1
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Del ng BM, Olson A, Laracuente XE, Foreman KW, Paige M, Kehn-Hall K, Lockhart C, Klimov DK. Binding of Venezuelan Equine Encephalitis Virus Inhibitors to Importin-α Receptors Explored with All-Atom Replica Exchange Molecular Dynamics. J Phys Chem B 2023; 127:3175-3186. [PMID: 37001021 PMCID: PMC10358320 DOI: 10.1021/acs.jpcb.3c00429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Although Venezuelan equine encephalitis virus (VEEV) is a life-threatening pathogen with a capacity for epidemic outbreaks, there are no FDA-approved VEEV antivirals for humans. VEEV cytotoxicity is partially attributed to the formation of a tetrameric complex between the VEEV capsid protein, the nuclear import proteins importin-α and importin-β, and the nuclear export protein CRM1, which together block trafficking through the nuclear pore complex. Experimental studies have identified small molecules from the CL6662 scaffold as potential inhibitors of the viral nuclear localization signal (NLS) sequence binding to importin-α. However, little is known about the molecular mechanism of CL6662 inhibition. To address this issue, we employed all-atom replica exchange molecular dynamics simulations to probe, in atomistic detail, the binding mechanism of CL6662 ligands to importin-α. Three ligands, including G281-1485 and two congeners with varying hydrophobicities, were considered. We investigated the distribution of ligand binding poses, their locations, and ligand specificities measured by the strength of binding interactions. We found that G281-1485 binds nonspecifically without forming well-defined binding poses throughout the NLS binding site. Binding of the less hydrophobic congener becomes strongly on-target with respect to the NLS binding site but remains nonspecific. However, a more hydrophobic congener is a strongly specific binder and the only ligand out of three to form a well-defined binding pose, while partially overlapping with the NLS binding site. On the basis of free energy estimates, we argue that all three ligands weakly compete with the viral NLS sequence for binding to importin-α in an apparent compromise to preserve host NLS binding. We further show that all-atom replica exchange binding simulations are a viable tool for studying ligands binding nonspecifically without forming well-defined binding poses.
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Affiliation(s)
- Bryan M. Del ng
- School of Systems Biology, George Mason University, Manassas, VA 20110, USA
| | - Audrey Olson
- School of Systems Biology, George Mason University, Manassas, VA 20110, USA
| | | | - Kenneth W. Foreman
- Department of Chemistry and Biochemistry, George Mason University, Manassas, VA 20110, USA
| | - Mikell Paige
- Department of Chemistry and Biochemistry, George Mason University, Manassas, VA 20110, USA
| | - Kylene Kehn-Hall
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Center for Emerging, Zoonotic, and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | | | - Dmitri K. Klimov
- School of Systems Biology, George Mason University, Manassas, VA 20110, USA
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2
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Jana AK, Lander CW, Chesney AD, Hansmann UHE. Effect of an Amyloidogenic SARS-COV-2 Protein Fragment on α-Synuclein Monomers and Fibrils. J Phys Chem B 2022; 126:3648-3658. [PMID: 35580331 DOI: 10.1021/acs.jpcb.2c01254] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Aggregates of α-synuclein are thought to be the disease-causing agent in Parkinson's disease. Various case studies have hinted at a correlation between COVID-19 and the onset of Parkinson's disease. For this reason, we use molecular dynamics simulations to study whether amyloidogenic regions in SARS-COV-2 proteins can initiate and modulate aggregation of α-synuclein. As an example, we choose the nine-residue fragment SFYVYSRVK (SK9), located on the C-terminal of the envelope protein of SARS-COV-2. We probe how the presence of SK9 affects the conformational ensemble of α-synuclein monomers and the stability of two resolved fibril polymorphs. We find that the viral protein fragment SK9 may alter α-synuclein amyloid formation by shifting the ensemble toward aggregation-prone and preferentially rod-like fibril seeding conformations. However, SK9 has only a small effect on the stability of pre-existing or newly formed fibrils. A potential mechanism and key residues for potential virus-induced amyloid formation are described.
