1
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Mondal S, Ghanta KP, Bandyopadhyay S. Microscopic Understanding of the Conformational Stability of the Aggregated Nonamyloid β Components of α-Synuclein. J Chem Inf Model 2023; 63:1542-1555. [PMID: 36866721 DOI: 10.1021/acs.jcim.2c01540] [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: 03/04/2023]
Abstract
Self-association of α-synuclein peptides into oligomeric species and ordered amyloid fibrils is associated with Parkinson's disease, a progressive neurodegenerative disorder. In particular, the peptide domain formed between the residues Glu-61 (or E61) and Val-95 (or V95) of α-synuclein, typically termed the "nonamyloid β component" (NAC), is known to play critical roles in forming aggregated structures. In this work, we have employed molecular dynamics simulations to explore the conformational properties and relative stabilities of aggregated protofilaments of different orders, namely, tetramer (P(4)), hexamer (P(6)), octamer (P(8)), decamer (P(10)), dodecamer (P(12)), and tetradecamer (P(14)), formed by the NAC domains of α-synuclein. Besides, center-of-mass pulling and umbrella sampling simulation methods have also been employed to characterize the mechanistic pathway of peptide association/dissociation and the corresponding free energy profiles. Structural analysis showed that the disordered C-terminal loop and the central core regions of the peptide units lead to more flexible and distorted structures of the lower order protofilaments (P(4) and P(6)) as compared to the higher order ones. Interestingly, our calculation shows the presence of multiple distinctly populated conformational states for the lower order protofilament P(4), which may drive the oligomerization process along multiple pathways to form different polymorphic α-synuclein fibrillar structures. It is further observed that the nonpolar interaction between the peptides and the corresponding nonpolar solvation free energy play a dominant role in stabilizing the aggregated protofilaments. Importantly, our result showed that reduced cooperativity during the binding of a peptide unit beyond a critical size of the protofilament (P(12)) leads to less favorable binding free energy of a peptide.
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Affiliation(s)
- Souvik Mondal
- Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Krishna Prasad Ghanta
- Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Sanjoy Bandyopadhyay
- Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
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2
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Wickstrom L, Gallicchio E, Chen L, Kurtzman T, Deng N. Developing end-point methods for absolute binding free energy calculation using the Boltzmann-quasiharmonic model. Phys Chem Chem Phys 2022; 24:6037-6052. [PMID: 35212338 PMCID: PMC9044818 DOI: 10.1039/d1cp05075c] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding the physical forces underlying receptor-ligand binding requires robust methods for analyzing the binding thermodynamics. In end-point binding free energy methods the binding free energy is naturally decomposable into physically intuitive contributions such as the solvation free energy and configurational entropy that can provide insights. Here we present a new end-point method called EE-BQH (Effective Energy-Boltzmann-Quasiharmonic) which combines the Boltzmann-Quasiharmonic model for configurational entropy with different solvation free energy methods, such as the continuum solvent PBSA model and the integral equation-based 3D-RISM, to estimate the absolute binding free energy. We compare EE-BQH with other treatments of configurational entropy such as Quasiharmonic models in internal coordinates (QHIC) and in Cartesian coordinates (QHCC), and Normal Mode analysis (NMA), by testing them on the octa acids host-guest complexes from the SAMPL8 blind challenge. The accuracies in the calculated absolute binding free energies strongly depend on the configurational entropy and solvation free energy methods used. QHIC and BQH yield the best agreements with the established potential of mean force (PMF) estimates, with R2 of ∼0.7 and mean unsigned error of ∼1.7 kcal mol-1. These results from the end-point calculations are also in similar agreement with experiments. While 3D-RISM in combination with QHIC or BQH lead to reasonable correlations with the PMF results and experiments, the calculated absolute binding free energies are underestimated by ∼5 kcal mol-1. While the binding is accompanied by a significant reduction in the ligand translational/rotational entropy, the change in the torsional entropy in these host-guest systems is slightly positive. Compared with BQH, QHIC underestimates the reduction of configurational entropy because of the non-Gaussian probability distributions in the ligand rotation and a small number of torsions. The study highlights the crucial role of configurational entropy in determining binding and demonstrates the potential of using the new end-point method to provide insights in more complex protein-ligand systems.
