1
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Emperador A. PACSAB Server: A Web-Based Tool for the Study of Aggregation and the Conformational Ensemble of Disordered and Folded Proteins. Int J Mol Sci 2024; 25:6021. [PMID: 38892222 PMCID: PMC11172606 DOI: 10.3390/ijms25116021] [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: 04/24/2024] [Revised: 05/20/2024] [Accepted: 05/24/2024] [Indexed: 06/21/2024] Open
Abstract
We present in this article the PACSAB server, which is designed to provide information about the structural ensemble and interactions of both stable and disordered proteins to researchers in the field of molecular biology. The use of this tool does not require any computational skills as the user just needs to upload the structure of the protein to be studied; the server runs a simulation with the PACSAB model, a highly accurate coarse-grained model that is much more efficient than standard molecular dynamics for the exploration of the conformational space of multiprotein systems. The trajectories generated by the simulations based on this model reveal the propensity of the protein under study for aggregation, identify the residues playing a central role in the aggregation process, and reproduce the whole conformational space of disordered proteins. All of this information is shown and can be downloaded from the web page.
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Affiliation(s)
- Agustí Emperador
- Department of Physics, Universitat Politècnica de Catalunya, B4-B5 Campus Nord, Jordi Girona 1-3, 08034 Barcelona, Spain
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2
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Grassmann G, Miotto M, Desantis F, Di Rienzo L, Tartaglia GG, Pastore A, Ruocco G, Monti M, Milanetti E. Computational Approaches to Predict Protein-Protein Interactions in Crowded Cellular Environments. Chem Rev 2024; 124:3932-3977. [PMID: 38535831 PMCID: PMC11009965 DOI: 10.1021/acs.chemrev.3c00550] [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: 07/31/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 04/11/2024]
Abstract
Investigating protein-protein interactions is crucial for understanding cellular biological processes because proteins often function within molecular complexes rather than in isolation. While experimental and computational methods have provided valuable insights into these interactions, they often overlook a critical factor: the crowded cellular environment. This environment significantly impacts protein behavior, including structural stability, diffusion, and ultimately the nature of binding. In this review, we discuss theoretical and computational approaches that allow the modeling of biological systems to guide and complement experiments and can thus significantly advance the investigation, and possibly the predictions, of protein-protein interactions in the crowded environment of cell cytoplasm. We explore topics such as statistical mechanics for lattice simulations, hydrodynamic interactions, diffusion processes in high-viscosity environments, and several methods based on molecular dynamics simulations. By synergistically leveraging methods from biophysics and computational biology, we review the state of the art of computational methods to study the impact of molecular crowding on protein-protein interactions and discuss its potential revolutionizing effects on the characterization of the human interactome.
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Affiliation(s)
- Greta Grassmann
- Department
of Biochemical Sciences “Alessandro Rossi Fanelli”, Sapienza University of Rome, Rome 00185, Italy
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
| | - Mattia Miotto
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
| | - Fausta Desantis
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- The
Open University Affiliated Research Centre at Istituto Italiano di
Tecnologia, Genoa 16163, Italy
| | - Lorenzo Di Rienzo
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
| | - Gian Gaetano Tartaglia
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- Department
of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
- Center
for Human Technologies, Genoa 16152, Italy
| | - Annalisa Pastore
- Experiment
Division, European Synchrotron Radiation
Facility, Grenoble 38043, France
| | - Giancarlo Ruocco
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- Department
of Physics, Sapienza University, Rome 00185, Italy
| | - Michele Monti
- RNA
System Biology Lab, Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - Edoardo Milanetti
- Center
for Life Nano & Neuro Science, Istituto
Italiano di Tecnologia, Rome 00161, Italy
- Department
of Physics, Sapienza University, Rome 00185, Italy
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3
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Nabi F, Ahmad O, Khan A, Hassan MN, Hisamuddin M, Malik S, Chaari A, Khan RH. Natural compound plumbagin based inhibition of hIAPP revealed by Markov state models based on MD data along with experimental validations. Proteins 2024. [PMID: 38497314 DOI: 10.1002/prot.26682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/26/2024] [Accepted: 02/28/2024] [Indexed: 03/19/2024]
Abstract
Human islet amyloid polypeptide (amylin or hIAPP) is a 37 residue hormone co-secreted with insulin from β cells of the pancreas. In patients suffering from type-2 diabetes, amylin self-assembles into amyloid fibrils, ultimately leading to the death of the pancreatic cells. However, a research gap exists in preventing and treating such amyloidosis. Plumbagin, a natural compound, has previously been demonstrated to have inhibitory potential against insulin amyloidosis. Our investigation unveils collapsible regions within hIAPP that, upon collapse, facilitates hydrophobic and pi-pi interactions, ultimately leading to aggregation. Intriguingly plumbagin exhibits the ability to bind these specific collapsible regions, thereby impeding the aforementioned interactions that would otherwise drive hIAPP aggregation. We have used atomistic molecular dynamics approach to determine secondary structural changes. MSM shows metastable states forming native like hIAPP structure in presence of PGN. Our in silico results concur with in vitro results. The ThT assay revealed a striking 50% decrease in fluorescence intensity at a 1:1 ratio of hIAPP to Plumbagin. This finding suggests a significant inhibition of amyloid fibril formation by plumbagin, as ThT fluorescence directly correlates with the presence of these fibrils. Further TEM images revealed disappearance of hIAPP fibrils in plumbagin pre-treated hIAPP samples. Also, we have shown that plumbagin disrupts the intermolecular hydrogen bonding in hIAPP fibrils leading to an increase in the average beta strand spacing, thereby causing disaggregation of pre-formed fibrils demonstrating overall disruption of the aggregation machinery of hIAPP. Our work is the first to report a detailed atomistic simulation of 22 μs for hIAPP. Overall, our studies put plumbagin as a potential candidate for both preventive and therapeutic candidate for hIAPP amyloidosis.
