1
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Groaz E, Modranka J, Ploschik D, Jabgunde A, Froeyen M, Jang MY, Wagenknecht HA, Herdewijn P. Impact of sulfur substitution on biotin binding affinity to streptavidin. Bioorg Chem 2024; 150:107600. [PMID: 38945086 DOI: 10.1016/j.bioorg.2024.107600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/02/2024]
Abstract
In this study, we investigated how the replacement of the tetrahydrothiophene ring of biotin with either an oxolane or (methyl)pyrrolidine moiety may affect its molecular interactions, in an effort to identify alternative affinity ligands suitable for in vitro and in vivo applications in synthetic biology. Initial molecular dynamics (MD) simulations suggested the potential formation of a hydrogen bond between either the oxygen or nitrogen atom of the envisaged tetrahydroheteryl analogues and the Thr90 residue of streptavidin, mirroring the sulfur-centered hydrogen bond detected by the crystallographic analysis of the biotin-streptavidin interaction. Therefore, oxy-, aza-, and N-methylazabiotin were readily synthesized starting from chiral five- or six-carbon sugar precursors. Based on fluorescence-based titration experiments using the corresponding fluorescein conjugates, oxybiotin showed a binding behavior similar to biotin with streptavidin, while both amino analogues displayed lower binding capacities. Notably, azabiotin exhibited a pH-dependent interaction profile, demonstrating enhanced binding under acidic conditions but weaker binding under basic pH, which could be exploited for various purposes.
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Affiliation(s)
- Elisabetta Groaz
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Jakub Modranka
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Damian Ploschik
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Amit Jabgunde
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Mathy Froeyen
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Mi-Yeon Jang
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Hans-Achim Wagenknecht
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Piet Herdewijn
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
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2
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Wei X, Chen C, Popov AV, Bathe M, Hernandez R. Binding Site Programmable Self-Assembly of 3D Hierarchical DNA Origami Nanostructures. J Phys Chem A 2024; 128:4999-5008. [PMID: 38875485 DOI: 10.1021/acs.jpca.4c02603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2024]
Abstract
DNA nanotechnology has broad applications in biomedical drug delivery and programmable materials. Characterization of the self-assembly of DNA origami and quantum dots (QDs) is necessary for the development of new DNA-based nanostructures. We use computation and experiment to show that the self-assembly of 3D hierarchical nanostructures can be controlled by programming the binding site number and their positions on DNA origami. Using biotinylated pentagonal pyramid wireframe DNA origamis and streptavidin capped QDs, we demonstrate that DNA origami with 1 binding site at the outer vertex can assemble multimeric origamis with up to 6 DNA origamis on 1 QD, and DNA origami with 1 binding site at the inner center can only assemble monomeric and dimeric origamis. Meanwhile, the yield percentages of different multimeric origamis are controlled by the QD:DNA-origami stoichiometric mixing ratio. DNA origamis with 2 binding sites at the αγ positions (of the pentagon) make larger nanostructures than those with binding sites at the αβ positions. In general, increasing the number of binding sites leads to increases in the nanostructure size. At high DNA origami concentration, the QD number in each cluster becomes the limiting factor for the growth of nanostructures. We find that reducing the QD size can also affect the self-assembly because of the reduced access to the binding sites from more densely packed origamis.
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Affiliation(s)
- Xingfei Wei
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Chi Chen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alexander V Popov
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Mark Bathe
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Rigoberto Hernandez
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
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3
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Boresch S. On Analytical Corrections for Restraints in Absolute Binding Free Energy Calculations. J Chem Inf Model 2024; 64:3605-3609. [PMID: 38640478 PMCID: PMC11094717 DOI: 10.1021/acs.jcim.4c00442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 04/21/2024]
Abstract
Double decoupling absolute binding free energy simulations require an intermediate state at which the ligand is held solely by restraints in a position and orientation resembling the bound state. One possible choice consists of one distance, two angle, and three dihedral angle restraints. Here, I demonstrate that in practically all cases the analytical correction derived under the rigid rotator harmonic oscillator approximation is sufficient to account for the free energy of the restraints.
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Affiliation(s)
- Stefan Boresch
- Department of Chemistry, University
of Vienna, Währinger
Straße 17, A-1090 Vienna, Austria
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4
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Clark F, Robb G, Cole DJ, Michel J. Comparison of Receptor-Ligand Restraint Schemes for Alchemical Absolute Binding Free Energy Calculations. J Chem Theory Comput 2023; 19:3686-3704. [PMID: 37285579 PMCID: PMC10308817 DOI: 10.1021/acs.jctc.3c00139] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Indexed: 06/09/2023]
Abstract
Alchemical absolute binding free energy calculations are of increasing interest in drug discovery. These calculations require restraints between the receptor and ligand to restrict their relative positions and, optionally, orientations. Boresch restraints are commonly used, but they must be carefully selected in order to sufficiently restrain the ligand and to avoid inherent instabilities. Applying multiple distance restraints between anchor points in the receptor and ligand provides an alternative framework without inherent instabilities which may provide convergence benefits by more strongly restricting the relative movements of the receptor and ligand. However, there is no simple method to calculate the free energy of releasing these restraints due to the coupling of the internal and external degrees of freedom of the receptor and ligand. Here, a method to rigorously calculate free energies of binding with multiple distance restraints by imposing intramolecular restraints on the anchor points is proposed. Absolute binding free energies for the human macrophage migration inhibitory factor/MIF180, system obtained using a variety of Boresch restraints and rigorous and nonrigorous implementations of multiple distance restraints are compared. It is shown that several multiple distance restraint schemes produce estimates in good agreement with Boresch restraints. In contrast, calculations without orientational restraints produce erroneously favorable free energies of binding by up to approximately 4 kcal mol-1. These approaches offer new options for the deployment of alchemical absolute binding free energy calculations.
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Affiliation(s)
- Finlay Clark
- EaStCHEM
School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Graeme Robb
- Oncology
R&D, AstraZeneca, Cambridge CB4 0WG, United Kingdom
| | - Daniel J. Cole
- School
of Natural and Environmental Sciences, Newcastle
University, Newcastle
upon Tyne NE1 7RU, United Kingdom
| | - Julien Michel
- EaStCHEM
School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
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5
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Park H, Sut TN, Ferhan AR, Yoon BK, Zhdanov VP, Cho NJ, Jackman JA. pH-Modulated Nanoarchitectonics for Enhancement of Multivalency-Induced Vesicle Shape Deformation at Receptor-Presenting Lipid Membrane Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37267480 DOI: 10.1021/acs.langmuir.3c00777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Multivalent ligand-receptor interactions between receptor-presenting lipid membranes and ligand-modified biological and biomimetic nanoparticles influence cellular entry and fusion processes. Environmental pH changes can drive these membrane-related interactions by affecting membrane nanomechanical properties. Quantitatively, however, the corresponding effects on high-curvature, sub-100 nm lipid vesicles are scarcely understood, especially in the multivalent binding context. Herein, we employed the label-free localized surface plasmon resonance (LSPR) sensing technique to track the multivalent attachment kinetics, shape deformation, and surface coverage of biotin ligand-functionalized, zwitterionic lipid vesicles with different ligand densities on a streptavidin receptor-coated supported lipid bilayer under varying pH conditions (4.5, 6, 7.5). Our results demonstrate that more extensive multivalent interactions caused greater vesicle shape deformation across the tested pH conditions, which affected vesicle surface packing as well. Notably, there were also pH-specific differences, i.e., a higher degree of vesicle shape deformation was triggered at a lower multivalent binding energy in pH 4.5 than in pH 6 and 7.5 conditions. These findings support that the nanomechanical properties of high-curvature lipid membranes, especially the membrane bending energy and the corresponding responsiveness to multivalent binding interactions, are sensitive to solution pH, and indicate that multivalency-induced vesicle shape deformation occurs slightly more readily in acidic pH conditions relevant to biological environments.
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Affiliation(s)
- Hyeonjin Park
- School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Drive, 637553 Singapore
| | - Tun Naw Sut
- School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Abdul Rahim Ferhan
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Drive, 637553 Singapore
| | - Bo Kyeong Yoon
- School of Healthcare and Biomedical Engineering, Chonnam National University, Yeosu 59626, Republic of Korea
| | - Vladimir P Zhdanov
- Division of Nano and Biophysics, Department of Physics, Chalmers University of Technology, Gothenburg 41296, Sweden
- Boreskov Institute of Catalysis, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Drive, 637553 Singapore
| | - Joshua A Jackman
- School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
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6
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Eberhardt J, Forli S. WaterKit: Thermodynamic Profiling of Protein Hydration Sites. J Chem Theory Comput 2023; 19:2535-2556. [PMID: 37094087 PMCID: PMC10732097 DOI: 10.1021/acs.jctc.2c01087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Water desolvation is one of the key components of the free energy of binding of small molecules to their receptors. Thus, understanding the energetic balance of solvation and desolvation resulting from individual water molecules can be crucial when estimating ligand binding, especially when evaluating different molecules and poses as done in High-Throughput Virtual Screening (HTVS). Over the most recent decades, several methods were developed to tackle this problem, ranging from fast approximate methods (usually empirical functions using either discrete atom-atom pairwise interactions or continuum solvent models) to more computationally expensive and accurate ones, mostly based on Molecular Dynamics (MD) simulations, such as Grid Inhomogeneous Solvation Theory (GIST) or Double Decoupling. On one hand, MD-based methods are prohibitive to use in HTVS to estimate the role of waters on the fly for each ligand. On the other hand, fast and approximate methods show an unsatisfactory level of accuracy, with low agreement with results obtained with the more expensive methods. Here we introduce WaterKit, a new grid-based sampling method with explicit water molecules to calculate thermodynamic properties using the GIST method. Our results show that the discrete placement of water molecules is successful in reproducing the position of crystallographic waters with very high accuracy, as well as providing thermodynamic estimates with accuracy comparable to more expensive MD simulations. Unlike these methods, WaterKit can be used to analyze specific regions on the protein surface, (such as the binding site of a receptor), without having to hydrate and simulate the whole receptor structure. The results show the feasibility of a general and fast method to compute thermodynamic properties of water molecules, making it well-suited to be integrated in high-throughput pipelines such as molecular docking.
