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de Bruyn E, Dorn AE, Rossetti G, Fernandez C, Outeiro TF, Schulz JB, Carloni P. Impact of Phosphorylation on the Physiological Form of Human alpha-Synuclein in Aqueous Solution. J Chem Inf Model 2024; 64:8215-8226. [PMID: 39462994 DOI: 10.1021/acs.jcim.4c01172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2024]
Abstract
Serine 129 can be phosphorylated in pathological inclusions formed by the intrinsically disordered protein human α-synuclein (AS), a key player in Parkinson's disease and other synucleinopathies. Here, molecular simulations provide insight into the structural ensemble of phosphorylated AS. The simulations allow us to suggest that phosphorylation significantly impacts the structural content of the physiological AS conformational ensemble in aqueous solution, as the phosphate group is mostly solvated. The hydrophobic region of AS contains β-hairpin structures, which may increase the propensity of the protein to undergo amyloid formation, as seen in the nonphysiological (nonacetylated) form of the protein in a recent molecular simulation study. Our findings are consistent with existing experimental data with the caveat of the observed limitations of the force field for the phosphorylated moiety.
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Affiliation(s)
- Emile de Bruyn
- Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, 52062 Aachen, Germany
| | - Anton Emil Dorn
- Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Faculty of Biology, University of Duisburg-Essen, 45141 Essen, Germany
| | - Giulia Rossetti
- Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Computational Biomedicine (IAS-5/INM-9), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Department of Neurology, RWTH Aachen University, 52074 Aachen, Germany
| | - Claudio Fernandez
- Max Planck Laboratory for Structural Biology, Chemistry and Molecular Biophysics of Rosario (MPLbioR, UNR-MPINAT), Partner of the Max Planck Institute for Multidisciplinary Sciences (MPINAT, MPG), Centro de Estudios Interdisciplinarios, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
- Max Planck Institute for Multidisciplinary Sciences, 37075 Göttingen, Germany
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Jörg B Schulz
- Department of Physics, RWTH Aachen University, 52062 Aachen, Germany
- Department of Neurology, RWTH Aachen University, 52074 Aachen, Germany
- JARA Brain Institute Molecular Neuroscience and Neuroimaging (INM-11), Research Centre Jülich and RWTH Aachen University, 52074 Aachen, Germany
| | - Paolo Carloni
- Department of Physics, RWTH Aachen University, 52062 Aachen, Germany
- Computational Biomedicine (IAS-5/INM-9), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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2
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Vollmers L, Zacharias M. Advanced sampling simulations of coupled folding and binding of phage P22 N-peptide to boxB RNA. Biophys J 2024; 123:3463-3477. [PMID: 39210596 PMCID: PMC11480772 DOI: 10.1016/j.bpj.2024.08.022] [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: 05/18/2024] [Revised: 07/08/2024] [Accepted: 08/26/2024] [Indexed: 09/04/2024] Open
Abstract
Protein-RNA interactions are crucially important for numerous cellular processes and often involve coupled folding and binding of peptide segments upon association. The Nut-utilization site (N)-protein of bacteriophages contains an N-terminal arginine-rich motif that undergoes such a folding transition upon binding to the boxB RNA hairpin loop target structure. Molecular dynamics free energy simulations were used to calculate the absolute binding free energy of the N-peptide of bacteriophage P22 in complex with the boxB RNA hairpin motif at different salt concentrations and using two different water force field models. We obtained good agreement with experiment also at different salt concentrations for the TIP4P-D water model that has a stabilizing effect on unfolded protein structures. It allowed us to estimate the free energy contribution resulting from restricting the molecules' spatial and conformational freedom upon binding, which makes a large opposing contribution to binding. In a second set of umbrella sampling simulations to dissociate/associate the complex along a separation coordinate, we analyzed the onset of preorientation of the N-peptide and onset of structure formation relative to the RNA and its dependence on the salt concentration. Peptide orientation and conformational transitions are significantly coupled to the first contact formation between peptide and RNA. The initial contacts are mostly formed between peptide residues and the boxB hairpin loop nucleotides. A complete transition to an α-helical bound peptide conformation occurs only at a late stage of the binding process a few angstroms before the complexed state has been reached. However, the N-peptide orients also at distances beyond the contact distance such that the sizable positive charge points toward the RNA's center-of-mass. Our result may have important implications for understanding protein- and peptide-RNA complex formation frequently involving coupled folding and association processes.