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Affiliation(s)
- Faisal Nabi
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Owais Ahmad
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Adeeba Khan
- Zakir Hussain College of Engineering and Technology, Aligarh Muslim University, Aligarh, India
| | - Md Nadir Hassan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Malik Hisamuddin
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Sadia Malik
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Ali Chaari
- Premedical Division, Weill Cornell Medicine Qatar, Qatar Foundation, Doha, Qatar
| | - Rizwan Hasan Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
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4
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Sha H, Zhu F. Hexagonal Lattices of HIV Capsid Proteins Explored by Simulations Based on a Thermodynamically Consistent Model. J Phys Chem B 2024; 128:960-972. [PMID: 38251836 DOI: 10.1021/acs.jpcb.3c06881] [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: 01/23/2024]
Abstract
HIV capsid proteins (CAs) may self-assemble into a variety of shapes under in vivo and in vitro conditions. Here, we employed simulations based on a residue-level coarse-grained (CG) model with full conformational flexibility to investigate hexagonal lattices, which are the underlying structural pattern for CA aggregations. Facilitated by enhanced sampling simulations to rigorously calculate CA dimerization and polymerization affinities, we calibrated our model to reproduce the experimentally measured affinities. Using the calibrated model, we performed unbiased simulations on several large systems consisting of 1512 CA subunits, allowing reversible binding and unbinding of the CAs in a thermodynamically consistent manner. In one simulation, a preassembled hexagonal CA sheet developed spontaneous curvatures reminiscent of those observed in experiments, and the edges of the sheet exhibited local curvatures larger than those of the interior. In other simulations starting with randomly distributed CAs at different concentrations, existing CA assemblies grew by binding free capsomeres to the edges and by merging with other assemblies. At high CA concentrations, rapid establishment of predominant aggregates was followed by much slower adjustments toward more regular hexagonal lattices, with increasing numbers of intact CA hexamers and pentamers being formed. Our approach of adapting a general CG model to specific systems by using experimental binding data represents a practical and effective strategy for simulating and elucidating intricate protein aggregations.
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Affiliation(s)
- Hao Sha
- Department of Physics, Indiana University─Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Fangqiang Zhu
- Department of Physics, Indiana University─Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
- Biochemical and Biophysical Systems Group, Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
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5
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Saurabh S, Li Z, Hollowell P, Waigh T, Li P, Webster J, Seddon JM, Kalonia C, Lu JR, Bresme F. Structure and interaction of therapeutic proteins in solution: a combined simulation and experimental study. Mol Phys 2023; 121:e2236248. [PMID: 38107421 PMCID: PMC10721229 DOI: 10.1080/00268976.2023.2236248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/30/2023] [Indexed: 12/19/2023]
Abstract
The aggregation of therapeutic proteins in solution has attracted significant interest, driving efforts to understand the relationship between microscopic structural changes and protein-protein interactions determining aggregation processes in solution. Additionally, there is substantial interest in being able to predict aggregation based on protein structure as part of molecular developability assessments. Molecular Dynamics provides theoretical tools to complement experimental studies and to interrogate and identify the microscopic mechanisms determining aggregation. Here we perform all-atom MD simulations to study the structure and inter-protein interaction of the Fab and Fc fragments of the monoclonal antibody (mAb) COE3. We unravel the role of ion-protein interactions in building the ionic double layer and determining effective inter-protein interaction. Further, we demonstrate, using various state-of-the-art force fields (charmm, gromos, amber, opls/aa), that the protein solvation, ionic structure and protein-protein interaction depend significantly on the force field parameters. We perform SANS and Static Light Scattering experiments to assess the accuracy of the different forcefields. Comparison of the simulated and experimental results reveal significant differences in the forcefields' performance, particularly in their ability to predict the protein size in solution and inter-protein interactions quantified through the second virial coefficients. In addition, the performance of the forcefields is correlated with the protein hydration structure.