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Affiliation(s)
- Jerome Eberhardt
- Department of Integrative Structural and Computational Biology, Scripps Research, La Jolla, California 92037, United States
| | - Stefano Forli
- Department of Integrative Structural and Computational Biology, Scripps Research, La Jolla, California 92037, United States
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7
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Majumder A, Kwon S, Straub JE. On Computing Equilibrium Binding Constants for Protein-Protein Association in Membranes. J Chem Theory Comput 2022; 18:3961-3971. [PMID: 35580264 PMCID: PMC11260346 DOI: 10.1021/acs.jctc.2c00106] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein association in lipid membranes is fundamental to membrane protein function and of great biomedical relevance. All-atom and coarse-grained models have been extensively used to understand the protein-protein interactions in the membrane and to compute equilibrium association constants. However, slow translational and rotational diffusion of protein in membrane presents challenges to the effective sampling of conformations defining the ensembles of free and bound states contributing to the association equilibrium and the free energy of dimerization. We revisit the homodimerization equilibrium of the TM region of glycophorin A. Conformational sampling is performed using umbrella sampling along previously proposed one-dimensional collective variables and compared with sampling over a two-dimensional collective variable space using the MARTINI v2.2 force field. We demonstrate that the one-dimensional collective variables suffer from restricted sampling of the native homodimer conformations leading to a biased free energy landscape. Conversely, simulations along the two-dimensional collective variable effectively characterize the thermodynamically relevant native and non-native interactions contributing to the association equilibrium. These results demonstrate the challenges associated with accurately characterizing binding equilibria when multiple poses contribute to the bound state ensemble.
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Affiliation(s)
- Ayan Majumder
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Seulki Kwon
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - John E Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
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8
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Basu S, Huynh L, Zhang S, Rabara R, Nguyen H, Velásquez Guzmán J, Hao G, Miles G, Shi Q, Stover E, Gupta G. Two Liberibacter Proteins Combine to Suppress Critical Innate Immune Defenses in Citrus. FRONTIERS IN PLANT SCIENCE 2022; 13:869178. [PMID: 35586217 PMCID: PMC9108871 DOI: 10.3389/fpls.2022.869178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/04/2022] [Indexed: 06/15/2023]
Abstract
We adopted a systems-based approach to determine the role of two Candidatus Liberibacter asiaticus (CLas) proteins, LasP 235 and Effector 3, in Huanglongbing (HLB) pathogenesis. While a published work suggests the involvement of these CLas proteins HLB pathogenesis, the exact structure-based mechanism of their action has not been elucidated. We conducted the following experiments to determine the structure-based mechanisms of action. First, we immunoprecipitated the interacting citrus protein partners of LasP 235 and Effector 3 from the healthy and CLas-infected Hamlin extracts and identified them by Liquid Chromatography with tandem mass spectrometry (LC-MS/MS). Second, we performed a split green fluorescent protein (GFP) assay in tobacco to validate that the interactions observed in vitro are also retained in planta. The notable in planta citrus targets of LasP 235 and Effector 3 include citrus innate immune proteins. Third, in vitro and in planta studies were performed to show that LasP 235 and Effector 3 interact with and inhibit the functions of multiple citrus proteins belonging to the innate immune pathways. These inhibitory interactions led to a high level of reactive oxygen species, blocking of bactericidal lipid transfer protein (LTP), and induction of premature programed cell death (PCD), all of which are beneficial to CLas lifecycle and HLB pathogenesis. Finally, we performed molecular dynamics simulations to visualize the interactions of LasP 235 and Effector 3, respectively, with LTP and Kunitz protease inhibitor. This led to the design of an LTP mimic, which sequestered and blocked LasP 235 and rescued the bactericidal activity of LTP thereby proving that LasP 235 , indeed, participates in HLB pathogenesis.
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Affiliation(s)
- Supratim Basu
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | - Loan Huynh
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | - Shujian Zhang
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | - Roel Rabara
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | - Hau Nguyen
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | | | - Guixia Hao
- Horticulture and Breeding, U. S. Horticultural Research Laboratory, Fort Pierce, FL, United States
| | - Godfrey Miles
- Horticulture and Breeding, U. S. Horticultural Research Laboratory, Fort Pierce, FL, United States
| | - Qingchun Shi
- Horticulture and Breeding, U. S. Horticultural Research Laboratory, Fort Pierce, FL, United States
| | - Ed Stover
- Horticulture and Breeding, U. S. Horticultural Research Laboratory, Fort Pierce, FL, United States
| | - Goutam Gupta
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
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9
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Qian S, Chang D, He S, Li Y. Aptamers from random sequence space: Accomplishments, gaps and future considerations. Anal Chim Acta 2022; 1196:339511. [DOI: 10.1016/j.aca.2022.339511] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/12/2022] [Accepted: 01/15/2022] [Indexed: 02/07/2023]
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10
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Ayan E, Yuksel B, Destan E, Ertem FB, Yildirim G, Eren M, Yefanov OM, Barty A, Tolstikova A, Ketawala GK, Botha S, Dao EH, Hayes B, Liang M, Seaberg MH, Hunter MS, Batyuk A, Mariani V, Su Z, Poitevin F, Yoon CH, Kupitz C, Cohen A, Doukov T, Sierra RG, Dağ Ç, DeMirci H. Cooperative allostery and structural dynamics of streptavidin at cryogenic- and ambient-temperature. Commun Biol 2022; 5:73. [PMID: 35058563 PMCID: PMC8776744 DOI: 10.1038/s42003-021-02903-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/28/2021] [Indexed: 11/11/2022] Open
Abstract
Multimeric protein assemblies are abundant in nature. Streptavidin is an attractive protein that provides a paradigm system to investigate the intra- and intermolecular interactions of multimeric protein complexes. Also, it offers a versatile tool for biotechnological applications. Here, we present two apo-streptavidin structures, the first one is an ambient temperature Serial Femtosecond X-ray crystal (Apo-SFX) structure at 1.7 Å resolution and the second one is a cryogenic crystal structure (Apo-Cryo) at 1.1 Å resolution. These structures are mostly in agreement with previous structural data. Combined with computational analysis, these structures provide invaluable information about structural dynamics of apo streptavidin. Collectively, these data further reveal a novel cooperative allostery of streptavidin which binds to substrate via water molecules that provide a polar interaction network and mimics the substrate biotin which displays one of the strongest affinities found in nature.
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Affiliation(s)
- Esra Ayan
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Busra Yuksel
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Ebru Destan
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Fatma Betul Ertem
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Gunseli Yildirim
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Meryem Eren
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | | | - Anton Barty
- Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607, Hamburg, Germany
| | | | - Gihan K Ketawala
- Department of Physics, Arizona State University, Tempe, AZ, 85287-1504, USA
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, 85287-5001, USA
| | - Sabine Botha
- Department of Physics, Arizona State University, Tempe, AZ, 85287-1504, USA
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, 85287-5001, USA
| | - E Han Dao
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, CA, 94025, USA
| | - Brandon Hayes
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Mengning Liang
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Matthew H Seaberg
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Mark S Hunter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Alexander Batyuk
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Valerio Mariani
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Zhen Su
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Frederic Poitevin
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Chun Hong Yoon
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Christopher Kupitz
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Aina Cohen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Tzanko Doukov
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Raymond G Sierra
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Çağdaş Dağ
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
- Nanofabrication and Nanocharacterization Center for Scientific and Technological Advanced Research, Koc University, 34450, Istanbul, Turkey
- Koc University Isbank Center for Infectious Diseases (KUISCID), 34010, Istanbul, Turkey
| | - Hasan DeMirci
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey.
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, CA, 94025, USA.
- Koc University Isbank Center for Infectious Diseases (KUISCID), 34010, Istanbul, Turkey.
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11
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Chen S, He Y, Geng Y, Wang Z, Han L, Han W. Molecular Dynamic Simulations of Bromodomain and Extra-Terminal Protein 4 Bonded to Potent Inhibitors. Molecules 2021; 27:molecules27010118. [PMID: 35011350 PMCID: PMC8747027 DOI: 10.3390/molecules27010118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/22/2021] [Accepted: 12/22/2021] [Indexed: 11/16/2022] Open
Abstract
Bromodomain and extra-terminal domain (BET) subfamily is the most studied subfamily of bromodomain-containing proteins (BCPs) family which can modulate acetylation signal transduction and produce diverse physiological functions. Thus, the BET family can be treated as an alternative strategy for targeting androgen-receptor (AR)-driven cancers. In order to explore the effect of inhibitors binding to BRD4 (the most studied member of BET family), four 150 ns molecular dynamic simulations were performed (free BRD4, Cpd4-BRD4, Cpd9-BRD4 and Cpd19-BRD4). Docking studies showed that Cpd9 and Cpd19 were located at the active pocket, as well as Cpd4. Molecular dynamics (MD) simulations indicated that only Cpd19 binding to BRD4 can induce residue Trp81-Ala89 partly become α-helix during MD simulations. MM-GBSA calculations suggested that Cpd19 had the best binding effect with BRD4 followed by Cpd4 and Cpd9. Computational alanine scanning results indicated that mutations in Phe83 made the greatest effects in Cpd9-BRD4 and Cpd19-BRD4 complexes, showing that Phe83 may play crucial roles in Cpd9 and Cpd19 binding to BRD4. Our results can provide some useful clues for further BCPs family search.
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Affiliation(s)
| | | | | | | | - Lu Han
- Correspondence: (L.H.); (W.H.)