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Affiliation(s)
- Luis Vollmers
- Physics Department and Center of Protein Assemblies, Technical University Munich, Garching, Germany
| | - Martin Zacharias
- Physics Department and Center of Protein Assemblies, Technical University Munich, Garching, Germany.
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3
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Hu G, Song H, Chen X, Li J. Wet Conformation of Prion-Like Domain and Intimate Correlation of Hydration and Conformational Fluctuations. J Phys Chem Lett 2024; 15:8315-8325. [PMID: 39109535 DOI: 10.1021/acs.jpclett.4c01476] [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: 08/16/2024]
Abstract
Proteins with prion-like domains (PLDs) are involved in neurodegeneration-associated aggregation and are prevalent in liquid-like membrane-less organelles. These PLDs contain amyloidogenic stretches but can maintain dynamic disordered conformations, even in the condensed phase. However, the molecular mechanism underlying such intricate conformational properties of PLDs remains elusive. Here we employed molecular dynamics simulations to investigate the conformational properties of a prototypical PLD system (i.e., FUS PLD). According to our simulation results, PLD adopts a wet collapsed conformation, wherein most residues maintain sufficient hydration with the abundance of internal water. These internal water molecules can rapidly exchange between the protein interior and the bulk, enabling intensive coupling of the entire protein with its hydration environment. The dynamic exchange of water molecules is intimately correlated to the overall conformational fluctuations of PLD. Furthermore, the abundance of dynamic internal water suppresses the formation of aggregation-prone ordered structures. These results collectively elucidate the crucial role of internal water in sustaining the dynamic disordered conformation of the PLD and inhibiting its aggregation propensity.
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Affiliation(s)
- Guorong Hu
- School of Physics, Zhejiang University, Hangzhou 310058, China
| | - Haoyu Song
- School of Physics, Zhejiang University, Hangzhou 310058, China
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Jingyuan Li
- School of Physics, Zhejiang University, Hangzhou 310058, China
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4
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Martins G, Galamba N. Wild-Type α-Synuclein Structure and Aggregation: A Comprehensive Coarse-Grained and All-Atom Molecular Dynamics Study. J Chem Inf Model 2024; 64:6115-6131. [PMID: 39046235 PMCID: PMC11323248 DOI: 10.1021/acs.jcim.4c00965] [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] [Received: 06/05/2024] [Revised: 07/14/2024] [Accepted: 07/18/2024] [Indexed: 07/25/2024]
Abstract
α-Synuclein (α-syn) is a 140 amino acid intrinsically disordered protein (IDP) and the primary component of cytotoxic oligomers implicated in the etiology of Parkinson's disease (PD). While IDPs lack a stable three-dimensional structure, they sample a heterogeneous ensemble of conformations that can, in principle, be assessed through molecular dynamics simulations. However, describing the structure and aggregation of large IDPs is challenging due to force field (FF) accuracy and sampling limitations. To cope with the latter, coarse-grained (CG) FFs emerge as a potential alternative at the expense of atomic detail loss. Whereas CG models can accurately describe the structure of the monomer, less is known about aggregation. The latter is key for assessing aggregation pathways and designing aggregation inhibitor drugs. Herein, we investigate the structure and dynamics of α-syn using different resolution CG (Martini3 and Sirah2) and all-atom (Amber99sb and Charmm36m) FFs to gain insight into the differences and resemblances between these models. The dependence of the magnitude of protein-water interactions and the putative need for enhanced sampling (replica exchange) methods in CG simulations are analyzed to distinguish between force field accuracy and sampling limitations. The stability of the CG models of an α-syn fibril was also investigated. Additionally, α-syn aggregation was studied through umbrella sampling for the CG models and CG/all-atom models for an 11-mer peptide (NACore) from an amyloidogenic domain of α-syn. Our results show that despite the α-syn structures of Martini3 and Sirah2 with enhanced protein-water interactions being similar, major differences exist concerning aggregation. The Martini3 fibril is not stable, and the binding free energy of α-syn and NACore is positive, opposite to Sirah2. Sirah2 peptides in a zwitterionic form, in turn, display termini interactions that are too strong, resulting in end-to-end orientation. Sirah2, with enhanced protein-water interactions and neutral termini, provides, however, a peptide aggregation free energy profile similar to that found with all-atom models. Overall, we find that Sirah2 with enhanced protein-water interactions is suitable for studying protein-protein and protein-drug aggregation.
