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Alptekin Aksan
- Department of Mechanical Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States.,BioTechnology Institute , University of Minnesota , St. Paul , Minnesota 55108 , United States
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56
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Shao Q. A computational avenue towards understanding and design of zwitterionic anti-biofouling materials. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1599118] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Qing Shao
- Chemical and Materials Engineering, University of Kentucky, Lexington KY, USA
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57
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Wall ME, Calabró G, Bayly CI, Mobley DL, Warren GL. Biomolecular Solvation Structure Revealed by Molecular Dynamics Simulations. J Am Chem Soc 2019; 141:4711-4720. [PMID: 30834751 DOI: 10.1021/jacs.8b13613] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
To compare ordered water positions from experiment with those from molecular dynamics (MD) simulations, a number of MD models of water structure in crystalline endoglucanase were calculated. The starting MD model was derived from a joint X-ray and neutron diffraction crystal structure, enabling the use of experimentally assigned protonation states. Simulations were performed in the crystalline state, using a periodic 2 × 2 × 2 supercell with explicit solvent. Water X-ray and neutron scattering density maps were computed from MD trajectories using standard macromolecular crystallography methods. In one set of simulations, harmonic restraints were applied to bias the protein structure toward the crystal structure. For these simulations, the recall of crystallographic waters using strong peaks in the MD water electron density was very good, and there also was substantial visual agreement between the boomerang-like wings of the neutron scattering density and the crystalline water hydrogen positions. An unrestrained simulation also was performed. For this simulation, the recall of crystallographic waters was much lower. For both restrained and unrestrained simulations, the strongest water density peaks were associated with crystallographic waters. The results demonstrate that it is now possible to recover crystallographic water structure using restrained MD simulations but that it is not yet reasonable to expect unrestrained MD simulations to do the same. Further development and generalization of MD water models for force-field development, macromolecular crystallography, and medicinal chemistry applications is now warranted. In particular, the combination of room-temperature crystallography, neutron diffraction, and crystalline MD simulations promises to substantially advance modeling of biomolecular solvation.
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Affiliation(s)
- Michael E Wall
- Computer, Computational, and Statistical Sciences Division , Los Alamos National Laboratory , Mail Stop B256 , Los Alamos , New Mexico 87545 , United States
| | - Gaetano Calabró
- OpenEye Scientific Software , 9 Bisbee Court, Unit D , Santa Fe , New Mexico 87507 , United States.,Department of Pharmaceutical Sciences , University of California, Irvine , 3134B Natural Sciences 1 , Irvine , California 92697 , United States
| | - Christopher I Bayly
- OpenEye Scientific Software , 9 Bisbee Court, Unit D , Santa Fe , New Mexico 87507 , United States
| | - David L Mobley
- Department of Pharmaceutical Sciences , University of California, Irvine , 3134B Natural Sciences 1 , Irvine , California 92697 , United States.,Department of Chemistry , University of California, Irvine , 3134B Natural Sciences 1 , Irvine , California 92697 , United States
| | - Gregory L Warren
- OpenEye Scientific Software , 9 Bisbee Court, Unit D , Santa Fe , New Mexico 87507 , United States
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58
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Lee H, Dehez F, Chipot C, Lim HK, Kim H. Enthalpy-Entropy Interplay in π-Stacking Interaction of Benzene Dimer in Water. J Chem Theory Comput 2019; 15:1538-1545. [PMID: 30721623 DOI: 10.1021/acs.jctc.8b00880] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aromatic groups can engage in an interesting class of noncovalent interactions termed π-π interactions, which play a pivotal role in stabilizing a variety of molecular architectures, including nucleic acids, proteins, and supramolecular assemblies. When the aromatic compounds interact with each other in an aqueous environment, their association is facilitated by the hydrophobic effect-the trend of nonpolar solutes to aggregate in a polar solution. To develop an in-depth understanding of hydrophobic association, we investigate in the present work π-π interactions in water, employing as a paradigm the benzene dimer. Using DFT-CES, a mean-field QM/MM method recently developed by our group, we describe the benzene solute at a quantum-mechanical level. Full consideration of detailed solute-electron density enables an optimal description of the solute-solvent interactions, leading to an accurate prediction of hydration free energies. In π-stacking of benzene, we find an entropic stabilization associated with the shrinkage of the solvent-excluded volume, which agrees with the theory of hydrophobic effect at subnanoscales. However, at the equilibrium binding distance of the benzene dimer, we find that the entropic stabilization nearly cancels out due to the enthalpic cost required for dewetting the internal space. Such an enthalpy-entropy compensation leads the association free energy to be predominantly dictated by the solute-solute interaction enthalpy. The present work offers new insight into the mechanistic role of water and the primary thermodynamic driving force of hydrophobic association.
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Affiliation(s)
- Hankyul Lee
- Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , Yuseong-gu, Daejeon 34141 , Korea
| | - François Dehez
- LPCT , UMR 7019 Université de Lorraine CNRS , Vandœuvre-lès-Nancy F-54500 , France.,Laboratoire International Associé CNRS and University of Illinois at Urbana-Champaign, Vandœuvre-lès-Nancy F-54506 , France
| | - Christophe Chipot
- LPCT , UMR 7019 Université de Lorraine CNRS , Vandœuvre-lès-Nancy F-54500 , France.,Laboratoire International Associé CNRS and University of Illinois at Urbana-Champaign, Vandœuvre-lès-Nancy F-54506 , France.,Department of Physics , University of Illinois at Urbana-Champaign , 1110 West Green Street , Urbana , Illinois 61801 , United States
| | - Hyung-Kyu Lim
- Division of Chemical Engineering and Bioengineering , Kangwon National University , Chuncheon , Gangwon-do 24341 , Korea
| | - Hyungjun Kim
- Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , Yuseong-gu, Daejeon 34141 , Korea
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59
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Kanduč M, Kim WK, Roa R, Dzubiella J. Transfer Free Energies and Partitioning of Small Molecules in Collapsed PNIPAM Polymers. J Phys Chem B 2019; 123:720-728. [PMID: 30576139 DOI: 10.1021/acs.jpcb.8b10134] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A central quantity in the design of functional hydrogels used as nanocarrier systems, for instance, for drug delivery or adaptive nanocatalysis, is the partition ratio, which quantifies the uptake of a molecular substance by the polymer matrix. By employing all-atom molecular dynamics simulations, we study the solvation and partitioning (with respect to bulk water) of small subnanometer-sized solutes in a dense matrix of collapsed poly( N-isopropylacrylamide) (PNIPAM) polymers above the lower critical solution temperature in aqueous solution. We examine the roles of the solute's polarity and its size on the solubility properties in the thermoresponsive polymer. We show that the transfer free energies of nonpolar solutes from bulk water into the polymer are favorable and scale in a good approximation with the solute's surface area. Even for small solute size variation, partitioning can vary over orders of magnitude. A polar nature of the solute, on the other hand, generally opposes the transfer, at least for alkyl solutes. Finally, we find a strong correlation between the transfer free energies in the gel and the adsorption free energies on a single extended polymer chain, which enables us to relate the partition ratios in the swollen and collapsed state of a PNIPAM gel.
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Affiliation(s)
- Matej Kanduč
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany.,Jožef Stefan Institute , Jamova 39 , SI-1001 Ljubljana , Slovenia
| | - Won Kyu Kim
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany
| | - Rafael Roa
- Departamento de Física Aplicada I, Facultad de Ciencias , Universidad de Málaga , Campus de Teatinos s/n , E-29071 Málaga , Spain
| | - Joachim Dzubiella
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany.,Applied Theoretical Physics-Computational Physics, Physikalisches Institut , Albert-Ludwigs-Universität Freiburg , Hermann-Herder Strasse 3 , D-79104 Freiburg , Germany
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60
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Gade HM, Wanjari PP. Molecular Dynamics Simulations of Water-Mediated Cholesterol Capture within an Open-Ended Single-Walled Carbon Nanotube. Chemphyschem 2019; 20:142-147. [PMID: 30444311 DOI: 10.1002/cphc.201800880] [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: 09/18/2018] [Revised: 11/16/2018] [Indexed: 11/11/2022]
Abstract
The excess concentration of cholesterol in the bloodstream can be brought down to a safer level by utilizing a potential cholesterol-binding agent such as a carbon nanotube (CNT). Here, we have probed solvent-mediated interactions between cholesterol and CNT by performing molecular dynamics simulations and potential-of-mean force (PMF) calculations. Simulations predict favorable interactions between water-mediated cholesterol and CNT owing to strong mutual interactions between them, whereas water plays an opposing role in the association. The breakdown of PMF into its enthalpic and entropic contributions indicates that contrary to traditional entropy-driven hydrophobic association, the cholesterol encapsulation within a CNT is primarily driven by enthalpy.