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Affiliation(s)
- Asis K Jana
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Chance W Lander
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Andrew D Chesney
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Ulrich H E Hansmann
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
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3
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Chen Y, Wei G, Zhao J, Nussinov R, Ma B. Computational Investigation of Gantenerumab and Crenezumab Recognition of Aβ Fibrils in Alzheimer's Disease Brain Tissue. ACS Chem Neurosci 2020; 11:3233-3244. [PMID: 32991803 PMCID: PMC8921974 DOI: 10.1021/acschemneuro.0c00364] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most devastating neurodegenerative diseases without effective therapies. Immunotherapies using antibodies to lower assembled Aβ provide a promising approach and have been widely studied. Anti-amyloid antibodies are often selective to amyloid conformation, and the lack of amyloid-antibody structural information limits our understanding of these antibodies' conformation selection. Gantenerumab and crenezumab are two anti-Aβ antibodies that bind multiple forms of Aβ with different Aβ epitope preferences. Here, using molecular dynamic (MD) simulations, we study the binding of these two antibodies to the Aβ1-40 fibril, whose conformation is derived from an AD patient's brain tissue. We find that gantenerumab recognizes the Aβ1-11 monomer fragment only at slightly lower pH than the physiological environment where His6 of Aβ1-11 is protonated. Both gantenerumab and crenezumab bind with integrated Aβ fibril rather than binding to monomers within the fibril. Gantenerumab preferentially binds to the N-terminal region of the Aβ1-40 fibril, and the binding is driven by aromatic interactions. Crenezumab can recognize the N-terminal region, as well as the cross-section of the Aβ1-40 fibril, indicating its multiple binding modes in Aβ fibril recognition. These results demonstrate conformation-dependent interactions of antibody-amyloid recognition.
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Affiliation(s)
- Yujie Chen
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Sciences (MOE), Multiscale Research Institute of Complex Systems, Fudan University, Shanghai 200438, P. R. China
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Sciences (MOE), Multiscale Research Institute of Complex Systems, Fudan University, Shanghai 200438, P. R. China
| | - Jun Zhao
- Basic Science Program, Leidos Biomedical Research, Inc., Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, United States
- Engineering Research Center of Cell & Therapeutic Antibody (MOE), School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
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4
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González-Alemán R, Hernández-Castillo D, Caballero J, Montero-Cabrera LA. Quality Threshold Clustering of Molecular Dynamics: A Word of Caution. J Chem Inf Model 2019; 60:467-472. [PMID: 31532987 DOI: 10.1021/acs.jcim.9b00558] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Clustering Molecular Dynamics trajectories is a common analysis that allows grouping together similar conformations. Several algorithms have been designed and optimized to perform this routine task, and among them, Quality Threshold stands as a very attractive option. This algorithm guarantees that in retrieved clusters no pair of frames will have a similarity value greater than a specified threshold, and hence, a set of strongly correlated frames are obtained for each cluster. In this work, it is shown that various commonly used software implementations are flawed by confusing Quality Threshold with another simplistic well-known clustering algorithm published by Daura et al. (Daura, X.; van Gunsteren, W. F.; Jaun, B.; Mark, A. E.; Gademann, K.; Seebach, D. Peptide Folding: When Simulation Meets Experiment. Angew. Chemie Int. Ed. 1999, 38 (1/2), 236-240). Daura's algorithm does not impose any quality threshold for the frames contained in retrieved clusters, bringing unrelated structural configurations altogether. The advantages of using Quality Threshold whenever possible to explore Molecular Dynamic trajectories is exemplified. An in-house implementation of the original Quality Threshold algorithm has been developed in order to illustrate our comments, and its code is freely available for further use by the scientific community.