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Affiliation(s)
- Gabriel
F. Martins
- BioISI—Biosystems
and Integrative Sciences Institute, Faculty
of Sciences of the University of Lisbon, C8, Campo Grande, 1749-016 Lisbon, Portugal
| | - Nuno Galamba
- BioISI—Biosystems
and Integrative Sciences Institute, Faculty
of Sciences of the University of Lisbon, C8, Campo Grande, 1749-016 Lisbon, Portugal
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5
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Paul S, Biswas P. Dimerization of Full-Length Aβ-42 Peptide: A Comparison of Different Force Fields and Water Models. Chemphyschem 2024:e202400502. [PMID: 38949117 DOI: 10.1002/cphc.202400502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 06/05/2024] [Accepted: 06/27/2024] [Indexed: 07/02/2024]
Abstract
Among the two isoforms of amyloid-β i. e., Aβ-40 and Aβ-42, Aβ-42 is more toxic due to its increased aggregation propensity. The oligomerization pathways of amyloid-β may be investigated by studying its dimerization process at an atomic level. Intrinsically disordered proteins (IDPs) lack well-defined structures and are associated with numerous neurodegenerative disorders. Molecular dynamics simulations of these proteins are often limited by the choice of parameters due to inconsistencies in the empirically developed protein force fields and water models. To evaluate the accuracy of recently developed force fields for IDPs, we study the dimerization of full-length Aβ-42 in aqueous solution with three different combinations of AMBER force field parameters and water models such as ff14SB/TIP3P, ff19SB/OPC, and ff19SB/TIP3P using classical MD and Umbrella Sampling method. This work may be used as a benchmark to compare the performance of different force fields for the simulations of IDPs.
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Affiliation(s)
- Srijita Paul
- Department of Chemistry, University of Delhi, Delhi, 110007, India
| | - Parbati Biswas
- Department of Chemistry, University of Delhi, Delhi, 110007, India
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6
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Batani G, Vezzani G, Lashchuk S, Allaoui A, Cardamone D, Raso MM, Boero E, Roscioli E, Ridelfi M, Gasperini G, Pizza M, Rossi O, Berlanda Scorza F, Micoli F, Rappuoli R, Sala C. Development of a visual Adhesion/Invasion Inhibition Assay to assess the functionality of Shigella-specific antibodies. Front Immunol 2024; 15:1374293. [PMID: 38680489 PMCID: PMC11045934 DOI: 10.3389/fimmu.2024.1374293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 04/01/2024] [Indexed: 05/01/2024] Open
Abstract
Introduction Shigella is the etiologic agent of a bacillary dysentery known as shigellosis, which causes millions of infections and thousands of deaths worldwide each year due to Shigella's unique lifestyle within intestinal epithelial cells. Cell adhesion/invasion assays have been extensively used not only to identify targets mediating host-pathogen interaction, but also to evaluate the ability of Shigella-specific antibodies to reduce virulence. However, these assays are time-consuming and labor-intensive and fail to assess differences at the single-cell level. Objectives and methods Here, we developed a simple, fast and high-content method named visual Adhesion/Invasion Inhibition Assay (vAIA) to measure the ability of anti-Shigellaantibodies to inhibit bacterial adhesion to and invasion of epithelial cells by using the confocal microscope Opera Phenix. Results We showed that vAIA performed well with a pooled human serum from subjects challenged with S. sonnei and that a specific anti-IpaD monoclonal antibody effectively reduced bacterial virulence in a dose-dependent manner. Discussion vAIA can therefore inform on the functionality of polyclonal and monoclonal responses thereby supporting the discovery of pathogenicity mechanisms and the development of candidate vaccines and immunotherapies. Lastly, this assay is very versatile and may be easily applied to other Shigella species or serotypes and to different pathogens.