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Affiliation(s)
- Hrushikesh M Gade
- Department of Chemical Engineering, Visvesvaraya National Institute of Technology (VNIT), Nagpur, Maharashtra, India
| | - Piyush P Wanjari
- Department of Chemical Engineering, Visvesvaraya National Institute of Technology (VNIT), Nagpur, Maharashtra, India
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61
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Yonetani Y. Water access and ligand dissociation at the binding site of proteins. J Chem Phys 2018; 149:175102. [PMID: 30408972 DOI: 10.1063/1.5042491] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Although water is undoubtedly an essential mediator of protein-ligand interactions, whether or not such water molecules are critical for the progress of ligand dissociation remains unclear. To gain a more complete understanding, molecular dynamics simulations are performed with two molecular systems, rigid model binding sites and trypsin-benzamidine. Free-energy landscapes are calculated with a suitably chosen solvent coordinate, which well describes water access to the ligand binding site. The results of free energy provided clear description of water-ligand exchange process, where two different mechanisms appear depending on whether the binding site is buried or not. As the site is more buried, water access is more difficult. When water does not access the site, ligand dissociation produces a large energy barrier, i.e., slow dissociation kinetics. This indicates that control of ligand dissociation kinetics becomes possible with burying the binding site. However, the results also showed that appropriate burying is important because burying reduces not only water access but also ligand binding. The role of the protein structural change is also discussed; it likely plays a similar role to water access because during ligand dissociation, it can make new coordination with the ligand binding site like water. These results contribute to the future pharmaceutical drug design and will be useful for fundamental exploration of various molecular events.
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Affiliation(s)
- Yoshiteru Yonetani
- Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology (QST), Tokai-mura, Ibaraki 319-1195, Japan
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62
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Ricci CG, McCammon JA. Heterogeneous Solvation in Distinctive Protein-Protein Interfaces Revealed by Molecular Dynamics Simulations. J Phys Chem B 2018; 122:11695-11701. [PMID: 30252476 DOI: 10.1021/acs.jpcb.8b07773] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Water, despite being a driving force in biochemical processes, has an elusively complex microscopic behavior. While water can increase its local density near amphiphilic protein surfaces, water is also thought to evaporate from hydrophobic surfaces and cavities, an effect known as "dewetting". The existence and extent of dewetting effects remains elusive due to the difficulty in observing clear "drying" transitions in experiments or simulations. Here, we use explicit solvent molecular dynamics (MD) simulations to study the molecular solvation at the binding interfaces of two distinctive molecular complexes: the highly hydrophilic barnase-barstar and the highly hydrophobic MDM2-p53. Our simulations, in conjunction with simple volumetric analyses, reveal a strikingly different water behavior at the binding interfaces of these two molecular complexes. In both complexes, we observe significant changes in the water local density as the two proteins approach, supporting the existence of a clear dewetting transition in the case of MDM2-p53, with an onset distance of 5.6-7.6 Å. Furthermore, the solvation analysis reported herein is a valuable tool to capture and quantify persistent or transient dewetting events in future explicit solvent MD simulations.
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63
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Henderson JA, Harris RC, Tsai CC, Shen J. How Ligand Protonation State Controls Water in Protein-Ligand Binding. J Phys Chem Lett 2018; 9:5440-5444. [PMID: 30188715 PMCID: PMC6467052 DOI: 10.1021/acs.jpclett.8b02440] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The role of water in protein-ligand binding has been an intensely studied topic in recent years; however, how ligand protonation state change perturbs water has not been considered. Here we show that water dynamics and interactions can be controlled by the protonation state of ligand using continuous constant pH molecular dynamics simulations of two closely related model systems, β-secretase 1 and 2 (BACE1 and BACE2), in complex with a small-molecule inhibitor. Simulations revealed that, upon binding, the inhibitor pyrimidine ring remains deprotonated in BACE1 but becomes protonated in BACE2. Pyrimidine protonation results in water displacement, rigidification of the binding pocket, and shift in the ligand binding mode from water-mediated to direct hydrogen bonding. These findings not only support but also rationalize the most recent structure-selectivity data in BACE1 drug design. Binding-induced protonation state changes are likely common; our work offers a glimpse at how modeling protein-ligand binding while allowing ligand titration can further advance the understanding of water and structure-based drug design.
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Affiliation(s)
- Jack A Henderson
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Robert C Harris
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Cheng-Chieh Tsai
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Jana Shen
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
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64
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Weiß RG, Chudoba R, Setny P, Dzubiella J. Affinity, kinetics, and pathways of anisotropic ligands binding to hydrophobic model pockets. J Chem Phys 2018; 149:094902. [DOI: 10.1063/1.5025118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- R. Gregor Weiß
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, D-12489 Berlin, Germany
- Laboratory of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Richard Chudoba
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, D-12489 Berlin, Germany
- Research Group Simulations of Energy Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Straße 3, D-79104 Freiburg, Germany
| | - Piotr Setny
- Centre of New Technologies, University of Warsaw, Stefana Banacha 2c, 00-927 Warsaw, Poland
| | - Joachim Dzubiella
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, D-12489 Berlin, Germany
- Research Group Simulations of Energy Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Straße 3, D-79104 Freiburg, Germany
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65
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Guo J, Collins S, Miller WT, Rizzo RC. Identification of a Water-Coordinating HER2 Inhibitor by Virtual Screening Using Similarity-Based Scoring. Biochemistry 2018; 57:4934-4951. [PMID: 29975516 PMCID: PMC6110523 DOI: 10.1021/acs.biochem.8b00524] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Human
epidermal growth factor receptor 2 (HER2) is a validated
breast cancer drug target for small molecule inhibitors that target
the ATP-binding pocket of the kinase domain. In this work, a large-scale
virtual screen was performed to a novel homology model of HER2, in
a hypothesized “fully active” state, that considered
water-mediated interactions during the prioritization of compounds
for experimental testing. This screen led to the identification of
a new inhibitor with micro molar affinity and potency (Kd = 7.0 μM, IC50 = 4.6 μM). Accompanying
molecular dynamics simulations showed that inhibitor binding likely
involves water coordination through an important water-mediated network
previously identified in our laboratory. The predicted binding geometry
also showed a remarkable overlap with the crystallographic poses for
two previously reported inhibitors of the related Chk1 kinase. Concurrent
with the HER2 studies, we developed formalized computational protocols
that leverage solvated footprints (per-residue interaction maps that
include bridging waters) to identify ligands that can “coordinate”
or “displace” key binding site waters. Proof-of-concept
screens targeting HIVPR and PARP1 demonstrate that molecules with
high footprint overlap can be effectively identified in terms of their
coordination or displacement patterns relative to a known reference.
Overall, the procedures developed as a result of this study should
be useful for researchers targeting HER2 and, more generally, for
any protein in which the identification of compounds that exploit
binding site waters is desirable.