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12
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Abstract
At the heart of drug design is the discovery of molecules that bind with high affinity to their drug targets. Biotin forms the strongest known noncovalent ligand-protein interactions with avidin and streptavidin, achieving femtomolar and picomolar affinities, respectively. This is made even more exceptional because biotin achieves this with a meagre molecular weight of 240 Da. Surprisingly, the approaches by which biotin achieves this are not in the standard repertoire of current medicinal chemistry practice. Biotin's biggest lesson is the importance of nonclassical H-bonds in protein-ligand complexes. Most of biotin's affinity stems from its flexible valeric acid side chain that forms CH-π, CH-O, and classical H-bonds with the lipophilic region of the binding pocket. Biotin also utilizes an oxyanion hole, a sulfur-centered H-bond, and water solvation in the bound state to achieve its potency. The facets and advantages of biotin's approach to binding should be more widely adopted in drug design.
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Affiliation(s)
- Darryl B McConnell
- Discovery Research, Boehringer Ingelheim Regional Center Vienna GmbH & Co KG, 1120 Vienna, Austria
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13
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Andújar SA, Gutiérrez LJ, Enriz RD, Baldoni HA. Structure, interface stability and hot-spots identification for RBD(SARS-CoV-2):hACE2 complex formation. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1979229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Sebastián A. Andújar
- Faculty of Chemistry, Biochemistry and Pharmacy, Multidisciplinary Institute of Biological Research (IMIBIO-SL. CONICET), National University of San Luis, San Luis, Argentina
| | - Lucas J. Gutiérrez
- Faculty of Chemistry, Biochemistry and Pharmacy, Multidisciplinary Institute of Biological Research (IMIBIO-SL. CONICET), National University of San Luis, San Luis, Argentina
| | - Ricardo D. Enriz
- Faculty of Chemistry, Biochemistry and Pharmacy, Multidisciplinary Institute of Biological Research (IMIBIO-SL. CONICET), National University of San Luis, San Luis, Argentina
| | - Héctor A. Baldoni
- Faculty of Chemistry, Biochemistry and Pharmacy, Institute of Applied Mathematics of San Luis (IMASL. CONICET), National University of San Luis, San Luis, Argentina
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14
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Duboué-Dijon E, Hénin J. Building intuition for binding free energy calculations: Bound state definition, restraints, and symmetry. J Chem Phys 2021; 154:204101. [PMID: 34241173 DOI: 10.1063/5.0046853] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The theory behind computation of absolute binding free energies using explicit-solvent molecular simulations is well-established, yet somewhat complex, with counter-intuitive aspects. This leads to frequent frustration, common misconceptions, and sometimes erroneous numerical treatment. To improve this, we present the main practically relevant segments of the theory with constant reference to physical intuition. We pinpoint the role of the implicit or explicit definition of the bound state (or the binding site) to make a robust link between an experimental measurement and a computational result. We clarify the role of symmetry and discuss cases where symmetry number corrections have been misinterpreted. In particular, we argue that symmetry corrections as classically presented are a source of confusion and could be advantageously replaced by restraint free energy contributions. We establish that contrary to a common intuition, partial or missing sampling of some modes of symmetric bound states does not affect the calculated decoupling free energies. Finally, we review these questions and pitfalls in the context of a few common practical situations: binding to a symmetric receptor (equivalent binding sites), binding of a symmetric ligand (equivalent poses), and formation of a symmetric complex, in the case of homodimerization.
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Affiliation(s)
- E Duboué-Dijon
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - J Hénin
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, 75005 Paris, France
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15
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Zhang L, Domeniconi G, Yang CC, Kang SG, Zhou R, Cong G. CASTELO: clustered atom subtypes aided lead optimization-a combined machine learning and molecular modeling method. BMC Bioinformatics 2021; 22:338. [PMID: 34157976 PMCID: PMC8218488 DOI: 10.1186/s12859-021-04214-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/18/2021] [Indexed: 01/18/2023] Open
Abstract
Background Drug discovery is a multi-stage process that comprises two costly major steps: pre-clinical research and clinical trials. Among its stages, lead optimization easily consumes more than half of the pre-clinical budget. We propose a combined machine learning and molecular modeling approach that partially automates lead optimization workflow in silico, providing suggestions for modification hot spots. Results The initial data collection is achieved with physics-based molecular dynamics simulation. Contact matrices are calculated as the preliminary features extracted from the simulations. To take advantage of the temporal information from the simulations, we enhanced contact matrices data with temporal dynamism representation, which are then modeled with unsupervised convolutional variational autoencoder (CVAE). Finally, conventional and CVAE-based clustering methods are compared with metrics to rank the submolecular structures and propose potential candidates for lead optimization. Conclusion With no need for extensive structure-activity data, our method provides new hints for drug modification hotspots which can be used to improve drug potency and reduce the lead optimization time. It can potentially become a valuable tool for medicinal chemists. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04214-4.
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Affiliation(s)
- Leili Zhang
- IBM Thomas J. Watson Research Center, 1101 Kitchawan Rd, 10598, Yorktown Heights, NY, USA.
| | - Giacomo Domeniconi
- IBM Thomas J. Watson Research Center, 1101 Kitchawan Rd, 10598, Yorktown Heights, NY, USA.
| | - Chih-Chieh Yang
- IBM Thomas J. Watson Research Center, 1101 Kitchawan Rd, 10598, Yorktown Heights, NY, USA
| | - Seung-Gu Kang
- IBM Thomas J. Watson Research Center, 1101 Kitchawan Rd, 10598, Yorktown Heights, NY, USA
| | - Ruhong Zhou
- ZheJiang University, 688 Yuhangtang Road, Hangzhou, 310027, China
| | - Guojing Cong
- Oak Ridge national laboratory, 1 Bethel Valley Rd, 37830, Oak Ridge, TN, USA
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16
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Yamamoto Y, Kominami H, Kobayashi K, Yamada H. Surface charge density measurement of a single protein molecule with a controlled orientation by AFM. Biophys J 2021; 120:2490-2497. [PMID: 33901471 PMCID: PMC8390862 DOI: 10.1016/j.bpj.2021.04.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/18/2021] [Accepted: 04/16/2021] [Indexed: 10/21/2022] Open
Abstract
The spatial distribution of functional groups causes a charge distribution that often has a close relationship with its biofunctions. To understand them of the protein molecules, measurements of the charge distribution under physiological conditions are desired. Atomic force microscopy (AFM) has been utilized to measure the surface charge density by measuring the electric double layer (EDL) force caused by the overlap of the EDLs on the surfaces of the AFM tip and the biomolecule. Here, we demonstrated the surface charge density measurement of a single streptavidin (SA) protein molecule by the three-dimensional force mapping method based on frequency modulation AFM (FM-AFM). The SA has a strong affinity to biotin because of the electrostatic interactions between the molecules. Therefore, the surface charge density measurements of the biotin-binding sites and other surface areas of the molecule have been anticipated. However, the surface charge density of the surfaces other than the biotin-binding side has never been measured. We demonstrate the surface charge density measurement of the top surface of the single SA molecule, which is perpendicular to the biotin-binding sides, with a controlled orientation using DNA origami as a template by FM-AFM in an electrolyte solution. The surface charge density of the top surface of the SA molecule was estimated by fitting the experimental force curves to the Derjaguin-Landau-Verwey-Overbeck theory. We found that the surface charge density of the top surface of the SA molecule is comparable to those reported earlier for the biotin-binding sides of the molecule. We expect that, by using the DNA origami technology, one can control the orientation of a biomolecule attached to the substrate and measure the surface charge density of the specific surface areas of the biomolecule to obtain information that will help us to understand the relationship between their structures and functions.
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Affiliation(s)
- Yuki Yamamoto
- Department of Electronic Science and Engineering, Kyoto University, Katsura, Kyoto, Japan.
| | - Hiroaki Kominami
- Department of Electronic Science and Engineering, Kyoto University, Katsura, Kyoto, Japan
| | - Kei Kobayashi
- Department of Electronic Science and Engineering, Kyoto University, Katsura, Kyoto, Japan
| | - Hirofumi Yamada
- Department of Electronic Science and Engineering, Kyoto University, Katsura, Kyoto, Japan
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17
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Rocha-Santos A, Chaves EJ, Grillo IB, de Freitas AS, Araújo DAM, Rocha GB. Thermochemical and Quantum Descriptor Calculations for Gaining Insight into Ricin Toxin A (RTA) Inhibitors. ACS OMEGA 2021; 6:8764-8777. [PMID: 33842748 PMCID: PMC8027999 DOI: 10.1021/acsomega.0c02588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 12/30/2020] [Indexed: 05/03/2023]
Abstract
In this work, we performed a study to assess the interactions between the ricin toxin A (RTA) subunit of ricin and some of its inhibitors using modern semiempirical quantum chemistry and ONIOM quantum mechanics/molecular mechanics (QM/MM) methods. Two approaches were followed (calculation of binding enthalpies, ΔH bind, and reactivity quantum chemical descriptors) and compared with the respective half-maximal inhibitory concentration (IC50) experimental data, to gain insight into RTA inhibitors and verify which quantum chemical method would better describe RTA-ligand interactions. The geometries for all RTA-ligand complexes were obtained after running classical molecular dynamics simulations in aqueous media. We found that single-point energy calculations of ΔH bind with the PM6-DH+, PM6-D3H4, and PM7 semiempirical methods and ONIOM QM/MM presented a good correlation with the IC50 data. We also observed, however, that the correlation decreased significantly when we calculated ΔH bind after full-atom geometry optimization with all semiempirical methods. Based on the results from reactivity descriptors calculations for the cases studied, we noted that both types of interactions, molecular overlap and electrostatic interactions, play significant roles in the overall affinity of these ligands for the RTA binding pocket.