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Affiliation(s)
- Lauren Wickstrom
- Borough of Manhattan Community College, The City University of New York, Department of Science, New York, New York, USA
| | - Emilio Gallicchio
- Department of Chemistry, Brooklyn College, The City University of New York, Brooklyn, New York, USA.,PhD Program in Chemistry, Graduate Center of the City University of New York, New York, USA.,PhD Program in Biochemistry, Graduate Center of the City University of New York, New York, USA
| | - Lieyang Chen
- PhD Program in Chemistry, Graduate Center of the City University of New York, New York, USA.,PhD Program in Biochemistry, Graduate Center of the City University of New York, New York, USA.,Department of Chemistry, Lehman College, The City University of New York, Bronx, New York, USA
| | - Tom Kurtzman
- PhD Program in Chemistry, Graduate Center of the City University of New York, New York, USA.,PhD Program in Biochemistry, Graduate Center of the City University of New York, New York, USA.,Department of Chemistry, Lehman College, The City University of New York, Bronx, New York, USA
| | - Nanjie Deng
- Department of Chemistry and Physical Sciences, Pace University, New York, New York, USA.
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3
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Identifying hydrophobic protein patches to inform protein interaction interfaces. Proc Natl Acad Sci U S A 2021; 118:2018234118. [PMID: 33526682 DOI: 10.1073/pnas.2018234118] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Interactions between proteins lie at the heart of numerous biological processes and are essential for the proper functioning of the cell. Although the importance of hydrophobic residues in driving protein interactions is universally accepted, a characterization of protein hydrophobicity, which informs its interactions, has remained elusive. The challenge lies in capturing the collective response of the protein hydration waters to the nanoscale chemical and topographical protein patterns, which determine protein hydrophobicity. To address this challenge, here, we employ specialized molecular simulations wherein water molecules are systematically displaced from the protein hydration shell; by identifying protein regions that relinquish their waters more readily than others, we are then able to uncover the most hydrophobic protein patches. Surprisingly, such patches contain a large fraction of polar/charged atoms and have chemical compositions that are similar to the more hydrophilic protein patches. Importantly, we also find a striking correspondence between the most hydrophobic protein patches and regions that mediate protein interactions. Our work thus establishes a computational framework for characterizing the emergent hydrophobicity of amphiphilic solutes, such as proteins, which display nanoscale heterogeneity, and for uncovering their interaction interfaces.