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66
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Galamba N, Pipolo S. On the Binding Free Energy and Molecular Origin of Sickle Cell Hemoglobin Aggregation. J Phys Chem B 2018; 122:7475-7483. [DOI: 10.1021/acs.jpcb.8b03708] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- N. Galamba
- Centro de Química e Bioquímica and Biosystems and Integrative Sciences Institute, Faculdade de Ciências da Universidade de Lisboa, Edifício C8, Campo Grande, 1749-016 Lisboa, Portugal
| | - Silvio Pipolo
- Université
de Lille, CNRS, Centrale Lille, ENSCL, Université d’
Artois UMR 8181 − UCCS Unité de Catalyse et Chimie du
Solide, F-59000, Lille, France
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67
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Nikam R, Xu X, Ballauff M, Kanduč M, Dzubiella J. Charge and hydration structure of dendritic polyelectrolytes: molecular simulations of polyglycerol sulphate. SOFT MATTER 2018; 14:4300-4310. [PMID: 29780980 PMCID: PMC5977385 DOI: 10.1039/c8sm00714d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 05/09/2018] [Indexed: 06/08/2023]
Abstract
Macromolecules based on dendritic or hyperbranched polyelectrolytes have been emerging as high potential candidates for biomedical applications. Here we study the charge and solvation structure of dendritic polyglycerol sulphate (dPGS) of generations 0 to 3 in aqueous sodium chloride solution by explicit-solvent molecular dynamics computer simulations. We characterize dPGS by calculating several important properties such as relevant dPGS radii, molecular distributions, the solvent accessible surface area, and the partial molecular volume. In particular, as the dPGS exhibits high charge renormalization effects, we address the challenges of how to obtain a well-defined effective charge and surface potential of dPGS for practical applications. We compare implicit- and explicit-solvent approaches in our all-atom simulations with the coarse-grained simulations from our previous work. We find consistent values for the effective electrostatic size (i.e., the location of the effective charge of a Debye-Hückel sphere) within all the approaches, deviating at most by the size of a water molecule. Finally, the excess chemical potential of water insertion into dPGS and its thermodynamic signature are presented and rationalized.
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Affiliation(s)
- Rohit Nikam
- Research Group Simulations of Energy Materials
, Helmholtz-Zentrum Berlin für Materialien und Energie
,
Hahn-Meitner-Platz 1
, D-14109 Berlin
, Germany
.
;
- Institut für Physik
, Humboldt-Universität zu Berlin
,
Newtonstr. 15
, D-12489 Berlin
, Germany
| | - Xiao Xu
- School of Chemical Engineering
, Nanjing University of Science and Technology
,
200 Xiao Ling Wei
, Nanjing 210094
, P. R. China
| | - Matthias Ballauff
- Institut für Physik
, Humboldt-Universität zu Berlin
,
Newtonstr. 15
, D-12489 Berlin
, Germany
- Soft Matter and Functional Materials
, Helmholtz-Zentrum Berlin für Materialien und Energie
,
Hahn-Meitner-Platz 1
, D-14109 Berlin
, Germany
- Multifunctional Biomaterials for Medicine
, Helmholtz Virtual Institute
,
Kantstr. 55
, D-14513 Teltow-Seehof
, Germany
| | - Matej Kanduč
- Research Group Simulations of Energy Materials
, Helmholtz-Zentrum Berlin für Materialien und Energie
,
Hahn-Meitner-Platz 1
, D-14109 Berlin
, Germany
.
;
| | - Joachim Dzubiella
- Research Group Simulations of Energy Materials
, Helmholtz-Zentrum Berlin für Materialien und Energie
,
Hahn-Meitner-Platz 1
, D-14109 Berlin
, Germany
.
;
- Physikalisches Institut
, Albert-Ludwigs-Universität Freiburg
,
Hermann-Herder Str. 3
, D-79104 Freiburg
, Germany
.
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68
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Sato SB, Sugiura M, Kurihara T. Dimer-monomer equilibrium of human HSP27 is influenced by the in-cell macromolecular crowding environment and is controlled by fatty acids and heat. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:692-701. [PMID: 29635040 DOI: 10.1016/j.bbapap.2018.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/23/2022]
Abstract
Small heat shock protein 27 (HSP27) is an essential element of the proteostasis network in human cells. The HSP27 monomer coexists with the dimer, which can bind unfolded client proteins. Here, we evaluated the in-cell dimer-monomer equilibrium and its relevance to the binding of client proteins in a normal human vascular endothelial cell line. When cells were treated with a membrane-permeable crosslinker, the protein existed primarily as a free monomer (27 kDa) with a markedly smaller percentage of dimer (54 kDa), hetero-conjugates, and minor smear-like bands. When the protein was crosslinked in a cell-free lysate, two of the hetero-conjugates that were crosslinked in live cells were also detected, but the dimer and other complexes were absent. However, when cells were pretreated with fatty acid (FA) and/or heat (42.5 °C), dissociation of the dimer was selectively prevented and two types of covalently linked dimers were increased. These changes occurred most prominently in cells treated with docosahexaenoic acid (DHA) and heat, which appeared to intensify the heat resistance of the cell. Both the formation of covalently linked dimers and heat resistance were prevented by N-acetylcysteine. By contrast, nearly all of the free monomers in the lysate converted to disulfide bond-linked dimers by a simple, long incubation at 4 °C. These results strongly suggest that the monomer-dimer equilibrium of HSP27 was inversed between the in-cell and cell-free systems. Temperature- and amphiphile-regulated dimerization was restricted probably due to the low hydration of the in-cell crowding environment.
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Affiliation(s)
- Satoshi B Sato
- Department of Biophysics, Division of Biological Science, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| | - Miwa Sugiura
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Tatsuo Kurihara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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69
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Microcystins: Synthesis and structure–activity relationship studies toward PP1 and PP2A. Bioorg Med Chem 2018; 26:1118-1126. [DOI: 10.1016/j.bmc.2017.08.040] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/19/2017] [Accepted: 08/23/2017] [Indexed: 11/19/2022]
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70
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Bucher D, Stouten P, Triballeau N. Shedding Light on Important Waters for Drug Design: Simulations versus Grid-Based Methods. J Chem Inf Model 2018; 58:692-699. [DOI: 10.1021/acs.jcim.7b00642] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Denis Bucher
- Galapagos SASU, 102 Avenue Gaston Roussel, 93230 Romainville, France
| | - Pieter Stouten
- Galapagos NV, Generaal De Wittelaan L11 A3, 2800 Mechelen, Belgium
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71
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Graham SE, Smith RD, Carlson HA. Predicting Displaceable Water Sites Using Mixed-Solvent Molecular Dynamics. J Chem Inf Model 2018; 58:305-314. [PMID: 29286658 PMCID: PMC6190669 DOI: 10.1021/acs.jcim.7b00268] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Water molecules are an important factor in protein-ligand binding. Upon binding of a ligand with a protein's surface, waters can either be displaced by the ligand or may be conserved and possibly bridge interactions between the protein and ligand. Depending on the specific interactions made by the ligand, displacing waters can yield a gain in binding affinity. The extent to which binding affinity may increase is difficult to predict, as the favorable displacement of a water molecule is dependent on the site-specific interactions made by the water and the potential ligand. Several methods have been developed to predict the location of water sites on a protein's surface, but the majority of methods are not able to take into account both protein dynamics and the interactions made by specific functional groups. Mixed-solvent molecular dynamics (MixMD) is a cosolvent simulation technique that explicitly accounts for the interaction of both water and small molecule probes with a protein's surface, allowing for their direct competition. This method has previously been shown to identify both active and allosteric sites on a protein's surface. Using a test set of eight systems, we have developed a method using MixMD to identify conserved and displaceable water sites. Conserved sites can be determined by an occupancy-based metric to identify sites which are consistently occupied by water even in the presence of probe molecules. Conversely, displaceable water sites can be found by considering the sites which preferentially bind probe molecules. Furthermore, the inclusion of six probe types allows the MixMD method to predict which functional groups are capable of displacing which water sites. The MixMD method consistently identifies sites which are likely to be nondisplaceable and predicts the favorable displacement of water sites that are known to be displaced upon ligand binding.