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Affiliation(s)
- Acassio Rocha-Santos
- Department
of Chemistry, Federal University of Paraíba, Cidade Universitária, João Pessoa, PB 58051-900, Brazil
| | - Elton José
Ferreira Chaves
- Department
of Biotechnology, Federal University of
Paraíba, Cidade Universitária, João Pessoa, PB 58051-900, Brazil
| | - Igor Barden Grillo
- Department
of Chemistry, Federal University of Paraíba, Cidade Universitária, João Pessoa, PB 58051-900, Brazil
| | - Amanara Souza de Freitas
- Department
of Chemical Engineering, Federal University
of Paraíba, Cidade Universitária, João Pessoa, PB 58051-900, Brazil
| | | | - Gerd Bruno Rocha
- Department
of Chemistry, Federal University of Paraíba, Cidade Universitária, João Pessoa, PB 58051-900, Brazil
- . Phone/Fax: +55-83-3216-7437
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18
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Long MJC, Wang L, Aye Y. Getting the Right Grip? How Understanding Electrophile Selectivity Profiles Could Illuminate Our Understanding of Redox Signaling. Antioxid Redox Signal 2020; 33:1077-1091. [PMID: 31578876 PMCID: PMC7583342 DOI: 10.1089/ars.2019.7894] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Significance: Electrophile signaling is coming into focus as a bona fide cell signaling mechanism. The electrophilic regulation occurs typically through a sensing event (i.e., labeling of a protein) and a signaling event (the labeling event having an effect of the proteins activity, association, etc.). Recent Advances: Herein, we focus on the first step of this process, electrophile sensing. Electrophile sensing is typically a deceptively simple reaction between the thiol of a protein cysteine, of which there are around 200,000 in the human proteome, and a Michael acceptor, of which there are numerous flavors, including enals and enones. Recent data overall paint a picture that despite being a simple chemical reaction, electrophile sensing is a discerning process, showing labeling preferences that are often not in line with reactivity of the electrophile. Critical Issues: With a view to trying to decide what brings about highly electrophile-reactive protein cysteines, and how reactive these sensors may be, we discuss aspects of the thermodynamics and kinetics of covalent/noncovalent binding. Data made available by several laboratories indicate that it is likely that specific proteins exhibit highly stereo- and chemoselective electrophile sensing, which we take as good evidence for recognition between the electrophile and the protein before forming a covalent bond. Future Directions: We propose experiments that could help us gain a better and more quantitative understanding of the mechanisms through which sensing comes about. We further extoll the importance of performing more detailed experiments on labeling and trying to standardize the way we assess protein-specific electrophile sensing.
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Affiliation(s)
- Marcus J C Long
- 47 Pudding Gate, Bishop Burton, Beverley East Riding of Yorkshire, United Kingdom
| | - Lingxi Wang
- Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Yimon Aye
- Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
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19
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Song LF, Merz KM. Evolution of Alchemical Free Energy Methods in Drug Discovery. J Chem Inf Model 2020; 60:5308-5318. [DOI: 10.1021/acs.jcim.0c00547] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Lin Frank Song
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Kenneth M. Merz
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
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20
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Wang DD, Zhu M, Yan H. Computationally predicting binding affinity in protein-ligand complexes: free energy-based simulations and machine learning-based scoring functions. Brief Bioinform 2020; 22:5860693. [PMID: 32591817 DOI: 10.1093/bib/bbaa107] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 04/20/2020] [Accepted: 05/05/2020] [Indexed: 12/18/2022] Open
Abstract
Accurately predicting protein-ligand binding affinities can substantially facilitate the drug discovery process, but it remains as a difficult problem. To tackle the challenge, many computational methods have been proposed. Among these methods, free energy-based simulations and machine learning-based scoring functions can potentially provide accurate predictions. In this paper, we review these two classes of methods, following a number of thermodynamic cycles for the free energy-based simulations and a feature-representation taxonomy for the machine learning-based scoring functions. More recent deep learning-based predictions, where a hierarchy of feature representations are generally extracted, are also reviewed. Strengths and weaknesses of the two classes of methods, coupled with future directions for improvements, are comparatively discussed.
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Affiliation(s)
- Debby D Wang
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology
| | - Mengxu Zhu
- Department of Electrical Engineering, City University of Hong Kong
| | - Hong Yan
- College of Science and Engineering, City University of Hong Kong
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21
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Chen LY. Thermodynamic Integration in 3n Dimensions without Biases or Alchemy for Protein Interactions. FRONTIERS IN PHYSICS 2020; 8:202. [PMID: 32542181 PMCID: PMC7295167 DOI: 10.3389/fphy.2020.00202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Thermodynamic integration (TI), a powerful formalism for computing Gibbs free energy, has been implemented for many biophysical processes with alchemical schemes that require delicate human efforts to choose/design biasing potentials for sampling the desired biophysical events and to remove their artifactitious consequences afterwards. Theoretically, an alchemical scheme is exact but practically, an unsophisticated implementation of this exact formula can cause error amplifications. Small relative errors in the input parameters can be amplified many times in their propagation into the computed free energy [due to subtraction of similar numbers such as (105 ± 5)‒(100 ± 5) = 5 ± 7]. In this paper, we present an unsophisticated implementation of TI in 3n dimensions (3nD) (n=1,2,3…) for the potential of mean force along a 3nD path connecting one state in the bound state ensemble to one state in the unbound state ensemble. Fluctuations in these 3nD are integrated in the bound and unbound state ensembles but not along the 3nD path. Using TI3nD, we computed the standard binding free energies of three protein complexes: trometamol in Salmonella effector SpvD (n=1), biotin-avidin (n=2), and Colicin E9 endonuclease with cognate immunity protein Im9 (n=3). We employed three different protocols in three independent computations of E9-Im9 to show TI3nD's robustness. We also computed the hydration energies of ten biologically relevant compounds (n=1 for water, acetamide, urea, glycerol, trometamol, ammonium and n=2 for erythritol, 1,3-propanediol, xylitol, biotin). Each of the 15 computations is accomplishable within one (for hydration) to ten (for E9-Im9) days on an inexpensive GPU workstation. The computed results all agree with the available experimental data.
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Affiliation(s)
- Liao Y Chen
- Department of Physics, University of Texas at San Antonio, San Antonio, Texas 78249 U.S.A
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22
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Zhang L, Luan B, Zhou R. Parameterization of Molybdenum Disulfide Interacting with Water Using the Free Energy Perturbation Method. J Phys Chem B 2019; 123:7243-7252. [PMID: 31369702 DOI: 10.1021/acs.jpcb.9b02797] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Water contact angles (WCA) are often used to parametrize force field parameters of novel 2D nanomaterials, such as molybdenum disulfide (MoS2), which has emerged as a promising nanomaterial in many biomedical applications due to its unique and impressive properties. However, there is a wide range of water-MoS2 contact angles in the literature depending on the aging process on the surface of a MoS2 nanosheet and/or substrate material. In this study, we revisit and optimize existing parameters for the basal plane of MoS2 with two popular water models, TIP3P and SPC/E, using the wide range of WCAs from various experiments. We develop and deploy the free energy perturbation method for parametrizing MoS2 with experimentally determined WCAs for both fresh and aged surfaces. Energy decomposition analysis on the simulation trajectories reveals that MoS2-water interaction is dominated by van der Waals interaction, which mainly comes from the top layer of MoS2. We conclude that to describe both fresh and aged MoS2 surfaces it is convenient to only adjust the Lennard-Jones parameter εS (the depth of the potential well of a sulfur atom), which displays a surprisingly linear correlation with WCAs.
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Affiliation(s)
- Leili Zhang
- Computational Biology Center , IBM Thomas J. Watson Research Center , Yorktown Heights , New York 10598 , United States
| | - Binquan Luan
- Computational Biology Center , IBM Thomas J. Watson Research Center , Yorktown Heights , New York 10598 , United States
| | - Ruhong Zhou
- Computational Biology Center , IBM Thomas J. Watson Research Center , Yorktown Heights , New York 10598 , United States
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23
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Reinhardt CR, Hu QH, Bresnahan CG, Hati S, Bhattacharyya S. Cyclic Changes in Active Site Polarization and Dynamics Drive the 'Ping-pong' Kinetics in NRH:Quinone Oxidoreductase 2: An Insight from QM/MM Simulations. ACS Catal 2018; 8:12015-12029. [PMID: 31583178 DOI: 10.1021/acscatal.8b04193] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Quinone reductases belong to the family of flavin-dependent oxidoreductases. With the redox active cofactor, flavin adenine dinucleotide, quinone reductases are known to utilize a 'ping-pong' kinetic mechanism during catalysis in which a hydride is bounced back and forth between flavin and its two substrates. However, the continuation of this catalytic cycle requires product displacement steps, where the product of one redox half-cycle is displaced by the substrate of the next half-cycle. Using improved hybrid quantum mechanical/molecular mechanical simulations, both the catalytic hydride transfer and the product displacement reactions were studied in NRH:quinone oxidoreductase 2. Initially, the self-consistent charge-density functional tight binding theory was used to describe flavin ring and the substrate atoms, while embedded in the molecular mechanically-treated solvated active site. Then, for each step of the catalytic cycle, a further improvement of energetics was made using density functional theory-based corrections. The present study showcases an integrated interplay of solvation, protonation, and protein matrix-induced polarization as the driving force behind the thermodynamic wheel of the 'ping-pong' kinetics. Reported here is the first-principles model of the 'ping-pong' kinetics that portrays how cyclic changes in the active site polarization and dynamics govern the oscillatory hydride transfer and product displacement in this enzyme.