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Affiliation(s)
- Roy González-Alemán
- Laboratorio de Química Computacional y Teórica, Facultad de Química , Universidad de La Habana , 10400 La Habana , Cuba
| | - David Hernández-Castillo
- Laboratorio de Química Computacional y Teórica, Facultad de Química , Universidad de La Habana , 10400 La Habana , Cuba
| | - Julio Caballero
- Centro de Bioinformática y Simulación Molecular, Facultad de Ingeniería en Bioinformática , Universidad de Talca , 2 Norte 685, Casilla 721 , Talca , Chile
| | - Luis A Montero-Cabrera
- Laboratorio de Química Computacional y Teórica, Facultad de Química , Universidad de La Habana , 10400 La Habana , Cuba
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5
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McClure R, Redha R, Vinson P, Pham W. A Robust and Scalable High-Throughput Compatible Assay for Screening Amyloid-β-Binding Compounds. J Alzheimers Dis 2019; 70:187-197. [PMID: 31177230 PMCID: PMC6943818 DOI: 10.3233/jad-190316] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A robust fluorescent readout assay using topologically-sensitive dyes improves the screening of novel amyloid-binding molecules. One of the key components that make this assay more realistic is the use of endogenous amyloid obtained from 5XFAD mouse brains. The assay conditions were optimized for high throughput screening operation with Z-prime values >0.6. Using a combination of library of 3,500 compounds including known drugs, natural-derived molecules and random organic molecules, 8 unique molecules were identified as potential amyloid-binding agents.
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Affiliation(s)
- Richard McClure
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
| | - Rey Redha
- Vanderbilt High-Throughput Screening Facility, Nashville, TN, USA
| | - Paige Vinson
- Vanderbilt High-Throughput Screening Facility, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
| | - Wellington Pham
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Ingram Cancer Center, Nashville, TN, USA
- Vanderbilt Institute of Chemical Biology, Nashville, TN, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Nashville, TN, USA
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6
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Salveson PJ, Haerianardakani S, Thuy-Boun A, Yoo S, Kreutzer AG, Demeler B, Nowick JS. Repurposing Triphenylmethane Dyes to Bind to Trimers Derived from Aβ. J Am Chem Soc 2018; 140:11745-11754. [PMID: 30125493 DOI: 10.1021/jacs.8b06568] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Soluble oligomers of the β-amyloid peptide, Aβ, are associated with the progression of Alzheimer's disease. Although many small molecules bind to these assemblies, the details of how these molecules interact with Aβ oligomers remain unknown. This paper reports that crystal violet, and other C3 symmetric triphenylmethane dyes, bind to C3 symmetric trimers derived from Aβ17-36. Binding changes the color of the dyes from purple to blue, and causes them to fluoresce red when irradiated with green light. Job plot and analytical ultracentrifugation experiments reveal that two trimers complex with one dye molecule. Studies with several triphenylmethane dyes reveal that three N, N-dialkylamino substituents are required for complexation. Several mutant trimers, in which Phe19, Phe20, and Ile31 were mutated to cyclohexylalanine, valine, and cyclohexylglycine, were prepared to probe the triphenylmethane dye binding site. Size exclusion chromatography, SDS-PAGE, and X-ray crystallographic studies demonstrate that these mutations do not impact the structure or assembly of the triangular trimer. Fluorescence spectroscopy and analytical ultracentrifugation experiments reveal that the dye packs against an aromatic surface formed by the Phe20 side chains and is clasped by the Ile31 side chains. Docking and molecular modeling provide a working model of the complex in which the triphenylmethane dye is sandwiched between two triangular trimers. Collectively, these findings demonstrate that the X-ray crystallographic structures of triangular trimers derived from Aβ can be used to guide the discovery of ligands that bind to soluble oligomers derived from Aβ.