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Affiliation(s)
- Sarah E. Graham
- Department of Biophysics, College of Pharmacy, University of Michigan, 428 Church St., Ann Arbor, Michigan, 48109-1065
| | - Richard D. Smith
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church St., Ann Arbor, Michigan, 48109-1065
| | - Heather A. Carlson
- Department of Biophysics, College of Pharmacy, University of Michigan, 428 Church St., Ann Arbor, Michigan, 48109-1065
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church St., Ann Arbor, Michigan, 48109-1065
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72
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Ricci CG, Li B, Cheng LT, Dzubiella J, McCammon JA. Tailoring the Variational Implicit Solvent Method for New Challenges: Biomolecular Recognition and Assembly. Front Mol Biosci 2018; 5:13. [PMID: 29484300 PMCID: PMC5816062 DOI: 10.3389/fmolb.2018.00013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/26/2018] [Indexed: 01/12/2023] Open
Abstract
Predicting solvation free energies and describing the complex water behavior that plays an important role in essentially all biological processes is a major challenge from the computational standpoint. While an atomistic, explicit description of the solvent can turn out to be too expensive in large biomolecular systems, most implicit solvent methods fail to capture “dewetting” effects and heterogeneous hydration by relying on a pre-established (i.e., guessed) solvation interface. Here we focus on the Variational Implicit Solvent Method, an implicit solvent method that adds water “plasticity” back to the picture by formulating the solvation free energy as a functional of all possible solvation interfaces. We survey VISM's applications to the problem of molecular recognition and report some of the most recent efforts to tailor VISM for more challenging scenarios, with the ultimate goal of including thermal fluctuations into the framework. The advances reported herein pave the way to make VISM a uniquely successful approach to characterize complex solvation properties in the recognition and binding of large-scale biomolecular complexes.
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Affiliation(s)
- Clarisse Gravina Ricci
- Department of Pharmacology and Department of Chemistry and Biochemistry, National Biomedical Computation Resource, University of California, San Diego, La Jolla, CA, United States
| | - Bo Li
- Department of Mathematics, University of California, San Diego, La Jolla, CA, United States.,Quantitative Biology Graduate Program, University of California, San Diego, La Jolla, CA, United States
| | - Li-Tien Cheng
- Department of Mathematics, University of California, San Diego, La Jolla, CA, United States
| | - Joachim Dzubiella
- Institut für Physik, Humboldt-Universität zu Berlin, Berlin, Germany.,Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Berlin, Germany
| | - J Andrew McCammon
- Department of Pharmacology and Department of Chemistry and Biochemistry, National Biomedical Computation Resource, University of California, San Diego, La Jolla, CA, United States
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73
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Zheng M, Zhao J, Cui C, Fu Z, Li X, Liu X, Ding X, Tan X, Li F, Luo X, Chen K, Jiang H. Computational chemical biology and drug design: Facilitating protein structure, function, and modulation studies. Med Res Rev 2018; 38:914-950. [DOI: 10.1002/med.21483] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/13/2017] [Accepted: 12/15/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Mingyue Zheng
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
| | - Jihui Zhao
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
| | - Chen Cui
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
| | - Zunyun Fu
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
| | - Xutong Li
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
| | - Xiaohong Liu
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
- School of Life Science and Technology; ShanghaiTech University; Shanghai China
| | - Xiaoyu Ding
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
| | - Xiaoqin Tan
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
| | - Fei Li
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
- Department of Chemistry, College of Sciences; Shanghai University; Shanghai China
| | - Xiaomin Luo
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
| | - Kaixian Chen
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
- School of Life Science and Technology; ShanghaiTech University; Shanghai China
| | - Hualiang Jiang
- State Key Laboratory of Drug Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica; Chinese Academy of Sciences; Shanghai China
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74
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Tang Z, Chang CEA. Binding Thermodynamics and Kinetics Calculations Using Chemical Host and Guest: A Comprehensive Picture of Molecular Recognition. J Chem Theory Comput 2018; 14:303-318. [PMID: 29149564 PMCID: PMC5920803 DOI: 10.1021/acs.jctc.7b00899] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding the fine balance between changes of entropy and enthalpy and the competition between a guest and water molecules in molecular binding is crucial in fundamental studies and practical applications. Experiments provide measurements. However, illustrating the binding/unbinding processes gives a complete picture of molecular recognition not directly available from experiments, and computational methods bridge the gaps. Here, we investigated guest association/dissociation with β-cyclodextrin (β-CD) by using microsecond-time-scale molecular dynamics (MD) simulations, postanalysis and numerical calculations. We computed association and dissociation rate constants, enthalpy, and solvent and solute entropy of binding. All the computed values of kon, koff, ΔH, ΔS, and ΔG using GAFF-CD and q4MD-CD force fields for β-CD could be compared with experimental data directly and agreed reasonably with experiment findings. In addition, our study further interprets experiments. Both force fields resulted in similar computed ΔG from independently computed kinetics rates, ΔG = -RT ln(kon·C0/koff), and thermodynamics properties, ΔG = ΔH - TΔS. The water entropy calculations show that the entropy gain of desolvating water molecules are a major driving force, and both force fields have the same strength of nonpolar attractions between solutes and β-CD as well. Water molecules play a crucial role in guest binding to β-CD. However, collective water/β-CD motions could contribute to different computed kon and ΔH values by different force fields, mainly because the parameters of β-CD provide different motions of β-CD, hydrogen-bond networks of water molecules in the cavity of free β-CD, and strength of desolvation penalty. As a result, q4MD-CD suggests that guest binding is mostly driven by enthalpy, while GAFF-CD shows that gaining entropy is the major driving force of binding. The study deepens our understanding of ligand-receptor recognition and suggests strategies for force field parametrization for accurately modeling molecular systems.
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Affiliation(s)
- Zhiye Tang
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Chia-en A. Chang
- Department of Chemistry, University of California, Riverside, California 92521, United States
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75
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Wei G, Venkataraman S, Yang YY, Hedrick JL, Prabhu VM. Enthalpy-driven micellization of oligocarbonate-fluorene end-functionalized Poly(ethylene glycol). POLYMER 2018. [DOI: 10.1016/j.polymer.2017.11.057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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76
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Wei G, Venkataraman S, Yang YY, Hedrick JL, Prabhu VM. Enthalpy-driven micellization of oligocarbonate-fluorene end-functionalized Poly(ethylene glycol) ☆. Macromolecules 2018; 134:https://doi.org/10.1016/j.polymer.2017.11.057. [PMID: 33208982 PMCID: PMC7670547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A fluorescent pyrene probe method was applied to measure the critical micelle concentration (CMC) of oligocarbonate-fluorene end-functionalized poly(ethylene glycol) (FmE445Fm) triblock copolymers in water. The CMC decreases with lower temperature and higher values of the hydrophobic block length, m. When analyzed by a closed-assembly micelle model, the estimated energetic parameters find a negative ΔH°mic and small positive ΔS°mic suggestive of enthalpy-driven micellization, which differs from entropy-driven oxyethylene/oxybutylene triblock copolymers and octaethylene glycol-n-alkyl ethers. The enthalpy-driven micellization of FmE445Fm may result from the limited hydration of individual hydrophobic F blocks that leads to few hydrogen-bonded waters released during F block association. The π-π stacking oligocarbonate-fluorene system also observed enthalpy-entropy compensation when compared to a series of published data on diblock and triblock copolymer systems. An anomalously low partition equilibrium constant for m = 15.3 implies a tightly-packed core that excludes pyrene intercalation into the fluorene core. This is discussed along with the possible limited applicability to estimate the CMC and potential model drug molecule insertions into the intercalated micelle core.
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Affiliation(s)
- Guangmin Wei
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, United States
| | - Shrinivas Venkataraman
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore
| | - Yi Yan Yang
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore
| | - James L. Hedrick
- IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, United States
| | - Vivek M. Prabhu
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, United States
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77
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Abstract
This review focuses on papers published since 2000 on the topic of the properties of solutes in water. More specifically, it evaluates the state of the art of our understanding of the complex relationship between the shape of a hydrophobe and the hydrophobic effect. To highlight this, we present a selection of references covering both empirical and molecular dynamics studies of small (molecular-scale) solutes. These include empirical studies of small molecules, synthetic hosts, crystalline monolayers, and proteins, as well as in silico investigations of entities such as idealized hard and soft spheres, small solutes, hydrophobic plates, artificial concavity, molecular hosts, carbon nanotubes and spheres, and proteins.