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Affiliation(s)
- Clorice R. Reinhardt
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Quin H. Hu
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Caitlin G. Bresnahan
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Sanchita Hati
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Sudeep Bhattacharyya
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
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24
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Bansal N, Zheng Z, Song LF, Pei J, Merz KM. The Role of the Active Site Flap in Streptavidin/Biotin Complex Formation. J Am Chem Soc 2018; 140:5434-5446. [PMID: 29607642 DOI: 10.1021/jacs.8b00743] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Obtaining a detailed description of how active site flap motion affects substrate or ligand binding will advance structure-based drug design (SBDD) efforts on systems including the kinases, HSP90, HIV protease, ureases, etc. Through this understanding, we will be able to design better inhibitors and better proteins that have desired functions. Herein we address this issue by generating the relevant configurational states of a protein flap on the molecular energy landscape using an approach we call MTFlex-b and then following this with a procedure to estimate the free energy associated with the motion of the flap region. To illustrate our overall workflow, we explored the free energy changes in the streptavidin/biotin system upon introducing conformational flexibility in loop3-4 in the biotin unbound ( apo) and bound ( holo) state. The free energy surfaces were created using the Movable Type free energy method, and for further validation, we compared them to potential of mean force (PMF) generated free energy surfaces using MD simulations employing the FF99SBILDN and FF14SB force fields. We also estimated the free energy thermodynamic cycle using an ensemble of closed-like and open-like end states for the ligand unbound and bound states and estimated the binding free energy to be approximately -16.2 kcal/mol (experimental -18.3 kcal/mol). The good agreement between MTFlex-b in combination with the MT method with experiment and MD simulations supports the effectiveness of our strategy in obtaining unique insights into the motions in proteins that can then be used in a range of biological and biomedical applications.
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Affiliation(s)
- Nupur Bansal
- Department of Chemistry and Department of Biochemistry and Molecular Biology , Michigan State University , 578 South Shaw Lane , East Lansing , Michigan 48824 , United States
| | - Zheng Zheng
- Department of Chemistry and Department of Biochemistry and Molecular Biology , Michigan State University , 578 South Shaw Lane , East Lansing , Michigan 48824 , United States
| | - Lin Frank Song
- Department of Chemistry and Department of Biochemistry and Molecular Biology , Michigan State University , 578 South Shaw Lane , East Lansing , Michigan 48824 , United States
| | - Jun Pei
- Department of Chemistry and Department of Biochemistry and Molecular Biology , Michigan State University , 578 South Shaw Lane , East Lansing , Michigan 48824 , United States
| | - Kenneth M Merz
- Department of Chemistry and Department of Biochemistry and Molecular Biology , Michigan State University , 578 South Shaw Lane , East Lansing , Michigan 48824 , United States.,Institute for Cyber Enabled Research , Michigan State University , 567 Wilson Road , East Lansing , Michigan 48824 , United States
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25
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El Hage K, Mondal P, Meuwly M. Free energy simulations for protein ligand binding and stability. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2017.1416115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Krystel El Hage
- Department of Chemistry, University of Basel , Basel, Switzerland
| | - Padmabati Mondal
- Department of Chemistry, University of Basel , Basel, Switzerland
| | - Markus Meuwly
- Department of Chemistry, University of Basel , Basel, Switzerland
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26
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Harger M, Li D, Wang Z, Dalby K, Lagardère L, Piquemal JP, Ponder J, Ren P. Tinker-OpenMM: Absolute and relative alchemical free energies using AMOEBA on GPUs. J Comput Chem 2017; 38:2047-2055. [PMID: 28600826 DOI: 10.1002/jcc.24853] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 05/06/2017] [Indexed: 12/27/2022]
Abstract
The capabilities of the polarizable force fields for alchemical free energy calculations have been limited by the high computational cost and complexity of the underlying potential energy functions. In this work, we present a GPU-based general alchemical free energy simulation platform for polarizable potential AMOEBA. Tinker-OpenMM, the OpenMM implementation of the AMOEBA simulation engine has been modified to enable both absolute and relative alchemical simulations on GPUs, which leads to a ∼200-fold improvement in simulation speed over a single CPU core. We show that free energy values calculated using this platform agree with the results of Tinker simulations for the hydration of organic compounds and binding of host-guest systems within the statistical errors. In addition to absolute binding, we designed a relative alchemical approach for computing relative binding affinities of ligands to the same host, where a special path was applied to avoid numerical instability due to polarization between the different ligands that bind to the same site. This scheme is general and does not require ligands to have similar scaffolds. We show that relative hydration and binding free energy calculated using this approach match those computed from the absolute free energy approach. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Matthew Harger
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, 78712
| | - Daniel Li
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, 78712
| | - Zhi Wang
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, 63130
| | - Kevin Dalby
- Division of Chemical Biology and Medicinal Chemistry, University of Texas at Austin, Austin, Texas, 78712
| | - Louis Lagardère
- Institut des Sciences du Calcul et des Données, UPMC Université Paris 06, F-75005, Paris, France
| | - Jean-Philip Piquemal
- Laboratoire de Chimie Théorique, Sorbonne Universités, UPMC, UMR7616 CNRS, Paris, France.,Institut Universitaire de France, Paris Cedex 05, 75231, France
| | - Jay Ponder
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, 63130
| | - Pengyu Ren
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, 78712
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27
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Ozawa M, Ozawa T, Nishio M, Ueda K. The role of CH/π interactions in the high affinity binding of streptavidin and biotin. J Mol Graph Model 2017; 75:117-124. [PMID: 28551501 DOI: 10.1016/j.jmgm.2017.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 04/27/2017] [Accepted: 05/02/2017] [Indexed: 11/28/2022]
Abstract
The streptavidin-biotin complex has an extraordinarily high affinity (Ka: 1015mol-1) and contains one of the strongest non-covalent interactions known. This strong interaction is widely used in biological tools, including for affinity tags, detection, and immobilization of proteins. Although hydrogen bond networks and hydrophobic interactions have been proposed to explain this high affinity, the reasons for it remain poorly understood. Inspired by the deceased affinity of biotin observed for point mutations of streptavidin at tryptophan residues, we hypothesized that a CH/π interaction may also contribute to the strong interaction between streptavidin and biotin. CH/π interactions were explored and analyzed at the biotin-binding site and at the interface of the subunits by the fragment molecular orbital method (FMO) and extended applications: PIEDA and FMO4. The results show that CH/π interactions are involved in the high affinity for biotin at the binding site of streptavidin. We further suggest that the involvement of CH/π interactions at the subunit interfaces and an extended CH/π network play more critical roles in determining the high affinity, rather than involvement at the binding site.
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Affiliation(s)
- Motoyasu Ozawa
- Central Research Laboratory, Kissei Pharmaceutical Co., Ltd., 4365-1 Hotakakashiwabara, Azumino, Nagano 399-8304, Japan.
| | - Tomonaga Ozawa
- Central Research Laboratory, Kissei Pharmaceutical Co., Ltd., 4365-1 Hotakakashiwabara, Azumino, Nagano 399-8304, Japan
| | | | - Kazuyoshi Ueda
- Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-Ku, Yokohama 240-8501, Japan
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Michel J, Foloppe N, Essex JW. Rigorous Free Energy Calculations in Structure-Based Drug Design. Mol Inform 2016; 29:570-8. [PMID: 27463452 DOI: 10.1002/minf.201000051] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 05/28/2010] [Indexed: 11/07/2022]
Abstract
Structure-based drug design could benefit greatly from computational methodologies that accurately predict the binding affinity of small compounds to target biomolecules. However, the current scoring functions used to rank compounds in virtual screens by docking are not sufficiently accurate to guide reliably the design of tight binding ligands. Thus, there is strong interest in methodologies based on molecular simulations of protein-ligand complexes which are perceived to be more accurate and, with advances in computing power, amenable to routine use. This report provides an overview of the technical details necessary to understand, execute and analyze binding free energy calculations, using free energy perturbation or thermodynamic integration methods. Examples of possible applications in structure-based drug design are discussed. Current methodological limitations are highlighted as well as a number of ongoing developments to improve the scope, reliability, and practicalities of free energy calculations. These efforts are paving the way for a more common use of free energy calculations in molecular design.
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Affiliation(s)
- Julien Michel
- Institute of Structural and Molecular Biology, The University of Edinburgh, Edinburgh, EH9 3JR, UK. .,Department of Chemistry, Yale University, New Haven, CT-06520, USA.
| | | | - Jonathan W Essex
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
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Insight on Mutation-Induced Resistance from Molecular Dynamics Simulations of the Native and Mutated CSF-1R and KIT. PLoS One 2016; 11:e0160165. [PMID: 27467080 PMCID: PMC4965071 DOI: 10.1371/journal.pone.0160165] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 07/14/2016] [Indexed: 01/22/2023] Open
Abstract
The receptors tyrosine kinases (RTKs) for the colony stimulating factor-1, CSF-1R, and for the stem cell factor, SCFR or KIT, are important mediators of signal transduction. The abnormal function of these receptors, promoted by gain-of-function mutations, leads to their constitutive activation, associated with cancer or other proliferative diseases. A secondary effect of the mutations is the alteration of receptors' sensitivity to tyrosine kinase inhibitors, compromising effectiveness of these molecules in clinical treatment. In particular, the mutation V560G in KIT increases its sensitivity to Imatinib, while the D816V in KIT, and D802V in CSF-1R, triggers resistance to the drug. We analyzed the Imatinib binding affinity to the native and mutated KIT (mutations V560G, S628N and D816V) and CSF-1R (mutation D802V) by using molecular dynamics simulations and energy calculations of Imatinib•target complexes. Further, we evaluated the sensitivity of the studied KIT receptors to Imatinib by measuring the inhibition of KIT phosphorylation. Our study showed that (i) the binding free energy of Imatinib to the targets is highly correlated with their experimentally measured sensitivity; (ii) the electrostatic interactions are a decisive factor affecting the binding energy; (iii) the most deleterious impact to the Imatinib sensitivity is promoted by D802V (CSF-1R) and D816V (KIT) mutations; (iv) the role of the juxtamembrane region, JMR, in the imatinib binding is accessory. These findings contribute to a better description of the mutation-induced effects alternating the targets sensitivity to Imatinib.