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Affiliation(s)
- Patrick J Salveson
- Department of Chemistry , University of California Irvine , Irvine , California 92697-2025 , United States
| | - Sepehr Haerianardakani
- Department of Chemistry , University of California Irvine , Irvine , California 92697-2025 , United States
| | - Alexander Thuy-Boun
- Department of Chemistry , University of California Irvine , Irvine , California 92697-2025 , United States
| | - Stan Yoo
- Department of Chemistry , University of California Irvine , Irvine , California 92697-2025 , United States
| | - Adam G Kreutzer
- Department of Chemistry , University of California Irvine , Irvine , California 92697-2025 , United States
| | - Borries Demeler
- Department of Biochemistry , University of Texas Health Science Center , San Antonio , Texas 78229-3900 , United States
| | - James S Nowick
- Department of Chemistry , University of California Irvine , Irvine , California 92697-2025 , United States
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7
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Dcruz MM, Mamidipalli SS, Thakurdesai A, Andrade C. Curcumin for Neuroprotection: Taking a Second Look at Results. Am J Geriatr Psychiatry 2018; 26:715. [PMID: 29680181 DOI: 10.1016/j.jagp.2018.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 03/20/2018] [Accepted: 03/20/2018] [Indexed: 10/17/2022]
Affiliation(s)
- Migita Michael Dcruz
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | | | - Abha Thakurdesai
- Department of Psychiatry, Lokmanya Tilak Municipal Medical College and General Hospital, Mumbai, Maharashtra, India
| | - Chittaranjan Andrade
- Department of Psychopharmacology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
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8
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Siddarth P, Barrio JR, Small GW. Response to Letter About Memory and Brain Effects of Curcumin. Am J Geriatr Psychiatry 2018; 26:716-717. [PMID: 29681520 DOI: 10.1016/j.jagp.2018.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 03/23/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Prabha Siddarth
- Department of Psychiatry and Biobehavioral Sciences, UCLA Longevity Center, Semel Institute for Neuroscience and Human Behavior, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA
| | - Jorge R Barrio
- Department of Psychiatry and Biobehavioral Sciences, UCLA Longevity Center, Semel Institute for Neuroscience and Human Behavior, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA
| | - Gary W Small
- Department of Psychiatry and Biobehavioral Sciences, UCLA Longevity Center, Semel Institute for Neuroscience and Human Behavior, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA
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9
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Lockhart C, Klimov DK. Cholesterol Changes the Mechanisms of Aβ Peptide Binding to the DMPC Bilayer. J Chem Inf Model 2017; 57:2554-2565. [PMID: 28910085 DOI: 10.1021/acs.jcim.7b00431] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using isobaric-isothermal all-atom replica-exchange molecular dynamics (REMD) simulations, we investigated the equilibrium binding of Aβ10-40 monomers to the zwitterionic dimyristoylphosphatidylcholine (DMPC) bilayer containing cholesterol. Our previous REMD simulations, which studied binding of the same peptide to the cholesterol-free DMPC bilayer, served as a control, against which we measured the impact of cholesterol. Our findings are as follows. First, addition of cholesterol to the DMPC bilayer partially expels the Aβ peptide from the hydrophobic core and promotes its binding to bilayer polar headgroups. Using thermodynamic and energetics analyses, we argued that Aβ partial expulsion is not related to cholesterol-induced changes in lateral pressure within the bilayer but is caused by binding energetics, which favors Aβ binding to the surface of the densely packed cholesterol-rich bilayer. Second, cholesterol has a protective effect on the DMPC bilayer structure against perturbations caused by Aβ binding. More specifically, cholesterol reduces bilayer thinning and overall depletion of bilayer density beneath the Aβ binding footprint. Third, we found that the Aβ peptide contains a single cholesterol binding site, which involves hydrophobic C-terminal amino acids (Ile31-Val36), Phe19, and Phe20 from the central hydrophobic cluster, and cationic Lys28 from the turn region. This binding site accounts for about 76% of all Aβ-cholesterol interactions. Because cholesterol binding site in the Aβ10-40 peptide does not contain the GXXXG motif featured in cholesterol interactions with the transmembrane domain C99 of the β-amyloid precursor protein, we argued that the binding mechanisms for Aβ and C99 are distinct reflecting their different conformations and positions in the lipid bilayer. Fourth, cholesterol sharply reduces the helical propensity in the bound Aβ peptide. As a result, cholesterol largely eliminates the emergence of helical structure observed upon Aβ transition from a water environment to the cholesterol-free DMPC bilayer. We explain this effect by the formation of hydrogen bonds between cholesterol and the Aβ backbone, which prevent helix formation. Taken together, we expect that our simulations will advance understanding of a molecular-level mechanism behind the role of cholesterol in Alzheimer's disease.