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Affiliation(s)
- Matthew B Hillyer
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118;
| | - Bruce C Gibb
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118;
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78
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Kang SM, Kim DH, Lee KY, Park SJ, Yoon HJ, Lee SJ, Im H, Lee BJ. Functional details of the Mycobacterium tuberculosis VapBC26 toxin-antitoxin system based on a structural study: insights into unique binding and antibiotic peptides. Nucleic Acids Res 2017; 45:8564-8580. [PMID: 28575388 PMCID: PMC5737657 DOI: 10.1093/nar/gkx489] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/25/2017] [Indexed: 11/16/2022] Open
Abstract
Toxin-antitoxin (TA) systems are essential for bacterial persistence under stressful conditions. In particular, Mycobacterium tuberculosis express VapBC TA genes that encode the stable VapC toxin and the labile VapB antitoxin. Under normal conditions, these proteins interact to form a non-toxic TA complex, but the toxin is activated by release from the antitoxin in response to unfavorable conditions. Here, we present the crystal structure of the M. tuberculosis VapBC26 complex and show that the VapC26 toxin contains a pilus retraction protein (PilT) N-terminal (PIN) domain that is essential for ribonuclease activity and that, the VapB26 antitoxin folds into a ribbon-helix-helix DNA-binding motif at the N-terminus. The active site of VapC26 is sterically blocked by the flexible C-terminal region of VapB26. The C-terminal region of free VapB26 adopts an unfolded conformation but forms a helix upon binding to VapC26. The results of RNase activity assays show that Mg2+ and Mn2+ are essential for the ribonuclease activity of VapC26. As shown in the nuclear magnetic resonance spectra, several residues of VapB26 participate in the specific binding to the promoter region of the VapBC26 operon. In addition, toxin-mimicking peptides were designed that inhibit TA complex formation and thereby increase toxin activity, providing a novel approach to the development of new antibiotics.
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Affiliation(s)
- Sung-Min Kang
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Do-Hee Kim
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Ki-Young Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Sung Jean Park
- College of Pharmacy, Gachon University, 534-2 Yeonsu-dong, Yeonsu-gu, Incheon 406-799, Republic of Korea
| | - Hye-Jin Yoon
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea
| | - Sang Jae Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Hookang Im
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Bong-Jin Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
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79
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Dharra R, Talwar S, Singh Y, Gupta R, Cirillo JD, Pandey AK, Kulharia M, Mehta PK. Rational design of drug-like compounds targeting Mycobacterium marinum MelF protein. PLoS One 2017; 12:e0183060. [PMID: 28873466 PMCID: PMC5584760 DOI: 10.1371/journal.pone.0183060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 07/28/2017] [Indexed: 11/19/2022] Open
Abstract
The mycobacterial mel2 locus (mycobacterial enhanced infection locus, Rv1936-1941) is Mycobacterium marinum and M. tuberculosis specific, which can withstand reactive oxygen species (ROS) and reactive nitrogen species (RNS) induced stress. A library of over a million compounds was screened using in silico virtual ligand screening (VLS) to identify inhibitors against the modeled structure of MelF protein expressed by melF of mel2 locus so that M. marinum’s ability to withstand ROS/RNS stress could be reduced. The top ranked 1000 compounds were further screened to identify 178 compounds to maximize the scaffold diversity by manually evaluating the interaction of each compound with the target site. M. marinum melF was cloned, expressed and purified as maltose binding protein (MBP)-tagged recombinant protein in Escherichia coli. After establishing the flavin dependent oxidoreductase activity of MelF (~ 84 kDa), the inhibitors were screened for the inhibition of enzyme activity of whole cell lysate (WCL) and the purified MelF. Amongst these, 16 compounds could significantly inhibit the enzyme activity of purified MelF. For the six best inhibitory compounds, the minimal inhibitory concentration (MIC) was determined to be 3.4–19.4 μM and 13.5–38.8 μM for M. marinum and M. tuberculosis, respectively. Similarly, the minimal bactericidal concentration (MBC) was determined to be 6.8–38.8 μM and 27–38.8 μM against M. marinum and M. tuberculosis, respectively. One compound each in combination with isoniazid (INH) also showed synergistic inhibitory effect against M. marinum and M. tuberculosis with no cytotoxicity in HeLa cells. Interestingly, these inhibitors did not display any non-specific protein-structure destabilizing effect. Such inhibitors targeting the anti-ROS/RNS machinery may facilitate the efficient killing of replicating and nonreplicating mycobacteria inside the host cells.
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Affiliation(s)
- Renu Dharra
- Centre for Biotechnology, Maharshi Dayanand University (MDU), Rohtak, India
| | - Sakshi Talwar
- Translational Health Science and Technology Institute (THSTI), Faridabad, India
| | - Yogesh Singh
- Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Rani Gupta
- Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Jeffrey D. Cirillo
- Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College Station, Texas, United States of America
| | - Amit K. Pandey
- Translational Health Science and Technology Institute (THSTI), Faridabad, India
| | - Mahesh Kulharia
- School of Basic and Applied Science, Central University of Punjab, Bathinda, India
- * E-mail: (MK); (PKM)
| | - Promod K. Mehta
- Centre for Biotechnology, Maharshi Dayanand University (MDU), Rohtak, India
- * E-mail: (MK); (PKM)
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80
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Bodnarchuk MS, Dini D, Heyes DM, Breakspear A, Chahine S. Molecular Dynamics Studies of Overbased Detergents on a Water Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:7263-7270. [PMID: 28665133 DOI: 10.1021/acs.langmuir.7b00827] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Molecular dynamics (MD) simulations are reported of model overbased detergent nanoparticles on a model water surface which mimic their behavior on a Langmuir trough or large water droplet in engine oil. The simulations predict that the structure of the nanoparticle on a water surface is different to when it is immersed in a bulk hydrophobic solvent. The surfactant tails are partly directed out of the water, while the carbonate core maximizes its extent of contact with the water. Umbrella sampling calculations of the potential of mean force between two particles showed that they are associated with varying degrees with a maximum binding free energy of ca. 10 kBT for the salicylate stabilized particle, ca. 8 kBT for a sulfurized alkyl phenate stabilized particle, and ca. 5 kBT for a sulfonate stabilized particle. The differences in the strength of attraction depend on the proximity of nearest approach and the energy penalty associated with the disruption of the hydration shell of water molecules around the calcium carbonate core when the two particles approach. This is greatest for the sulfonate particle, which partially loses the surfactant ions to the solution, and least for the salicylate, which forms the weakest water "cage". The particles are separated by a water hydration layer, even at the point of closest approach.
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Affiliation(s)
- M S Bodnarchuk
- Department of Mechanical Engineering, Imperial College London , Exhibition Road, London SW7 2AZ, United Kingdom
| | - D Dini
- Department of Mechanical Engineering, Imperial College London , Exhibition Road, London SW7 2AZ, United Kingdom
| | - D M Heyes
- Department of Mechanical Engineering, Imperial College London , Exhibition Road, London SW7 2AZ, United Kingdom
| | - A Breakspear
- BP Technology Centre, Whitchurch Hill, Pangbourne RG8 7QR, United Kingdom
| | - S Chahine
- BP Technology Centre, Whitchurch Hill, Pangbourne RG8 7QR, United Kingdom
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81
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Krimmer SG, Cramer J, Schiebel J, Heine A, Klebe G. How Nothing Boosts Affinity: Hydrophobic Ligand Binding to the Virtually Vacated S1′ Pocket of Thermolysin. J Am Chem Soc 2017; 139:10419-10431. [DOI: 10.1021/jacs.7b05028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Stefan G. Krimmer
- Department of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Jonathan Cramer
- Department of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Johannes Schiebel
- Department of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Andreas Heine
- Department of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Gerhard Klebe
- Department of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
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82
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Cramer J, Krimmer SG, Heine A, Klebe G. Paying the Price of Desolvation in Solvent-Exposed Protein Pockets: Impact of Distal Solubilizing Groups on Affinity and Binding Thermodynamics in a Series of Thermolysin Inhibitors. J Med Chem 2017; 60:5791-5799. [DOI: 10.1021/acs.jmedchem.7b00490] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jonathan Cramer
- Institute of Pharmaceutical
Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Stefan G. Krimmer
- Institute of Pharmaceutical
Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Andreas Heine
- Institute of Pharmaceutical
Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Gerhard Klebe
- Institute of Pharmaceutical
Chemistry, University of Marburg, Marbacher Weg 6, 35032 Marburg, Germany
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83
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Weiß RG, Setny P, Dzubiella J. Principles for Tuning Hydrophobic Ligand–Receptor Binding Kinetics. J Chem Theory Comput 2017; 13:3012-3019. [DOI: 10.1021/acs.jctc.7b00216] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- R. Gregor Weiß
- Institut
für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin, Germany
- Institut
für Weiche Materie and Funktionale Materialen, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, D-14109 Berlin, Germany
| | - Piotr Setny
- Centre
of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Joachim Dzubiella
- Institut
für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin, Germany
- Institut
für Weiche Materie and Funktionale Materialen, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, D-14109 Berlin, Germany
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84
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Fox JM, Kang K, Sastry M, Sherman W, Sankaran B, Zwart PH, Whitesides GM. Water-Restructuring Mutations Can Reverse the Thermodynamic Signature of Ligand Binding to Human Carbonic Anhydrase. Angew Chem Int Ed Engl 2017; 56:3833-3837. [PMID: 28252841 DOI: 10.1002/anie.201609409] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/21/2016] [Indexed: 01/09/2023]
Abstract
This study uses mutants of human carbonic anhydrase (HCAII) to examine how changes in the organization of water within a binding pocket can alter the thermodynamics of protein-ligand association. Results from calorimetric, crystallographic, and theoretical analyses suggest that most mutations strengthen networks of water-mediated hydrogen bonds and reduce binding affinity by increasing the enthalpic cost and, to a lesser extent, the entropic benefit of rearranging those networks during binding. The organization of water within a binding pocket can thus determine whether the hydrophobic interactions in which it engages are enthalpy-driven or entropy-driven. Our findings highlight a possible asymmetry in protein-ligand association by suggesting that, within the confines of the binding pocket of HCAII, binding events associated with enthalpically favorable rearrangements of water are stronger than those associated with entropically favorable ones.