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4
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Deng N, Xia J, Wickstrom L, Lin C, Wang K, He P, Yin Y, Yang D. Ligand Selectivity in the Recognition of Protoberberine Alkaloids by Hybrid-2 Human Telomeric G-Quadruplex: Binding Free Energy Calculation, Fluorescence Binding, and NMR Experiments. Molecules 2019; 24:molecules24081574. [PMID: 31010072 PMCID: PMC6515380 DOI: 10.3390/molecules24081574] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/15/2019] [Accepted: 04/19/2019] [Indexed: 11/23/2022] Open
Abstract
The human telomeric G-quadruplex (G4) is an attractive target for developing anticancer drugs. Natural products protoberberine alkaloids are known to bind human telomeric G4 and inhibit telomerase. Among several structurally similar protoberberine alkaloids, epiberberine (EPI) shows the greatest specificity in recognizing the human telomeric G4 over duplex DNA and other G4s. Recently, NMR study revealed that EPI recognizes specifically the hybrid-2 form human telomeric G4 by inducing large rearrangements in the 5′-flanking segment and loop regions to form a highly extensive four-layered binding pocket. Using the NMR structure of the EPI-human telomeric G4 complex, here we perform molecular dynamics free energy calculations to elucidate the ligand selectivity in the recognition of protoberberines by the human telomeric G4. The MM-PB(GB)SA (molecular mechanics-Poisson Boltzmann/Generalized Born) Surface Area) binding free energies calculated using the Amber force fields bsc0 and OL15 correlate well with the NMR titration and binding affinity measurements, with both calculations correctly identifying the EPI as the strongest binder to the hybrid-2 telomeric G4 wtTel26. The results demonstrated that accounting for the conformational flexibility of the DNA-ligand complexes is crucially important for explaining the ligand selectivity of the human telomeric G4. While the MD-simulated (molecular dynamics) structures of the G-quadruplex-alkaloid complexes help rationalize why the EPI-G4 interactions are optimal compared with the other protoberberines, structural deviations from the NMR structure near the binding site are observed in the MD simulations. We have also performed binding free energy calculation using the more rigorous double decoupling method (DDM); however, the results correlate less well with the experimental trend, likely due to the difficulty of adequately sampling the very large conformational reorganization in the G4 induced by the protoberberine binding.
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Affiliation(s)
- Nanjie Deng
- Department of Chemistry and Physical Sciences, Pace University, New York, NY 10038, USA.
| | - Junchao Xia
- Department of Mathematics and Department of Research Computing, Princeton University, Princeton, NJ 08544, USA.
| | - Lauren Wickstrom
- Department of Science, Borough of Manhattan Community College, the City University of New York, New York, NY 10007, USA.
| | - Clement Lin
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA.
| | - Kaibo Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA.
| | - Peng He
- James Frank Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA.
| | - Yunting Yin
- Department of Chemistry and Physical Sciences, Pace University, New York, NY 10038, USA.
| | - Danzhou Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA.
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5
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Chen J, Duan L, Ji C, Zhang JZH. Computational Study of PCSK9-EGFA Complex with Effective Polarizable Bond Force Field. Front Mol Biosci 2018; 4:101. [PMID: 29379787 PMCID: PMC5775225 DOI: 10.3389/fmolb.2017.00101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/28/2017] [Indexed: 12/16/2022] Open
Abstract
Inhibiting of Proprotein Convertase Subtilisin/Kexin-type 9 (PCSK9) and Low Density Lipoprotein Receptor (LDLR) binding is an effective way for reducing Low Density Lipoprotein cholesterol (LDL-C). Understanding the interaction between PCSK9 and LDLR is useful for PCSK9 inhibitor design. In this work, MD simulations with the standard (non-polarizable) AMBER force field and effective polarizable bond (EPB) force field were performed for wild type and four mutants of PCSK9 and EGFA (Epidermal Growth Factor-like repeat A) domain of LDLR complexes. These four mutants are gain-of-function mutants. The analysis of hydrogen bond dynamics and the relative binding free energy indicates that EPB is more reliable in simulating protein dynamics and predicting relative binding affinity. Structures sampled from MD simulations with the standard AMBER force field deviate too far away from crystal structures. Many important interaction components between of PCSK9 and EGFA no longer exist in the simulation with the Amber force field. For comparison, simulation using EPB force field gives more stable structures as shown by hydrogen bond analysis and produced relative binding free energies that are consistent with experimental results. Our study suggests that inclusion of polarization effects in MD simulation is important for studying the protein-protein interaction.