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Affiliation(s)
- Christopher Lockhart
- School of Systems Biology, George Mason University , Manassas, Virginia 20110, United States
| | - Dmitri K Klimov
- School of Systems Biology, George Mason University , Manassas, Virginia 20110, United States
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10
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He H, Xu J, Cheng DY, Fu L, Ge YS, Jiang FL, Liu Y. Identification of Binding Modes for Amino Naphthalene 2-Cyanoacrylate (ANCA) Probes to Amyloid Fibrils from Molecular Dynamics Simulations. J Phys Chem B 2017; 121:1211-1221. [DOI: 10.1021/acs.jpcb.6b10460] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Huan He
- State
Key Laboratory of Virology, College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (MOE),
College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Juan Xu
- State
Key Laboratory of Virology, College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (MOE),
College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Dan-Yang Cheng
- State
Key Laboratory of Virology, College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (MOE),
College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Li Fu
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (MOE),
College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Yu-Shu Ge
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (MOE),
College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Feng-Lei Jiang
- State
Key Laboratory of Virology, College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (MOE),
College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Yi Liu
- State
Key Laboratory of Virology, College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
- Key
Laboratory of Analytical Chemistry for Biology and Medicine (MOE),
College of Chemistry Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
- School
of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, P. R. China
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11
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Gong Y, Zhu Y, Zou Y, Ma B, Nussinov R, Zhang Q. Human Neuronal Calcium Sensor-1 Protein Avoids Histidine Residues To Decrease pH Sensitivity. J Phys Chem B 2017; 121:508-517. [PMID: 28030949 PMCID: PMC6413881 DOI: 10.1021/acs.jpcb.6b11094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
pH is highly regulated in mammalian central nervous systems. Neuronal calcium sensor-1 (NCS-1) can interact with numerous target proteins. Compared to that in the NCS-1 protein of Caenorhabditis elegans, evolution has avoided the placement of histidine residues at positions 102 and 83 in the NCS-1 protein of humans and Xenopus laevis, possibly to decrease the conformational sensitivity to pH gradients in synaptic processes. We used all-atom molecular dynamics simulations to investigate the effects of amino acid substitutions between species on human NCS-1 by substituting Arg102 and Ser83 for histidine at neutral (R102H and S83H) and acidic pHs (R102Hp and S83Hp). Our cumulative 5 μs simulations revealed that the R102H mutation slightly increases the structural flexibility of loop L2 and the R102Hp mutation decreases protein stability. Community network analysis illustrates that the R102H and S83H mutations weaken the interdomain and strengthen the intradomain communications. Secondary structure contents in the S83H and S83Hp mutants are similar to those in the wild type, whereas the global structural stabilities and salt-bridge probabilities decrease. This study highlights the conformational dynamics effects of the R102H and S83H mutations on the local structural flexibility and global stability of NCS-1, whereas protonated histidine decreases the stability of NCS-1. Thus, histidines at positions 102 and 83 may not be compatible with the function of NCS-1 whether in the neutral or protonated state.