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Affiliation(s)
- Jerome M Fox
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA
| | - Kyungtae Kang
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA
| | - Madhavi Sastry
- Schrödinger, Sanali Infopark, 8-2-120/113 Banjara Hills, Hyderabad, 11937, Andhra Pradesh, India
| | - Woody Sherman
- Schrödinger, Inc., 120 West 45thStreet, New York, NY, 10036, USA
| | - Banumathi Sankaran
- Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Peter H Zwart
- Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - George M Whitesides
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA, 02138, USA
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85
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Fox JM, Kang K, Sastry M, Sherman W, Sankaran B, Zwart PH, Whitesides GM. Water‐Restructuring Mutations Can Reverse the Thermodynamic Signature of Ligand Binding to Human Carbonic Anhydrase. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201609409] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jerome M. Fox
- Department of Chemistry and Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
| | - Kyungtae Kang
- Department of Chemistry and Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
| | - Madhavi Sastry
- Schrödinger Sanali Infopark, 8-2-120/113 Banjara Hills Hyderabad 11937, Andhra Pradesh India
| | - Woody Sherman
- Schrödinger, Inc. 120 West 45thStreet New York NY 10036 USA
| | - Banumathi Sankaran
- Berkeley Center for Structural Biology Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Peter H. Zwart
- Berkeley Center for Structural Biology Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - George M. Whitesides
- Department of Chemistry and Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
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86
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Yu S, Schuchardt M, Tölle M, van der Giet M, Zidek W, Dzubiella J, Ballauff M. Interaction of human serum albumin with uremic toxins: a thermodynamic study. RSC Adv 2017. [DOI: 10.1039/c7ra02838e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Interaction of uremic toxins with HSA is studied by ITC and understood in terms of thermodynamic driving forces.
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Affiliation(s)
- Shun Yu
- Soft Matter and Functional Materials
- Helmholtz-Zentrum Berlin
- 14109 Berlin
- Germany
- Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine”
| | - Mirjam Schuchardt
- Medizinische Klinik für Nephrologie
- Universitätsmedizin Berlin
- Campus Benjamin Franklin
- 12203 Berlin
- Germany
| | - Markus Tölle
- Medizinische Klinik für Nephrologie
- Universitätsmedizin Berlin
- Campus Benjamin Franklin
- 12203 Berlin
- Germany
| | - Markus van der Giet
- Medizinische Klinik für Nephrologie
- Universitätsmedizin Berlin
- Campus Benjamin Franklin
- 12203 Berlin
- Germany
| | - Walter Zidek
- Medizinische Klinik für Nephrologie
- Universitätsmedizin Berlin
- Campus Benjamin Franklin
- 12203 Berlin
- Germany
| | - Joachim Dzubiella
- Soft Matter and Functional Materials
- Helmholtz-Zentrum Berlin
- 14109 Berlin
- Germany
- Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine”
| | - Matthias Ballauff
- Soft Matter and Functional Materials
- Helmholtz-Zentrum Berlin
- 14109 Berlin
- Germany
- Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine”
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87
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Gopal SM, Klumpers F, Herrmann C, Schäfer LV. Solvent effects on ligand binding to a serine protease. Phys Chem Chem Phys 2017; 19:10753-10766. [DOI: 10.1039/c6cp07899k] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ITC experiments and MD simulations reveal the mechanism behind enthalpy/entropy compensation upon trypsin-benzamidine binding at different solvation conditions.
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Affiliation(s)
- Srinivasa M. Gopal
- Center for Theoretical Chemistry
- Faculty of Chemistry and Biochemistry
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
| | - Fabian Klumpers
- Physical Chemistry I
- Faculty of Chemistry and Biochemistry
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
| | - Christian Herrmann
- Physical Chemistry I
- Faculty of Chemistry and Biochemistry
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
| | - Lars V. Schäfer
- Center for Theoretical Chemistry
- Faculty of Chemistry and Biochemistry
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
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88
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Kinoshita M, Hayashi T. Unified elucidation of the entropy-driven and -opposed hydrophobic effects. Phys Chem Chem Phys 2017; 19:25891-25904. [DOI: 10.1039/c7cp05160c] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The association of nonpolar solutes is generally believed to be entropy driven, which has been shown to be true for the contact of small molecules, ellipsoids, and plates.
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89
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Pal RK, Haider K, Kaur D, Flynn W, Xia J, Levy RM, Taran T, Wickstrom L, Kurtzman T, Gallicchio E. A combined treatment of hydration and dynamical effects for the modeling of host-guest binding thermodynamics: the SAMPL5 blinded challenge. J Comput Aided Mol Des 2017; 31:29-44. [PMID: 27696239 PMCID: PMC5477994 DOI: 10.1007/s10822-016-9956-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 08/25/2016] [Indexed: 01/02/2023]
Abstract
As part of the SAMPL5 blinded experiment, we computed the absolute binding free energies of 22 host-guest complexes employing a novel approach based on the BEDAM single-decoupling alchemical free energy protocol with parallel replica exchange conformational sampling and the AGBNP2 implicit solvation model specifically customized to treat the effect of water displacement as modeled by the Hydration Site Analysis method with explicit solvation. Initial predictions were affected by the lack of treatment of ionic charge screening, which is very significant for these highly charged hosts, and resulted in poor relative ranking of negatively versus positively charged guests. Binding free energies obtained with Debye-Hückel treatment of salt effects were in good agreement with experimental measurements. Water displacement effects contributed favorably and very significantly to the observed binding affinities; without it, the modeling predictions would have grossly underestimated binding. The work validates the implicit/explicit solvation approach employed here and it shows that comprehensive physical models can be effective at predicting binding affinities of molecular complexes requiring accurate treatment of conformational dynamics and hydration.