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Affiliation(s)
- Jian Chen
- Shanghai Engineering Research Center for Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Lili Duan
- School of Physics and Electronics, Shandong Normal University, Jinan, China
| | - Changge Ji
- Shanghai Engineering Research Center for Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China
| | - John Z H Zhang
- Shanghai Engineering Research Center for Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China
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6
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Khatua P, Sinha SK, Bandyopadhyay S. Size-Dependent Conformational Features of Aβ17–42 Protofilaments from Molecular Simulation Studies. J Chem Inf Model 2017; 57:2378-2392. [DOI: 10.1021/acs.jcim.7b00407] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Prabir Khatua
- Molecular
Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Sudipta Kumar Sinha
- Department
of Chemistry, Indian Institute of Technology Ropar, Ropar 140001, India
| | - Sanjoy Bandyopadhyay
- Molecular
Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
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7
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8
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Deng N, Hoyte A, Mansour YE, Mohamed MS, Fuchs JR, Engelman AN, Kvaratskhelia M, Levy R. Allosteric HIV-1 integrase inhibitors promote aberrant protein multimerization by directly mediating inter-subunit interactions: Structural and thermodynamic modeling studies. Protein Sci 2016; 25:1911-1917. [PMID: 27503276 PMCID: PMC5079246 DOI: 10.1002/pro.2997] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 08/04/2016] [Indexed: 12/19/2022]
Abstract
Allosteric HIV-1 integrase (IN) inhibitors (ALLINIs) bind at the dimer interface of the IN catalytic core domain (CCD), and potently inhibit HIV-1 by promoting aberrant, higher-order IN multimerization. Little is known about the structural organization of the inhibitor-induced IN multimers and important questions regarding how ALLINIs promote aberrant IN multimerization remain to be answered. On the basis of physical chemistry principles and from our analysis of experimental information, we propose that inhibitor-induced multimerization is mediated by ALLINIs directly promoting inter-subunit interactions between the CCD dimer and a C-terminal domain (CTD) of another IN dimer. Guided by this hypothesis, we have built atomic models of inter-subunit interfaces in IN multimers by incorporating information from hydrogen-deuterium exchange (HDX) measurements to drive protein-protein docking. We have also developed a novel free energy simulation method to estimate the effects of ALLINI binding on the association of the CCD and CTD. Using this structural and thermodynamic modeling approach, we show that multimer inter-subunit interface models can account for several experimental observations about ALLINI-induced multimerization, including large differences in the potencies of various ALLINIs, the mechanisms of resistance mutations, and the crucial role of solvent exposed R-groups in the high potency of certain ALLINIs. Our study predicts that CTD residues Tyr226, Trp235 and Lys266 are involved in the aberrant multimer interfaces. The key finding of the study is that it suggests the possibility of ALLINIs facilitating inter-subunit interactions between an external CTD and the CCD-CCD dimer interface.
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Affiliation(s)
- Nanjie Deng
- Center for Biophysics & Computational Biology/ICMS, Department of Chemistry, Temple University, Philadelphia, Pennsylvania, 19122.
| | - Ashley Hoyte
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, Ohio, 43210
| | - Yara E Mansour
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, 43210
- Faculty of Pharmacy, Pharmaceutical Organic Chemistry Department, Helwan University, Cairo, Egypt
| | - Mosaad S Mohamed
- Faculty of Pharmacy, Pharmaceutical Organic Chemistry Department, Helwan University, Cairo, Egypt
| | - James R Fuchs
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, 43210
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts, 02215
| | - Mamuka Kvaratskhelia
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, Ohio, 43210
| | - Ronald Levy
- Center for Biophysics & Computational Biology/ICMS, Department of Chemistry, Temple University, Philadelphia, Pennsylvania, 19122
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9
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Wang X, Sun X, Kuang G, Ågren H, Tu Y. A theoretical study on the molecular determinants of the affibody protein Z(Aβ3) bound to an amyloid β peptide. Phys Chem Chem Phys 2016; 17:16886-93. [PMID: 26060853 DOI: 10.1039/c5cp00615e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Amyloid beta (Aβ) peptides are small cleavage products of the amyloid precursor protein. Aggregates of Aβ peptides are thought to be linked with Alzheimer's and other neurodegenerative diseases. Strategies aimed at inhibiting amyloid formation and promoting Aβ clearance have been proposed and investigated in in vitro experiments and in vivo therapies. A recent study indicated that a novel affibody protein ZAβ3, which binds to an Aβ40 monomer with a binding affinity of 17 nM, is able to prevent the aggregation of Aβ40. However, little is known about the energetic contribution of each residue in ZAβ3 to the formation of the (ZAβ3)2:Aβ complex. To address this issue, we carried out unbiased molecular dynamics simulations and molecular mechanics Poisson-Boltzmann surface area calculations. Through the per-residue decomposition scheme, we identified that the van der Waals interactions between the hydrophobic residues of (ZAβ3)2 and those at the exterior and interior faces of Aβ are the main contributors to the binding of (ZAβ3)2 to Aβ. Computational alanine scanning identified 5 hot spots, all residing in the binding interface and contributing to the binding of (ZAβ3)2 to Aβ through the hydrophobic effect. In addition, the amide hydrogen bonds in the 4-strand β-sheet and the π-π stacking were also analyzed. Overall, our study provides a theoretical basis for future experimental improvement of the ZAβ3 peptide binding to Aβ.