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Affiliation(s)
- Giampiero Batani
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Giacomo Vezzani
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Sabrina Lashchuk
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Abdelmounaaim Allaoui
- The Microbiology Laboratory, University Mohammed VI Polytechnic, Ben, Guerir, Morocco
| | - Dario Cardamone
- Data Science for Health Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | | | - Elena Boero
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Emanuele Roscioli
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Matteo Ridelfi
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
| | - Gianmarco Gasperini
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | - Mariagrazia Pizza
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Omar Rossi
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | | | - Francesca Micoli
- GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH), Siena, Italy
| | | | - Claudia Sala
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, Siena, Italy
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7
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Lebedenko OO, Salikov VA, Izmailov SA, Podkorytov IS, Skrynnikov NR. Using NMR diffusion data to validate MD models of disordered proteins: Test case of N-terminal tail of histone H4. Biophys J 2024; 123:80-100. [PMID: 37990496 PMCID: PMC10808029 DOI: 10.1016/j.bpj.2023.11.020] [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: 08/07/2023] [Revised: 10/28/2023] [Accepted: 11/17/2023] [Indexed: 11/23/2023] Open
Abstract
MD simulations can provide uniquely detailed models of intrinsically disordered proteins (IDPs). However, these models need careful experimental validation. The coefficient of translational diffusion Dtr, measurable by pulsed field gradient NMR, offers a potentially useful piece of experimental information related to the compactness of the IDP's conformational ensemble. Here, we investigate, both experimentally and via the MD modeling, the translational diffusion of a 25-residue N-terminal fragment from histone H4 (N-H4). We found that the predicted values of Dtr, as obtained from mean-square displacement of the peptide in the MD simulations, are largely determined by the viscosity of the MD water (which has been reinvestigated as a part of our study). Beyond that, our analysis of the diffusion data indicates that MD simulations of N-H4 in the TIP4P-Ew water give rise to an overly compact conformational ensemble for this peptide. In contrast, TIP4P-D and OPC simulations produce the ensembles that are consistent with the experimental Dtr result. These observations are supported by the analyses of the 15N spin relaxation rates. We also tested a number of empirical methods to predict Dtr based on IDP's coordinates extracted from the MD snapshots. In particular, we show that the popular approach involving the program HYDROPRO can produce misleading results. This happens because HYDROPRO is not intended to predict the diffusion properties of highly flexible biopolymers such as IDPs. Likewise, recent empirical schemes that exploit the relationship between the small-angle x-ray scattering-informed conformational ensembles of IDPs and the respective experimental Dtr values also prove to be problematic. In this sense, the first-principle calculations of Dtr from the MD simulations, such as demonstrated in this work, should provide a useful benchmark for future efforts in this area.
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Affiliation(s)
- Olga O Lebedenko
- Laboratory of Biomolecular NMR, St. Petersburg State University, St. Petersburg, Russia
| | - Vladislav A Salikov
- Laboratory of Biomolecular NMR, St. Petersburg State University, St. Petersburg, Russia
| | - Sergei A Izmailov
- Laboratory of Biomolecular NMR, St. Petersburg State University, St. Petersburg, Russia
| | - Ivan S Podkorytov
- Laboratory of Biomolecular NMR, St. Petersburg State University, St. Petersburg, Russia
| | - Nikolai R Skrynnikov
- Laboratory of Biomolecular NMR, St. Petersburg State University, St. Petersburg, Russia; Department of Chemistry, Purdue University, West Lafayette, Indiana.
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8
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Vijayakumar S, Kumar LL, Borkotoky S, Murali A. The Application of MD Simulation to Lead Identification, Vaccine Design, and Structural Studies in Combat against Leishmaniasis - A Review. Mini Rev Med Chem 2024; 24:1089-1111. [PMID: 37680156 DOI: 10.2174/1389557523666230901105231] [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: 03/13/2023] [Revised: 06/07/2023] [Accepted: 07/14/2023] [Indexed: 09/09/2023]
Abstract
Drug discovery, vaccine design, and protein interaction studies are rapidly moving toward the routine use of molecular dynamics simulations (MDS) and related methods. As a result of MDS, it is possible to gain insights into the dynamics and function of identified drug targets, antibody-antigen interactions, potential vaccine candidates, intrinsically disordered proteins, and essential proteins. The MDS appears to be used in all possible ways in combating diseases such as cancer, however, it has not been well documented as to how effectively it is applied to infectious diseases such as Leishmaniasis. As a result, this review aims to survey the application of MDS in combating leishmaniasis. We have systematically collected articles that illustrate the implementation of MDS in drug discovery, vaccine development, and structural studies related to Leishmaniasis. Of all the articles reviewed, we identified that only a limited number of studies focused on the development of vaccines against Leishmaniasis through MDS. Also, the PCA and FEL studies were not carried out in most of the studies. These two were globally accepted utilities to understand the conformational changes and hence it is recommended that this analysis should be taken up in similar approaches in the future.