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Affiliation(s)
- Rajat Kumar Pal
- Department of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York, 11210, USA
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
| | - Kamran Haider
- Department of Chemistry, Lehman College, The City University of New York, 250 Bedford Park Blvd. West, Bronx, New York, NY, 10468, USA
| | - Divya Kaur
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
| | - William Flynn
- Center for Biophysics and Computational Biology, Institute of Computational Molecular Science and Department of Chemistry, Temple University, Philadelphia, PA, USA
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Junchao Xia
- Center for Biophysics and Computational Biology, Institute of Computational Molecular Science and Department of Chemistry, Temple University, Philadelphia, PA, USA
| | - Ronald M Levy
- Center for Biophysics and Computational Biology, Institute of Computational Molecular Science and Department of Chemistry, Temple University, Philadelphia, PA, USA
| | - Tetiana Taran
- Borough of Manhattan Community College, Department of Science, The City University of New York, 199 Chambers Street, New York, NY, 10007, USA
| | - Lauren Wickstrom
- Borough of Manhattan Community College, Department of Science, The City University of New York, 199 Chambers Street, New York, NY, 10007, USA
| | - Tom Kurtzman
- Department of Chemistry, Lehman College, The City University of New York, 250 Bedford Park Blvd. West, Bronx, New York, NY, 10468, USA
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
| | - Emilio Gallicchio
- Department of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York, 11210, USA.
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
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90
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Krimmer SG, Cramer J, Betz M, Fridh V, Karlsson R, Heine A, Klebe G. Rational Design of Thermodynamic and Kinetic Binding Profiles by Optimizing Surface Water Networks Coating Protein-Bound Ligands. J Med Chem 2016; 59:10530-10548. [DOI: 10.1021/acs.jmedchem.6b00998] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Stefan G. Krimmer
- Institute
of Pharmaceutical Chemistry, University of Marburg, Marbacher
Weg 6, 35032 Marburg, Germany
| | - Jonathan Cramer
- Institute
of Pharmaceutical Chemistry, University of Marburg, Marbacher
Weg 6, 35032 Marburg, Germany
| | - Michael Betz
- Institute
of Pharmaceutical Chemistry, University of Marburg, Marbacher
Weg 6, 35032 Marburg, Germany
| | - Veronica Fridh
- GE Healthcare Bio-Sciences AB, SE-751 84 Uppsala, Sweden
| | | | - Andreas Heine
- Institute
of Pharmaceutical Chemistry, University of Marburg, Marbacher
Weg 6, 35032 Marburg, Germany
| | - Gerhard Klebe
- Institute
of Pharmaceutical Chemistry, University of Marburg, Marbacher
Weg 6, 35032 Marburg, Germany
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91
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Nam GU, Bonifacio RG, Kwon JH, Hong Y. Kinetics and equilibrium partitioning of dissolved BTEX in PDMS and POM sheets. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:18901-18910. [PMID: 27335013 DOI: 10.1007/s11356-016-7098-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/13/2016] [Indexed: 06/06/2023]
Abstract
Passive sampling of volatile organic chemicals from soil and groundwater is primarily important in assessing the status of environmental contamination. A group of low molecular weight pollutants usually found in petroleum fuels, benzene, toluene, ethylbenzene, and xylenes (BTEX) was studied for its kinetics and equilibrium partitioning with single-phase passive samplers using polydimethylsiloxane (PDMS) and polyoxymethylene (POM) as sorbing phase. PDMS (1 mm) and POM (0.076 mm) sheets were used for sorption of BTEX and concentrations were analyzed using GC-FID. The equilibrium absorption and desorption of PDMS in water was achieved after 120 min while POM sheets absorbed up to 35 days and desorbed in 7 days. The kinetic rate constants in PDMS is higher than in POM up to 3 orders of magnitude. Logarithms of partition coefficient were determined to be in the range of 1.6-2.8 for PDMS and 2.1-3.1 for POM. The results indicate that POM is a stronger sorbent for BTEX and has slower equilibration time than PDMS. The partitioning process for both polymers was found to be enthalpy-driven by measurement of K d values at varying temperatures. K d values increase at low temperature and high ionic strength conditions. Presence of other gasoline components, as well as dissolved organic matter, did not significantly affect equilibrium partitioning. A good 1:1 correlation between the measured and the predicted concentrations was established on testing the potential application of the constructed PDMS sampler on natural soils and artificial soils spiked with gasoline-contaminated water.
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Affiliation(s)
- Go-Un Nam
- Department of Environmental Engineering, Daegu University, 201 Daegudae-ro, Gyeongsan-si, Gyeongsanbuk-do, 38453, Korea
| | - Riza Gabriela Bonifacio
- Department of Environmental Engineering, Daegu University, 201 Daegudae-ro, Gyeongsan-si, Gyeongsanbuk-do, 38453, Korea
| | - Jung-Hwan Kwon
- Division of Environmental Science and Ecological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Korea
| | - Yongseok Hong
- Department of Environmental Engineering, Daegu University, 201 Daegudae-ro, Gyeongsan-si, Gyeongsanbuk-do, 38453, Korea.
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92
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Djikaev Y, Ruckenstein E. Recent developments in the theoretical, simulational, and experimental studies of the role of water hydrogen bonding in hydrophobic phenomena. Adv Colloid Interface Sci 2016; 235:23-45. [PMID: 27312562 DOI: 10.1016/j.cis.2016.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 04/27/2016] [Accepted: 05/10/2016] [Indexed: 10/21/2022]
Abstract
Hydrophobic effects (hydrophobic hydration and hydrophobic interaction) constitute an important element of a wide variety of phenomena relevant to biological, physical, chemical, environmental, engineering, and pharmaceutical sciences, such as the immiscibility of oil and water, self-assembly of amphiphiles leading to micelle and membrane formation, folding and stability and unfolding of the native structure of a biologically active protein, gating of ion channels, wetting, froth floatation, and adhesion. On the other hand, the hydrogen bonding ability of water plays a major (if not crucial) role in hydrophobic phenomena. We present a review of most important and relatively recent experimental, simulational, and theoretical research on hydrophobic phenomena in various systems. With a particular interest we survey investigations clarifying the role of water hydrogen bonding therein, because it has been the main object of our own recent research. We have developed a probabilistic hydrogen bond (PHB) model that allows one to obtain an analytic expression for the number of bonds per water molecule as a function of its distance to a hydrophobe, hydrophobe radius, and temperature. Knowing that function, one can explicitly identify a water hydrogen bond contribution to the external potential whereto a water molecule is subjected near a hydrophobe. Combining the PHB model with the classical density functional theory (DFT), one can examine the contribution of water hydrogen bonding to the temperature and lengthscale effects on the hydration of particles and on their solvent-mediated interactions over the entire low-to-high temperature and small-to-large lengthscale ranges. We applied the combined DFT/PHB model to study a variety of hydrophobic phenomena such as (liquid) water in contact with a hydrophobic plate, solvation of spherical solutes of various radii in associated and non-associated liquids at various temperatures, the solvent-mediated interaction of spherical solutes and its temperature dependence, interaction of C60 fullerenes in water, temperature effect on the evaporation lengthscale of water confined between two hydrophobes, temperature dependence of the effective width of the solute-solvent transition layer and average density therein. These applications demonstrated that the DFT/PHB model can serve as a valuable tool in studying hydrophobic phenomena because it constitutes a balanced combination of simplicity, accuracy, and detail. The predictions of the combined DFT/PHB approach for the solvent density profiles and thermodynamic aspects of hydrophobic phenomena are generally in good agreement with experiments and simulations. For example, it predicts the small-to-large crossover lengthscale of its mechanism to be approximately in the range from 1nm to 4nm, and decreasing with increasing temperature. It also suggests that, in terms of the average fluid density in the solute-solvent transition layer, the transition layer for small hydrophobes (of radii ≲2 nm) becomes enriched with rather than depleted of fluid when both the solvent-solute affinity and hb-energy alteration ratio become large enough. The boundary values of these parameters, needed for the depletion-to-enrichment crossover, are predicted to decrease with increasing temperature.