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Affiliation(s)
- Xu Wang
- Division of Theoretical Chemistry and Biology, School of Biotechnology, KTH Royal Institute of Technology, S-106 91 Stockholm, Sweden.
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10
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Understanding the effects on constitutive activation and drug binding of a D130N mutation in the β2 adrenergic receptor via molecular dynamics simulation. J Mol Model 2014; 20:2491. [PMID: 25342155 DOI: 10.1007/s00894-014-2491-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/06/2014] [Indexed: 01/21/2023]
Abstract
G-protein-coupled receptors (GPCRs) are currently one of the largest families of drug targets. The constitutive activation induced by mutation of key GPCR residues is associated closely with various diseases. However, the structural basis underlying such activation and its role in drug binding has remained unclear. Herein, we used all-atom molecular dynamics simulations and free energy calculations to study the effects of a D130N mutation on the structure of β2 adrenergic receptor (β2AR) and its binding of the agonist salbutamol. The results indicate that the mutation caused significant changes in some key helices. In particular, the mutation leads to the departure of transmembrane 3 (TM3) from transmembrane 6 (TM6) and marked changes in the NPxxY region as well as the complete disruption of a key ionic lock, all of which contribute to the observed constitutive activation. In addition, the D130N mutation weakens some important H-bonds, leading to structural changes in these regions. Binding free energy calculations indicate that van der Waals and electrostatic interactions are the main driving forces in binding salbutamol; however, binding strength in the mutant β2AR is significantly enhanced mainly through modifying electrostatic interactions. Further analysis revealed that the increase in binding energy upon mutation stems mainly from the H-bonds formed between the hydroxyl group of salbutamol and the serine residues of TM5. This observation suggests that modifications of the H-bond groups of this drug could significantly influence drug efficacy in the treatment of diseases associated with this mutation.