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Affiliation(s)
| | | | - Subhomoi Borkotoky
- Department of Biotechnology, Invertis University, Bareilly, Uttar Pradesh, India
| | - Ayaluru Murali
- Department of Bioinformatics, Pondicherry University, Puducherry, India
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9
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Chan-Yao-Chong M, Chan J, Kono H. Benchmarking of force fields to characterize the intrinsically disordered R2-FUS-LC region. Sci Rep 2023; 13:14226. [PMID: 37648703 PMCID: PMC10468508 DOI: 10.1038/s41598-023-40801-6] [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] [Received: 12/26/2022] [Accepted: 08/16/2023] [Indexed: 09/01/2023] Open
Abstract
Intrinsically Disordered Proteins (IDPs) play crucial roles in numerous diseases like Alzheimer's and ALS by forming irreversible amyloid fibrils. The effectiveness of force fields (FFs) developed for globular proteins and their modified versions for IDPs varies depending on the specific protein. This study assesses 13 FFs, including AMBER and CHARMM, by simulating the R2 region of the FUS-LC domain (R2-FUS-LC region), an IDP implicated in ALS. Due to the flexibility of the region, we show that utilizing multiple measures, which evaluate the local and global conformations, and combining them together into a final score are important for a comprehensive evaluation of force fields. The results suggest c36m2021s3p with mTIP3p water model is the most balanced FF, capable of generating various conformations compatible with known ones. In addition, the mTIP3P water model is computationally more efficient than those of top-ranked AMBER FFs with four-site water models. The evaluation also reveals that AMBER FFs tend to generate more compact conformations compared to CHARMM FFs but also more non-native contacts. The top-ranking AMBER and CHARMM FFs can reproduce intra-peptide contacts but underperform for inter-peptide contacts, indicating there is room for improvement.
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Affiliation(s)
- Maud Chan-Yao-Chong
- Molecular Modeling and Simulation (MMS) Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology (QST), 4-9-1, Anagawa, Inage Ward, Chiba City, Chiba, 263-8555, Japan
- Toulouse Biotechnology Institute, TBI, Université de Toulouse, CNRS, INRAE, INSA, 135, Avenue de Rangueil, 31077, Toulouse Cedex 04, France
| | - Justin Chan
- Molecular Modeling and Simulation (MMS) Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology (QST), 4-9-1, Anagawa, Inage Ward, Chiba City, Chiba, 263-8555, Japan
| | - Hidetoshi Kono
- Molecular Modeling and Simulation (MMS) Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology (QST), 4-9-1, Anagawa, Inage Ward, Chiba City, Chiba, 263-8555, Japan.
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Savva L, Platts JA. How Cu(II) binding affects structure and dynamics of α-synuclein revealed by molecular dynamics simulations. J Inorg Biochem 2023; 239:112068. [PMID: 36403437 DOI: 10.1016/j.jinorgbio.2022.112068] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/08/2022] [Accepted: 11/08/2022] [Indexed: 11/15/2022]
Abstract
We report accelerated molecular dynamics simulations of α-Synuclein and its complex with two Cu(II) ions bound to experimentally determined binding sites. Adding two Cu(II) ions, one bound to the N-terminal region and one to the C-terminus, decreases size and flexibility of the peptide while introducing significant new contacts within and between N-terminus and non-Aβ component (NAC). Cu(II) ions also alter the pattern of secondary structure within the peptide, inducing more and longer-lasting elements of secondary structure such as β-strands and hairpins. Free energy surfaces, obtained from reweighting the accelerated molecular dynamics boost potential, further demonstrate the restriction on size and flexibility that results from binding of copper ions.
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Affiliation(s)
- Loizos Savva
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK
| | - James A Platts
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK..
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