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Affiliation(s)
- Yehong Gong
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai, 200438, China
| | - Yuzhen Zhu
- Shanghai Normal University Physical Education College, 100 Gui Lin Road, Shanghai, 200234, China
| | - Yu Zou
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai, 200438, China
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- Department of Human Genetics and Molecular Medicine, Sackler Inst. of Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Qingwen Zhang
- College of Physical Education and Training, Shanghai University of Sport, 399 Chang Hai Road, Shanghai, 200438, China
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12
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Bhavaraju M, Phillips M, Bowman D, Aceves-Hernandez JM, Hansmann UHE. Binding of ACE-inhibitors to in vitro and patient-derived amyloid-β fibril models. J Chem Phys 2016; 144:015101. [PMID: 26747819 DOI: 10.1063/1.4938261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Currently, no drugs exist that can prevent or reverse Alzheimer's disease, a neurodegenerative disease associated with the presence, in the brain, of plaques that are composed of β-amyloid (Aβ) peptides. Recent studies suggest that angiotensin-converting enzyme (ACE) inhibitors, a set of drugs used to treat hypertension, may inhibit amyloid formation in vitro. In the present study, we investigate through computer simulations the binding of ACE inhibitors to patient-derived Aβ fibrils and contrast it with that of ACE inhibitors binding to in vitro generated fibrils. The binding affinities of the ACE inhibitors are compared with that of Congo red, a dye that is used to identify amyloid structures and that is known to be a weak inhibitor of Aβ aggregation. We find that ACE inhibitors have a lower binding affinity to the patient-derived fibrils than to in vitro generated ones. For patient-derived fibrils, their binding affinities are even lower than that of Congo red. Our observations raise doubts on the hypothesis that these drugs inhibit fibril formation in Alzheimer patients by interacting directly with the amyloids.
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Affiliation(s)
- Manikanthan Bhavaraju
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Malachi Phillips
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Deborah Bowman
- Department of Biology, Langston University, Langston, Oklahoma 73050, USA
| | - Juan M Aceves-Hernandez
- Department of Chemistry, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autonoma de Mexico, Cuautitlán Izcalli, Estado de Mexico, 15740, Mexico
| | - Ulrich H E Hansmann
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
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13
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Murugan NA, Halldin C, Nordberg A, Långström B, Ågren H. The Culprit Is in the Cave: The Core Sites Explain the Binding Profiles of Amyloid-Specific Tracers. J Phys Chem Lett 2016; 7:3313-3321. [PMID: 27498616 DOI: 10.1021/acs.jpclett.6b01586] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The design of molecular probes and tracer molecules with specificity toward amyloid beta (Aβ) fibrils is of paramount importance for the selective diagnosis of Alzheimer's disease. This requires a detailed understanding of the binding sites in amyloid targets, their number, and their binding mechanism for various tracer molecules. We adopt an integrated approach including molecular docking, molecular dynamics, and generalized Born-based free energy calculations to investigate site-specific interactions of different amyloid binding molecules. Our study reproduces the experimental results on the relative binding affinity of the tracers and amyloid binders and explains the feature of "multiple binding sites" in amyloid targets as probed by competition binding experiments. A major outcome of this study is that it is the core sites of the Aβ fibrils that are responsible for the experimentally reported binding profiles of tracers in amyloid targets rather than the surface sites that received much focus in earlier investigations.
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Affiliation(s)
- N Arul Murugan
- Division of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology (KTH) , AlbaNova University Center, S-106 91 Stockholm, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience (CNS), Psykiatricentrum, Karolinska Universitetssjukhuset, Solna , 171 76 Stockholm, Sweden
| | - Agneta Nordberg
- Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Translational Alzheimer Neurobiology, Karolinska Institutet, Department of Geriatric Medicine, Karolinska University Hospital, Huddinge , 141 86 Stockholm, Sweden
| | - Bengt Långström
- Department of Chemistry - BMC, Physical Organic Chemistry, Uppsala University , 751 23 Uppsala, Sweden
| | - Hans Ågren
- Division of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology (KTH) , AlbaNova University Center, S-106 91 Stockholm, Sweden
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