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11
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Meng Y, Yuan Y, Zhu Y, Guo Y, Li M, Wang Z, Pu X, Jiang L. Effects of organic solvents and substrate binding on trypsin in acetonitrile and hexane media. J Mol Model 2013; 19:3749-66. [DOI: 10.1007/s00894-013-1900-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/27/2013] [Indexed: 11/29/2022]
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12
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Liu FF, Liu Z, Bai S, Dong XY, Sun Y. Exploring the inter-molecular interactions in amyloid-β protofibril with molecular dynamics simulations and molecular mechanics Poisson-Boltzmann surface area free energy calculations. J Chem Phys 2012; 136:145101. [PMID: 22502547 DOI: 10.1063/1.3702195] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Aggregation of amyloid-β (Aβ) peptides correlates with the pathology of Alzheimer's disease. However, the inter-molecular interactions between Aβ protofibril remain elusive. Herein, molecular mechanics Poisson-Boltzmann surface area analysis based on all-atom molecular dynamics simulations was performed to study the inter-molecular interactions in Aβ(17-42) protofibril. It is found that the nonpolar interactions are the important forces to stabilize the Aβ(17-42) protofibril, while electrostatic interactions play a minor role. Through free energy decomposition, 18 residues of the Aβ(17-42) are identified to provide interaction energy lower than -2.5 kcal/mol. The nonpolar interactions are mainly provided by the main chain of the peptide and the side chains of nine hydrophobic residues (Leu17, Phe19, Phe20, Leu32, Leu34, Met35, Val36, Val40, and Ile41). However, the electrostatic interactions are mainly supplied by the main chains of six hydrophobic residues (Phe19, Phe20, Val24, Met35, Val36, and Val40) and the side chains of the charged residues (Glu22, Asp23, and Lys28). In the electrostatic interactions, the overwhelming majority of hydrogen bonds involve the main chains of Aβ as well as the guanidinium group of the charged side chain of Lys28. The work has thus elucidated the molecular mechanism of the inter-molecular interactions between Aβ monomers in Aβ(17-42) protofibril, and the findings are considered critical for exploring effective agents for the inhibition of Aβ aggregation.
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Affiliation(s)
- Fu-Feng Liu
- Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
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13
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Zhang H, Yao Y, Yang H, Wang X, Kang Z, Li Y, Li G, Wang Y. Molecular dynamics and free energy studies on the carboxypeptidases complexed with peptide/small molecular inhibitor: mechanism for drug resistance. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 42:583-595. [PMID: 22549081 DOI: 10.1016/j.ibmb.2012.04.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 05/31/2023]
Abstract
As one potent plant protease inhibitor, potato carboxypeptidase inhibitor (PCI) can competitively inhibit insect digestive metallocarboxypeptidases (MCPs) through interfering with its digestive system that causes amino acid deficiencies and leading to serious developmental delay and mortality. However, this effective biological pest control is significantly impaired by the PCI-resistant insect MCPs. Therefore, deep understanding of the resistant mechanism of insect MCPs is particularly necessary for designing new durable pest control regimen and developing effective pesticides. In this study, the binding of PCI and small molecular inhibitor THI to insect PCI-sensitive/-resistant MCPs and human MCP was investigated by docking, molecular dynamics (MD) simulations and thermodynamic analysis. The structural analysis from MD simulations indicates that the PCI-resistant mechanism of CPBHz is mainly dominated by the Trp277A, which changes the conformation of β8-α9 loop and therefore narrow the access to the active site of CPBHz, prohibiting the entrance of the C termini tail of PCI. Additionally, the insertion of Gly247A weakens the stabilization of CPBHz and PCI through disrupting the hydrogen bond formation with its surrounding residues. Furthermore, the predicted binding free energies gives explanation of structure affinity relationship of PCI and THI with MCPs and suggest that the electrostatic energy is the main contribution term affecting the difference in binding affinities. Finally, the decomposition analysis of binding free energies infers that the key residues Glu72, Arg127, Ile247/Leu247 and Glu270 are critical for the binding of PCI/THI to MCPs.