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93
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Bodnarchuk MS. Water, water, everywhere… It's time to stop and think. Drug Discov Today 2016; 21:1139-46. [DOI: 10.1016/j.drudis.2016.05.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 04/15/2016] [Accepted: 05/13/2016] [Indexed: 12/11/2022]
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94
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Haider K, Wickstrom L, Ramsey S, Gilson MK, Kurtzman T. Enthalpic Breakdown of Water Structure on Protein Active-Site Surfaces. J Phys Chem B 2016; 120:8743-56. [PMID: 27169482 DOI: 10.1021/acs.jpcb.6b01094] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The principles underlying water reorganization around simple nonpolar solutes are well understood and provide the framework for the classical hydrophobic effect, whereby water molecules structure themselves around solutes so that they maintain favorable energetic contacts with both the solute and the other water molecules. However, for certain solute surface topographies, water molecules, due to their geometry and size, are unable to simultaneously maintain favorable energetic contacts with both the surface and neighboring water molecules. In this study, we analyze the solvation of ligand-binding sites for six structurally diverse proteins using hydration site analysis and measures of local water structure, in order to identify surfaces at which water molecules are unable to structure themselves in a way that maintains favorable enthalpy relative to bulk water. These surfaces are characterized by a high degree of enclosure, weak solute-water interactions, and surface constraints that induce unfavorable pair interactions between neighboring water molecules. Additionally, we find that the solvation of charged side chains in an active site generally results in favorable enthalpy but can also lead to pair interactions between neighboring water molecules that are significantly unfavorable relative to bulk water. We find that frustrated local structure can occur not only in apolar and weakly polar pockets, where overall enthalpy tends to be unfavorable, but also in charged pockets, where overall water enthalpy tends to be favorable. The characterization of local water structure in these terms may prove useful for evaluating the displacement of water from diverse protein active-site environments.
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Affiliation(s)
- Kamran Haider
- Department of Chemistry, Lehman College, The City University of New York , 250 Bedford Park Boulevard West, Bronx, New York 10468, United States
| | - Lauren Wickstrom
- Borough of Manhattan Community College, Department of Science, The City University of New York , 199 Chambers Street, New York, New York 10007, United States
| | - Steven Ramsey
- Department of Chemistry, Lehman College, The City University of New York , 250 Bedford Park Boulevard West, Bronx, New York 10468, United States.,Ph.D. Program in Biochemistry, The Graduate Center of The City University of New York , 365 Fifth Avenue, New York, New York 10016, United States
| | - Michael K Gilson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093-0736, United States
| | - Tom Kurtzman
- Department of Chemistry, Lehman College, The City University of New York , 250 Bedford Park Boulevard West, Bronx, New York 10468, United States.,Ph.D. Program in Biochemistry, The Graduate Center of The City University of New York , 365 Fifth Avenue, New York, New York 10016, United States.,Ph.D. Program in Chemistry, The Graduate Center of The City University of New York , 365 Fifth Avenue, New York, New York 10016, United States
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95
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Fong CW. The effect of desolvation on the binding of inhibitors to HIV-1 protease and cyclin-dependent kinases: Causes of resistance. Bioorg Med Chem Lett 2016; 26:3705-13. [PMID: 27317642 DOI: 10.1016/j.bmcl.2016.05.080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/23/2016] [Accepted: 05/27/2016] [Indexed: 11/17/2022]
Abstract
Studies of the cyclin-dependent kinase inhibitors and HIV-1 protease inhibitors have confirmed that ligand-protein binding is dependent on desolvation effects. It has been found that a four parameter linear model incorporating desolvation energy, lipophilicity, dipole moment and molecular volume of the ligands is a good model to describe the binding between ligands and kinases or proteases. The resistance shown by MDR proteases to the anti-viral drugs is multi-faceted involving varying changes in desolvation, lipophilicity and dipole moment interaction compared to the non-resistant protease. Desolvation has been shown to be the dominant factor influencing the effect of inhibitors against the cyclin-dependent kinases, but lipophilicity and dipole moment are also significant factors. The model can differentiate between the inhibitory activity of CDK2/cycE, CDK1/cycB and CDK4/cycD enzymes.
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Affiliation(s)
- Dor Ben-Amotz
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907;
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97
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Weiß RG, Setny P, Dzubiella J. Solvent Fluctuations Induce Non-Markovian Kinetics in Hydrophobic Pocket-Ligand Binding. J Phys Chem B 2016; 120:8127-36. [DOI: 10.1021/acs.jpcb.6b01219] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. Gregor Weiß
- Institut
für Physik, Humboldt-Universität zu Berlin, Newtonstrasse
15, D-12489 Berlin, Germany
- Institut
für Weiche Materie and Funktionale Materialen, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, D-14109 Berlin, Germany
| | - Piotr Setny
- Centre
of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Joachim Dzubiella
- Institut
für Physik, Humboldt-Universität zu Berlin, Newtonstrasse
15, D-12489 Berlin, Germany
- Institut
für Weiche Materie and Funktionale Materialen, Helmholtz-Zentrum Berlin, Hahn-Meitner Platz 1, D-14109 Berlin, Germany
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98
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Martin L, Bilek MM, Weiss AS, Kuyucak S. Force fields for simulating the interaction of surfaces with biological molecules. Interface Focus 2016; 6:20150045. [PMID: 26855748 PMCID: PMC4686237 DOI: 10.1098/rsfs.2015.0045] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The interaction of biomolecules with solid interfaces is of fundamental importance to several emerging biotechnologies such as medical implants, anti-fouling coatings and novel diagnostic devices. Many of these technologies rely on the binding of peptides to a solid surface, but a full understanding of the mechanism of binding, as well as the effect on the conformation of adsorbed peptides, is beyond the resolution of current experimental techniques. Nanoscale simulations using molecular mechanics offer potential insights into these processes. However, most models at this scale have been developed for aqueous peptide and protein simulation, and there are no proven models for describing biointerfaces. In this review, we detail the current research towards developing a non-polarizable molecular model for peptide-surface interactions, with a particular focus on fitting the model parameters as well as validation by choice of appropriate experimental data.
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Affiliation(s)
- Lewis Martin
- Department of Applied Physics, University of Sydney, Sydney, New South Wales, Australia
| | - Marcela M. Bilek
- Department of Applied Physics, University of Sydney, Sydney, New South Wales, Australia
| | - Anthony S. Weiss
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia
- Department of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
- Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
| | - Serdar Kuyucak
- Department of Applied Physics, University of Sydney, Sydney, New South Wales, Australia
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99
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Rehman AA, Ahsan H, Khan FH. Identification of a new alpha-2-macroglobulin: Multi-spectroscopic and isothermal titration calorimetry study. Int J Biol Macromol 2016; 83:366-75. [DOI: 10.1016/j.ijbiomac.2015.11.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/12/2015] [Accepted: 11/14/2015] [Indexed: 01/14/2023]
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100
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Nguyen CN, Kurtzman T, Gilson MK. Spatial Decomposition of Translational Water-Water Correlation Entropy in Binding Pockets. J Chem Theory Comput 2015; 12:414-29. [PMID: 26636620 PMCID: PMC4819442 DOI: 10.1021/acs.jctc.5b00939] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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A number
of computational tools available today compute the thermodynamic properties
of water at surfaces and in binding pockets by using inhomogeneous
solvation theory (IST) to analyze explicit-solvent simulations. Such
methods enable qualitative spatial mappings of both energy and entropy
around a solute of interest and can also be applied quantitatively.
However, the entropy estimates of existing methods have, to date,
been almost entirely limited to the first-order terms in the IST’s
entropy expansion. These first-order terms account for localization
and orientation of water molecules in the field of the solute but
not for the modification of water–water correlations by the
solute. Here, we present an extension of the Grid Inhomogeneous Solvation
Theory (GIST) approach which accounts for water–water translational
correlations. The method involves rewriting the two-point density
of water in terms of a conditional density and utilizes the efficient
nearest-neighbor entropy estimation approach. Spatial maps of this
second order term, for water in and around the synthetic host cucurbit[7]uril
and in the binding pocket of the enzyme Factor Xa, reveal mainly negative
contributions, indicating solute-induced water–water correlations
relative to bulk water; particularly strong signals are obtained for
sites at the entrances of cavities or pockets. This second-order term
thus enters with the same, negative, sign as the first order translational
and orientational terms. Numerical and convergence properties of the
methodology are examined.
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Affiliation(s)
- Crystal N Nguyen
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093-0736, United States
| | - Tom Kurtzman
- Department of Chemistry, Lehman College, The City University of New York , 250 Bedford Park Blvd. West, Bronx, New York, New York 10468, United States.,Ph.D. Program in Chemistry, The Graduate Center of The City University of New York , New York 10016, United States
| | - Michael K Gilson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego , 9500 Gilman Drive, La Jolla, California 92093-0736, United States
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