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Liu F, Zhang JZH, Mei Y. The origin of the cooperativity in the streptavidin-biotin system: A computational investigation through molecular dynamics simulations. Sci Rep 2016; 6:27190. [PMID: 27249234 PMCID: PMC4888747 DOI: 10.1038/srep27190] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 05/13/2016] [Indexed: 11/17/2022] Open
Abstract
Previous experimental study measuring the binding affinities of biotin to the wild type streptavidin (WT) and three mutants (S45A, D128A and S45A/D128A double mutant) has shown that the loss of binding affinity from the double mutation is larger than the direct sum of those from two single mutations. The origin of this cooperativity has been investigated in this work through molecular dynamics simulations and the end-state free energy method using the polarized protein-specific charge. The results show that this cooperativity comes from both the enthalpy and entropy contributions. The former contribution mainly comes from the alternations of solvation free energy. Decomposition analysis shows that the mutated residues nearly have no contributions to the cooperativity. Instead, N49 and S88, which are located at the entry of the binding pocket and interact with the carboxyl group of biotin, make the dominant contribution among all the residues in the first binding shell around biotin.
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Affiliation(s)
- Fengjiao Liu
- State Key Laboratory of Precision Spectroscopy, School of Physics and Materials Science, East China Normal University, Shanghai 200062, China
| | - John Z. H. Zhang
- Department of Physics, School of Physics and Materials Science, East China Normal University, Shanghai 200062, China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
| | - Ye Mei
- State Key Laboratory of Precision Spectroscopy, School of Physics and Materials Science, East China Normal University, Shanghai 200062, China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
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Katsila T, Spyroulias GA, Patrinos GP, Matsoukas MT. Computational approaches in target identification and drug discovery. Comput Struct Biotechnol J 2016; 14:177-84. [PMID: 27293534 PMCID: PMC4887558 DOI: 10.1016/j.csbj.2016.04.004] [Citation(s) in RCA: 185] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 04/21/2016] [Accepted: 04/25/2016] [Indexed: 12/31/2022] Open
Abstract
In the big data era, voluminous datasets are routinely acquired, stored and analyzed with the aim to inform biomedical discoveries and validate hypotheses. No doubt, data volume and diversity have dramatically increased by the advent of new technologies and open data initiatives. Big data are used across the whole drug discovery pipeline from target identification and mechanism of action to identification of novel leads and drug candidates. Such methods are depicted and discussed, with the aim to provide a general view of computational tools and databases available. We feel that big data leveraging needs to be cost-effective and focus on personalized medicine. For this, we propose the interplay of information technologies and (chemo)informatic tools on the basis of their synergy.
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Affiliation(s)
- Theodora Katsila
- University of Patras, School of Health Sciences, Department of Pharmacy, University Campus, Rion, Patras, Greece
| | - Georgios A. Spyroulias
- University of Patras, School of Health Sciences, Department of Pharmacy, University Campus, Rion, Patras, Greece
| | - George P. Patrinos
- University of Patras, School of Health Sciences, Department of Pharmacy, University Campus, Rion, Patras, Greece
- Department of Pathology, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Minos-Timotheos Matsoukas
- University of Patras, School of Health Sciences, Department of Pharmacy, University Campus, Rion, Patras, Greece
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Strzelczyk P, Bujacz G. Crystal structure and ligand affinity of avidin in the complex with 4′-hydroxyazobenzene-2-carboxylic acid. J Mol Struct 2016. [DOI: 10.1016/j.molstruc.2016.01.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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33
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Jeschek M, Panke S, Ward T. Periplasmic Screening for Artificial Metalloenzymes. Methods Enzymol 2016; 580:539-56. [DOI: 10.1016/bs.mie.2016.05.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Chang CE, Chen W, Gilson MK. Evaluating the Accuracy of the Quasiharmonic Approximation. J Chem Theory Comput 2015; 1:1017-28. [PMID: 26641917 DOI: 10.1021/ct0500904] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The quasiharmonic approximation (QH) allows the configurational entropy of a molecule to be estimated on the basis of a molecular dynamics simulation, through construction of a Gaussian probability distribution of conformations with variances equal to those provided by the simulation. At its introduction in 1981, the QH method was successfully applied to simple molecular systems with only one highly occupied energy well, and fluctuations were analyzed in a system of internal bond-angle-torsion coordinates. However, more recent studies have applied the QH method to complex biomolecular systems and have relied upon Cartesian coordinates. The present study evaluates the accuracy of the QH method through comparisons with more detailed methods. The chief findings are that the QH method can markedly overestimate the configurational entropy for systems with multiple occupied energy wells and that such errors tend to be magnified by the use of Cartesian coordinates instead of bond-angle-torsion coordinates.
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Affiliation(s)
- Chia-En Chang
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California, and Center for Advanced Research in Biotechnology, 9600 Gudelsky Drive, Rockville, Maryland 20850
| | - Wei Chen
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California, and Center for Advanced Research in Biotechnology, 9600 Gudelsky Drive, Rockville, Maryland 20850
| | - Michael K Gilson
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California, and Center for Advanced Research in Biotechnology, 9600 Gudelsky Drive, Rockville, Maryland 20850
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35
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Michel J, Verdonk ML, Essex JW. Protein-Ligand Complexes: Computation of the Relative Free Energy of Different Scaffolds and Binding Modes. J Chem Theory Comput 2015; 3:1645-55. [PMID: 26627610 DOI: 10.1021/ct700081t] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A methodology for the calculation of the free energy difference between a pair of molecules of arbitrary topology is proposed. The protocol relies on a dual-topology paradigm, a softening of the intermolecular interactions, and a constraint that prevents the perturbed molecules from drifting away from each other at the end states. The equivalence and the performance of the methodology against a single-topology approach are demonstrated on a pair of harmonic oscillators, the calculation of the relative solvation free energy of ethane and methanol, and the relative binding free energy of two congeneric inhibitors of cyclooxygenase 2. The stability of two alternative binding modes of an inhibitor of cyclin-dependent kinase 2 is then investigated. Finally, the relative binding free energy of two structurally different inhibitors of cyclin-dependent kinase 2 is calculated. The proposed methodology allows the study of a range of problems that are beyond the reach of traditional relative free energy calculation protocols and should prove useful in drug design studies.
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Affiliation(s)
- Julien Michel
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom, and Astex Therapeutics Ltd., 436 Cambridge Science Park, Cambridge, CB4 0QA, United Kingdom
| | - Marcel L Verdonk
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom, and Astex Therapeutics Ltd., 436 Cambridge Science Park, Cambridge, CB4 0QA, United Kingdom
| | - Jonathan W Essex
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom, and Astex Therapeutics Ltd., 436 Cambridge Science Park, Cambridge, CB4 0QA, United Kingdom
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36
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Abualrous ET, Saini SK, Ramnarayan VR, Ilca FT, Zacharias M, Springer S. The Carboxy Terminus of the Ligand Peptide Determines the Stability of the MHC Class I Molecule H-2Kb: A Combined Molecular Dynamics and Experimental Study. PLoS One 2015; 10:e0135421. [PMID: 26270965 PMCID: PMC4535769 DOI: 10.1371/journal.pone.0135421] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 07/21/2015] [Indexed: 11/18/2022] Open
Abstract
Major histocompatibility complex (MHC) class I molecules (proteins) bind peptides of eight to ten amino acids to present them at the cell surface to cytotoxic T cells. The class I binding groove binds the peptide via hydrogen bonds with the peptide termini and via diverse interactions with the anchor residue side chains of the peptide. To elucidate which of these interactions is most important for the thermodynamic and kinetic stability of the peptide-bound state, we have combined molecular dynamics simulations and experimental approaches in an investigation of the conformational dynamics and binding parameters of a murine class I molecule (H-2Kb) with optimal and truncated natural peptide epitopes. We show that the F pocket region dominates the conformational and thermodynamic properties of the binding groove, and that therefore the binding of the C terminus of the peptide to the F pocket region plays a crucial role in bringing about the peptide-bound state of MHC class I.
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Affiliation(s)
- Esam Tolba Abualrous
- Department of Chemistry and Life Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
- Department of Physics, Faculty of Science, Ain Shams University, Cairo, Egypt
| | - Sunil Kumar Saini
- Department of Chemistry and Life Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Venkat Raman Ramnarayan
- Department of Chemistry and Life Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Florin Tudor Ilca
- Department of Chemistry and Life Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Martin Zacharias
- Physik-Department T38, Technische Universität München, James-Franck-Strasse 1, 85748 Garching, Germany
| | - Sebastian Springer
- Department of Chemistry and Life Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
- * E-mail:
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Ferenczy GG. Computation of Drug-Binding Thermodynamics. THERMODYNAMICS AND KINETICS OF DRUG BINDING 2015. [DOI: 10.1002/9783527673025.ch3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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38
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Song J, Li Y, Ji C, Zhang JZH. Functional loop dynamics of the streptavidin-biotin complex. Sci Rep 2015; 5:7906. [PMID: 25601277 PMCID: PMC4298722 DOI: 10.1038/srep07906] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 12/19/2014] [Indexed: 11/09/2022] Open
Abstract
Accelerated molecular dynamics (aMD) simulation is employed to study the functional dynamics of the flexible loop(3-4) in the strong-binding streptavidin-biotin complex system. Conventional molecular (cMD) simulation is also performed for comparison. The present study reveals the following important properties of the loop dynamics: (1) The transition of loop(3-4) from open to closed state is observed in 200 ns aMD simulation. (2) In the absence of biotin binding, the open-state streptavidin is more stable, which is consistent with experimental evidences. The free energy (ΔG) difference is about 5 kcal/mol between two states. But with biotin binding, the closed state is more stable due to electrostatic and hydrophobic interactions between the loop(3-4) and biotin. (3) The closure of loop(3-4) is concerted to the stable binding of biotin to streptavidin. When the loop(3-4) is in its open-state, biotin moves out of the binding pocket, indicating that the interactions between the loop(3-4) and biotin are essential in trapping biotin in the binding pocket. (4) In the tetrameric streptavidin system, the conformational change of the loop(3-4) in each monomer is independent of each other. That is, there is no cooperative binding for biotin bound to the four subunits of the tetramer.