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Affiliation(s)
- Hong Zhang
- Bioinformatics Center, College of Life Sciences, State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Shaanxi 712100, China
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14
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Guo J, Wang X, Sun H, Liu H, Shen Y, Yao X. The Evolution of HLA-B*3501 Binding Affinity to Variable Immunodominant NP418-426 Peptides from 1918 to 2009 Pandemic Influenza A Virus: A Molecular Dynamics Simulation and Free Energy Calculation Study. Chem Biol Drug Des 2012; 79:1025-32. [DOI: 10.1111/j.1747-0285.2012.01357.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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15
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Deng NJ, Zhang P, Cieplak P, Lai L. Elucidating the energetics of entropically driven protein-ligand association: calculations of absolute binding free energy and entropy. J Phys Chem B 2011; 115:11902-10. [PMID: 21899337 DOI: 10.1021/jp204047b] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The binding of proteins and ligands is generally associated with the loss of translational, rotational, and conformational entropy. In many cases, however, the net entropy change due to binding is positive. To develop a deeper understanding of the energetics of entropically driven protein-ligand binding, we calculated the absolute binding free energies and binding entropies for two HIV-1 protease inhibitors Nelfinavir and Amprenavir using the double-decoupling method with molecular dynamics simulations in explicit solvent. For both ligands, the calculated absolute binding free energies are in general agreement with experiments. The statistical error in the computed ΔG(bind) due to convergence problem is estimated to be ≥2 kcal/mol. The decomposition of free energies indicates that, although the binding of Nelfinavir is driven by nonpolar interaction, Amprenavir binding benefits from both nonpolar and electrostatic interactions. The calculated absolute binding entropies show that (1) Nelfinavir binding is driven by large entropy change and (2) the entropy of Amprenavir binding is much less favorable compared with that of Nelfinavir. Both results are consistent with experiments. To obtain qualitative insights into the entropic effects, we decomposed the absolute binding entropy into different contributions based on the temperature dependence of free energies along different legs of the thermodynamic pathway. The results suggest that the favorable entropic contribution to binding is dominated by the ligand desolvation entropy. The entropy gain due to solvent release from binding site appears to be more than offset by the reduction of rotational and vibrational entropies upon binding.
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Affiliation(s)
- Nan-jie Deng
- BioMaPS Institute for Quantitative Biology and Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States.
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16
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Liu FF, Dong XY, He L, Middelberg APJ, Sun Y. Molecular insight into conformational transition of amyloid β-peptide 42 inhibited by (-)-epigallocatechin-3-gallate probed by molecular simulations. J Phys Chem B 2011; 115:11879-87. [PMID: 21899367 DOI: 10.1021/jp202640b] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Considerable experimental evidence indicates that (-)-epigallocatechin-3-gallate (EGCG) inhibits the fibrillogenesis of Aβ(42) and alleviates its associated cytotoxicity. However, the molecular mechanism of the inhibition effect of EGCG on the conformational transition of Aβ(42) remains unclear due to the limitations of current experimental techniques. In this work, molecular dynamics simulations and molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) analysis were coupled to better understand the issue. It was found that the direct interactions between EGCG and the peptide are the origin of its inhibition effects. Specifically, EGCG molecules expel water from the surface of the Aβ(42), cluster with each other, and interact directly with the peptide. The results of free energy decomposition calculated by MM-PBSA indicate that the nonpolar term contributes more than 71% to the binding free energy of the EGCG-Aβ(42) complex, while polar interactions (i.e., hydrogen bonding) play a minor role. It was identified that there are 12 important residues of Aβ(42) that strongly interact with EGCG (Phe4, Arg5, Phe19, Phe20, Glu22, Lys28, Gly29, Leu34-Gly37, and Ile41), while nonpolar interactions are mainly provided by the side chains of some hydrophobic residues (Phe, Met and Ile) and the main chains of some nonhydrophobic residues (Lys28 and Gly29). On the contrary, polar interactions are mainly formed by the main chain of Aβ(42), of which the main chains of Gly29 and Gly37 contribute greatly. The work has thus elucidated the molecular mechanism of the inhibition effect of EGCG on the conformational transition of Aβ(42), and the findings are considered critical for exploring more effective agents for the inhibition of Aβ(42) fibrillogenesis.
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Affiliation(s)
- Fu-Feng Liu
- Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
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The molecular basis of IGF-II/IGF2R recognition: a combined molecular dynamics simulation, free-energy calculation and computational alanine scanning study. J Mol Model 2011; 18:1421-30. [DOI: 10.1007/s00894-011-1159-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 06/21/2011] [Indexed: 01/05/2023]
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