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Affiliation(s)
- Jianing Song
- State Key Laboratory of Precision Spectroscopy, Department of Physics, Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062, China
| | - Yongle Li
- Department of Chemistry, New York University
| | - Changge Ji
- 1] State Key Laboratory of Precision Spectroscopy, Department of Physics, Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062, China [2] Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai 200062, China [3] NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China 200062
| | - John Z H Zhang
- 1] State Key Laboratory of Precision Spectroscopy, Department of Physics, Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062, China [2] NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China 200062
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39
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Ji C, Mei Y. Some practical approaches to treating electrostatic polarization of proteins. Acc Chem Res 2014; 47:2795-803. [PMID: 24883956 DOI: 10.1021/ar500094n] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Conspectus Electrostatic interaction plays a significant role in determining many properties of biomolecules, which exist and function in aqueous solution, a highly polar environment. For example, proteins are composed of amino acids with charged, polar, and nonpolar side chains and their specific electrostatic properties are fundamental to the structure and function of proteins. An important issue that arises in computational study of biomolecular interaction and dynamics based on classical force field is lack of polarization. Polarization is a phenomenon in which the charge distribution of an isolated molecule will be distorted when interacting with another molecule or presented in an external electric field. The distortion of charge distribution is intended to lower the overall energy of the molecular system, which is counter balanced by the increased internal energy of individual molecules due to the distorted charge distributions. The amount of the charge redistribution, which characterizes the polarizability of a molecule, is determined by the level of the charge distortion. Polarization is inherently quantum mechanical, and therefore classical force fields with fixed atomic charges are incapable of capturing this important effect. As a result, simulation studies based on popular force fields, AMBER, CHARMM, etc., lack the polarization effect, which is a widely known deficiency in most computational studies of biomolecules today. Many efforts have been devoted to remedy this deficiency, such as adding additional movable charge on the atom, allowing atomic charges to fluctuate, or including induced multipoles. Although various successes have been achieved and progress at various levels has been reported over the past decades, the issue of lacking polarization in force field based simulations is far from over. For example, some of these methods do not always give converged results, and other methods require huge computational cost. This Account reviews recent work on developing polarized and polarizable force fields based on fragment quantum mechanical calculations for proteins. The methods described here are based on quantum mechanical calculations of proteins in solution, but with a different level of rigor and different computational efficiency for the molecular dynamics applications. In the general approach, a fragment quantum mechanical calculation for protein with implicit solvation is carried out to derive a polarized protein-specific charge (PPC) for any given protein structure. The PPC correctly reflects the polarization state of the protein in a given conformation, and it can also be dynamically changed as the protein changes conformation in dynamics simulations. Another approach that is computationally more efficient is the effective polarizable bond method in which only polar bonds or groups can be polarized and their polarizabilities are predetermined from quantum mechanical calculations of these groups in external electric fields. Both methods can be employed for applications in various situations by taking advantage of their unique features.
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Affiliation(s)
- Changge Ji
- State Key Laboratory of Precision Spectroscopy, Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062, China
- Institute for Advanced Interdisciplinary Research, East China Normal University, Shanghai 200062, China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
| | - Ye Mei
- State Key Laboratory of Precision Spectroscopy, Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062, China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
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Gadhe CG, Balupuri A, Kothandan G, Cho SJ. Theoretical Characterization of Binding Mode of Organosilicon Inhibitor with p38: Docking, MD Simulation and MM/GBSA Free Energy Approach. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.8.2494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Wang Y, Liu Y, Deberg HA, Nomura T, Hoffman MT, Rohde PR, Schulten K, Martinac B, Selvin PR. Single molecule FRET reveals pore size and opening mechanism of a mechano-sensitive ion channel. eLife 2014; 3:e01834. [PMID: 24550255 PMCID: PMC3925968 DOI: 10.7554/elife.01834] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The mechanosensitive channel of large conductance, which serves as a model system for mechanosensitive channels, has previously been crystallized in the closed form, but not in the open form. Ensemble measurements and electrophysiological sieving experiments show that the open-diameter of the channel pore is >25 Å, but the exact size and whether the conformational change follows a helix-tilt or barrel-stave model are unclear. Here we report measurements of the distance changes on liposome-reconstituted MscL transmembrane α-helices, using a ‘virtual sorting’ single-molecule fluorescence energy transfer. We observed directly that the channel opens via the helix-tilt model and the open pore reaches 2.8 nm in diameter. In addition, based on the measurements, we developed a molecular dynamics model of the channel structure in the open state which confirms our direct observations. DOI:http://dx.doi.org/10.7554/eLife.01834.001 Bacterial cells are full of fluid, and they will burst if they are not able to respond to a build up of pressure. Fortunately, the membrane of a bacterial cell contains channels that can detect the increased mechanical stress on the cell membrane and then open to relieve the pressure. In many bacterial cells, the last defence against the cell exploding is called the mechanosensitive channel of large conductance (MscL). This is made of five proteins, each of which consists of TM1 and TM2 helixes, which are responsible for opening and closing the channel. Two models have been proposed to explain how the channels are opened. In the barrel-stave model, the TM1 helix moves, while the TM2 helix remains stationary. This results in an open pore that is lined with TM1 and TM2 helixes in the same way that wooden staves line a barrel. In the helix-tilt model, both helixes tilt towards the membrane to open the channel. Wang et al. have now used a technique called single-molecule fluorescence resonance energy transfer (FRET) to explore the structure of the open channel in E. coli in order to determine which model is correct. In this technique an individual channel is labeled with two different fluorescent molecules. By illuminating the channel with light of a wavelength that excites the first fluorescent molecule, and measuring the strength of the fluorescence from the second molecule, it is possible to work out the distance between the two molecules. From this, the structure of the channel and how it opens and closes can be explored. Previous attempts to measure the diameters of open channels using fluorescence techniques have suffered from issues caused by the use of large numbers of fluorescent molecules. This has made it necessary to use computational modeling to extract the required data. By looking at a series of individual proteins, Wang et al. overcame these problems and found that the diameter of the fully open pore is 2.8 nm. The result provides strong support for the helix-tilt model. DOI:http://dx.doi.org/10.7554/eLife.01834.002
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Affiliation(s)
- Yong Wang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
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42
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Bartholow TG, Sanford BL, Cao B, Schmit HL, Johnson JM, Meitzner J, Bhattacharyya S, Musier-Forsyth K, Hati S. Strictly conserved lysine of prolyl-tRNA Synthetase editing domain facilitates binding and positioning of misacylated tRNA(Pro.). Biochemistry 2014; 53:1059-68. [PMID: 24450765 PMCID: PMC3986007 DOI: 10.1021/bi401279r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
To ensure high fidelity in translation, many aminoacyl-tRNA synthetases, enzymes responsible for attaching specific amino acids to cognate tRNAs, require proof-reading mechanisms. Most bacterial prolyl-tRNA synthetases (ProRSs) misactivate alanine and employ a post-transfer editing mechanism to hydrolyze Ala-tRNA(Pro). This reaction occurs in a second catalytic site (INS) that is distinct from the synthetic active site. The 2'-OH of misacylated tRNA(Pro) and several conserved residues in the Escherichia coli ProRS INS domain are directly involved in Ala-tRNA(Pro) deacylation. Although mutation of the strictly conserved lysine 279 (K279) results in nearly complete loss of post-transfer editing activity, this residue does not directly participate in Ala-tRNA(Pro) hydrolysis. We hypothesized that the role of K279 is to bind the phosphate backbone of the acceptor stem of misacylated tRNA(Pro) and position it in the editing active site. To test this hypothesis, we carried out pKa, charge neutralization, and free-energy of binding calculations. Site-directed mutagenesis and kinetic studies were performed to verify the computational results. The calculations revealed a considerably higher pKa of K279 compared to an isolated lysine and showed that the protonated state of K279 is stabilized by the neighboring acidic residue. However, substitution of this acidic residue with a positively charged residue leads to a significant increase in Ala-tRNA(Pro) hydrolysis, suggesting that enhancement in positive charge density in the vicinity of K279 favors tRNA binding. A charge-swapping experiment and free energy of binding calculations support the conclusion that the positive charge at position 279 is absolutely necessary for tRNA binding in the editing active site.
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Affiliation(s)
- Thomas G Bartholow
- Department of Chemistry, University of Wisconsin-Eau Claire , Eau Claire, Wisconsin, 54702, United States
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General IJ, Meirovitch H. Absolute Free Energy of Binding and Entropy of the FKBP12-FK506 Complex: Effects of the Force Field. J Chem Theory Comput 2013; 9:4609-19. [PMID: 26589173 DOI: 10.1021/ct400484u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hypothetical scanning molecular dynamics (HSMD) method combined with thermodynamic integration (HSMD-TI) has been extended recently for calculating ΔA(0)-the absolute free energy of binding of a ligand to a protein. With HSMD-TI, ΔA(0) is obtained in a new way as a sum of several components, among them is ΔSligand-the change in the conformational entropy as the ligand is transferred from the bulk solvent to the active site-this entropy is obtained by a specific reconstruction procedure. This unique aspect of HSMD (which is useful in rational drug design) is in particular important for treating large ligands, where ΔSligand might be significant. Technically, one should verify that the results for ΔSligand converge-a property that might become more difficult for large ligands; therefore, studying ligands of increasing size would define the range of applicability of HSMD-TI for binding. In this paper, we check the performance of HSMD-TI by applying it to the relatively large ligand FK506 (126 atoms) complexed with the protein FKBP12, where ΔA(0) = -12.8 kcal/mol is known experimentally as well as the crystal structure of the complex. This structure was initially equilibrated by carrying out a 100 ns molecular dynamics trajectory, where the system is modeled by the AMBER force field, TIP3P water, and Particle Mesh Ewald. HSMD-TI calculations were carried out in three conformational regions defined by the intervals [0.2,2], [2,5], and [5,100] ns along the trajectory, where local equilibration of the total energy has been observed; we obtained ΔA(0) = -13.6 ± 1.1, -16.6 ± 1.4, and -16.7 ± 1.4 kcal/mol, respectively indicating the following: (1) The second and third regions belong to the same conformational subspace of the complex, which is different from the [0.2,2] ns subspace. (2) The unsatisfactory result for ΔA(0) obtained in the well equilibrated (hence theoretically preferred) latter regions reflects the nonperfect modeling used, which however (3) has led to the experimental ΔA(0) in the [0.2,2] ns region close to the crystal structure. Keeping the complex near its crystal structure has been a successful approach in the literature. To check this avenue further, we applied harmonic restraints on backbone atoms and obtained unsatisfactory results for ΔA(0), suggesting that implementation of this approach is not straightforward. Converging results for ΔSligand were obtained in all regions, where the result ΔSligand([0.2,2]) = 7.1 ± 1.2 kcal/mol is less region dependent than ΔA(0) and is relatively large probably due to the large ligand.
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Affiliation(s)
- Ignacio J General
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , 3059 BST3, Pittsburgh, Pennsylvania 15260, United States
| | - Hagai Meirovitch
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine , 3059 BST3, Pittsburgh, Pennsylvania 15260, United States.,Department of Physics, Bar-Ilan University , Ramat Gan, 52900, Israel
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Zeng J, Jia X, Zhang JZH, Mei Y. The F130L mutation in streptavidin reduces its binding affinity to biotin through electronic polarization effect. J Comput Chem 2013; 34:2677-86. [PMID: 24000160 DOI: 10.1002/jcc.23421] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 07/30/2013] [Accepted: 08/04/2013] [Indexed: 11/06/2022]
Abstract
Recently, Baugh et al. discovered that a distal point mutation (F130L) in streptavidin causes no distinct variation to the structure of the binding pocket but a 1000-fold reduction in biotin binding affinity. In this work, we carry out molecular dynamics simulations and apply an end-state free energy method to calculate the binding free energies of biotin to wild type streptavidin and its F130L mutant. The absolute binding affinities based on AMBER charge are repulsive, and the mutation induced binding loss is underestimated. When using the polarized protein-specific charge, the absolute binding affinities are significantly enhanced. In particular, both the absolute and relative binding affinities are in line with the experimental measurements. Further investigation indicates that polarization effect is indispensable in both the generation of structural ensembles and the calculation of interaction energies. This work verifies Baugh's conjecture that electrostatic polarization effect plays an essential role in modulating the binding affinity of biotin to the streptavidin through F130L mutation.
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Affiliation(s)
- Juan Zeng
- State Key Laboratory of Precision Spectroscopy, Department of Physics and Institute of Theoretical and Computational Science, East China Normal University, Shanghai, 200062, China
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Rocklin GJ, Mobley DL, Dill KA. Separated topologies--a method for relative binding free energy calculations using orientational restraints. J Chem Phys 2013; 138:085104. [PMID: 23464180 DOI: 10.1063/1.4792251] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Orientational restraints can improve the efficiency of alchemical free energy calculations, but they are not typically applied in relative binding calculations, which compute the affinity difference been two ligands. Here, we describe a new "separated topologies" method, which computes relative binding free energies using orientational restraints and which has several advantages over existing methods. While standard approaches maintain the initial and final ligand in a shared orientation, the separated topologies approach allows the initial and final ligands to have distinct orientations. This avoids a slowly converging reorientation step in the calculation. The separated topologies approach can also be applied to determine the relative free energies of multiple orientations of the same ligand. We illustrate the approach by calculating the relative binding free energies of two compounds to an engineered site in Cytochrome C Peroxidase.
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Affiliation(s)
- Gabriel J Rocklin
- Department of Pharmaceutical Chemistry, University of California San Francisco, 1700 4th St., San Francisco, California 94143-2550, USA.
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46
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Saracino GAA, Gelain F. Modelling and analysis of early aggregation events of BMHP1-derived self-assembling peptides. J Biomol Struct Dyn 2013; 32:759-75. [PMID: 23730849 DOI: 10.1080/07391102.2013.790848] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Despite the increasing use and development of peptide-based scaffolds in different fields including that of regenerative medicine, the understanding of the factors governing the self-assembly process and the relationship between sequence and properties have not yet been fully understood. BMHP1-derived self-assembling peptides (SAPs) have been developed and characterized showing that biotinylation at the N-terminal cap corresponds to better performing assembly and scaffold biomechanics. In this study, the effects of biotinylation on the self-assembly dynamics of seven BMHP1-derived SAPs have been investigated by molecular dynamics simulations. We confirmed that these SAPs self-assemble into β-structures and that proline acts as a β-breaker of the assembled aggregates. In biotinylated peptides, the formation of ordered β-structured aggregates is triggered by both the establishment of a dense and dynamic H-bonds network and the formation of a 'hydrophobic wall' available to interact with other peptides. Such conditions result from the peculiar chemical composition of the biotinyl-cap, given by the synergic cooperation of the uracil function of the ureido ring with the high hydrophobic portion consisting of the thiophenyl ring and valeryl chain. The inbuilt propensity of biotinylated peptides towards the formation of ordered small aggregates makes them ideal precursors of higher hierarchically organized self-assembled nanostructures as experimentally observed.
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Affiliation(s)
- Gloria Anna Ada Saracino
- a Center of Nanomedicine and Tissue Engineering A. O. Ospedale Niguarda Ca' Granda , Milan , 20162 Italy
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47
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Strzelczyk P, Bujacz A, Plażuk D, Zakrzewski J, Bujacz G. Structural investigation of the interactions of biotinylruthenocene with avidin. Chem Biol Interact 2013; 204:6-12. [PMID: 23603015 DOI: 10.1016/j.cbi.2013.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 03/27/2013] [Accepted: 04/11/2013] [Indexed: 11/15/2022]
Abstract
The crystal structure of avidin, a protein from hen egg white, was determined in the form of a complex with biotinylruthenocene. This biotin-derived organometallic ligand is a potential anticancer agent for targeted therapy based upon avidin-biotin technology. Isothermal titration calorimetry experiments, involving avidin complexes with biotin (vitamin H or B7) derivatives, show differences in their affinity to the protein in comparison to its avidin-biotin complex, the strongest known biochemical interaction in Nature. The crystal structure of the first complex of avidin with biotinylruthenocene, determined at 2.5Å resolution (PDB: 4I60), shows unique interactions of the ruthenocene moiety with avidin. Biotin derivatives exhibit weaker affinity to avidin then biotin, which allows their wider use in biotechnology. The specific properties of biotinylruthenocene and the knowledge of its interactions with avidin may be useful in biochemical, medical, and nanotechnological applications.
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Affiliation(s)
- Paweł Strzelczyk
- Institute of Technical Biochemistry, Lodz University of Technology, 90-924 Lodz, Stefanowskiego 4/10, Poland
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48
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Bykhovski A, Zhang W, Jensen J, Woolard D. Analysis of Electronic Structure, Binding, and Vibrations in Biotin–Streptavidin Complexes Based on Density Functional Theory and Molecular Mechanics. J Phys Chem B 2012; 117:25-37. [DOI: 10.1021/jp3075833] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexei Bykhovski
- Department of Electrical & Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Weidong Zhang
- Department of Electrical & Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - James Jensen
- U.S. Army Edgewood Chemical Biological Center, Aberdeen Proving Ground,
Maryland 21010, United States
| | - Dwight Woolard
- Department of Electrical & Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
- U.S Army Research Office, Research Triangle Park, North Carolina 27709,
United States
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49
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Comer J, Ho A, Aksimentiev A. Toward detection of DNA-bound proteins using solid-state nanopores: insights from computer simulations. Electrophoresis 2012; 33:3466-79. [PMID: 23147918 PMCID: PMC3789251 DOI: 10.1002/elps.201200164] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 07/05/2012] [Accepted: 07/09/2012] [Indexed: 11/07/2022]
Abstract
Through all-atom molecular dynamics simulations, we explore the use of nanopores in thin synthetic membranes for detection and identification of DNA binding proteins. Reproducing the setup of a typical experiment, we simulate electric field driven transport of DNA-bound proteins through nanopores smaller in diameter than the proteins. As model systems, we use restriction enzymes EcoRI and BamHI specifically and nonspecifically bound to a fragment of dsDNA, and streptavidin and NeutrAvidin proteins bound to dsDNA and ssDNA via a biotin linker. Our simulations elucidate the molecular mechanics of nanopore-induced rupture of a protein-DNA complex, the effective force applied to the DNA-protein bond by the electrophoretic force in a nanopore, and the role of DNA-surface interactions in the rupture process. We evaluate the ability of the nanopore ionic current and the local electrostatic potential measured by an embedded electrode to report capture of DNA, capture of a DNA-bound protein, and rupture of the DNA-protein bond. We find that changes in the strain on dsDNA can reveal the rupture of a protein-DNA complex by altering both the nanopore ionic current and the potential of the embedded electrode. Based on the results of our simulations, we suggest a new method for detection of DNA binding proteins that utilizes peeling of a nicked double strand under the electrophoretic force in a nanopore.
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Affiliation(s)
- Jeffrey Comer
- Department of Physics and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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50
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Li L, Li Y, Zhang L, Hou T. Theoretical Studies on the Susceptibility of Oseltamivir against Variants of 2009 A/H1N1 Influenza Neuraminidase. J Chem Inf Model 2012; 52:2715-29. [DOI: 10.1021/ci300375k] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Lin Li
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Youyong Li
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Liling Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Tingjun Hou
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
- College of
Pharmaceutical Sciences,
Soochow University, Suzhou, Jiangsu 215123, China
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