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Affiliation(s)
- Suman Saurabh
- Department of Chemistry, Molecular Sciences Research Hub Imperial College, London, United Kingdom
| | - Zongyi Li
- Biological Physics Group, School of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Manchester, UK
| | - Peter Hollowell
- Biological Physics Group, School of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Manchester, UK
| | - Thomas Waigh
- Biological Physics Group, School of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Manchester, UK
- Photon Science Institute, The University of Manchester, Manchester, UK
| | - Peixun Li
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot, UK
| | - John Webster
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot, UK
| | - John M. Seddon
- Department of Chemistry, Molecular Sciences Research Hub Imperial College, London, United Kingdom
| | - Cavan Kalonia
- Dosage Form Design and Development, BioPharmaceutical Development, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Jian R. Lu
- Biological Physics Group, School of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Manchester, UK
| | - Fernando Bresme
- Department of Chemistry, Molecular Sciences Research Hub Imperial College, London, United Kingdom
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6
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Martin J, Frezza E. A dynamical view of protein-protein complexes: Studies by molecular dynamics simulations. Front Mol Biosci 2022; 9:970109. [PMID: 36275619 PMCID: PMC9583002 DOI: 10.3389/fmolb.2022.970109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Protein-protein interactions are at the basis of many protein functions, and the knowledge of 3D structures of protein-protein complexes provides structural, mechanical and dynamical pieces of information essential to understand these functions. Protein-protein interfaces can be seen as stable, organized regions where residues from different partners form non-covalent interactions that are responsible for interaction specificity and strength. They are commonly described as a peripheral region, whose role is to protect the core region that concentrates the most contributing interactions, from the solvent. To get insights into the dynamics of protein-protein complexes, we carried out all-atom molecular dynamics simulations in explicit solvent on eight different protein-protein complexes of different functional class and interface size by taking into account the bound and unbound forms. On the one hand, we characterized structural changes upon binding of the proteins, and on the other hand we extensively analyzed the interfaces and the structural waters involved in the binding. Based on our analysis, in 6 cases out of 8, the interfaces rearranged during the simulation time, in stable and long-lived substates with alternative residue-residue contacts. These rearrangements are not restricted to side-chain fluctuations in the periphery but also affect the core interface. Finally, the analysis of the waters at the interface and involved in the binding pointed out the importance to take into account their role in the estimation of the interaction strength.
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Affiliation(s)
- Juliette Martin
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, UMR 5086 MMSB, Lyon, France
- *Correspondence: Juliette Martin, ; Elisa Frezza,
| | - Elisa Frezza
- Université Paris Cité, CiTCoM, Paris, France
- *Correspondence: Juliette Martin, ; Elisa Frezza,
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7
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Liu D, Qiu Y, Li Q, Zhang H. Atomistic Simulation of Lysozyme in Solutions Crowded by Tetraethylene Glycol: Force Field Dependence. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27072110. [PMID: 35408509 PMCID: PMC9000840 DOI: 10.3390/molecules27072110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 11/16/2022]
Abstract
The behavior of biomolecules in crowded environments remains largely unknown due to the accuracy of simulation models and the limited experimental data for comparison. Here we chose a small crowder of tetraethylene glycol (PEG-4) to investigate the self-crowding of PEG-4 solutions and molecular crowding effects on the structure and diffusion of lysozyme at varied concentrations from dilute water to pure PEG-4 liquid. Two Amber-like force fields of Amber14SB and a99SB-disp were examined with TIP3P (fast diffusivity and low viscosity) and a99SB-disp (slow diffusivity and high viscosity) water models, respectively. Compared to the Amber14SB protein simulations, the a99SB-disp model yields more coordinated water and less PEG-4 molecules, less intramolecular hydrogen bonds (HBs), more protein-water HBs, and less protein-PEG HBs as well as stronger interactions and more hydrophilic and less hydrophobic contacts with solvent molecules. The a99SB-disp model offers comparable protein-solvent interactions in concentrated PEG-4 solutions to that in pure water. The PEG-4 crowding leads to a slow-down in the diffusivity of water, PEG-4, and protein, and the decline in the diffusion from atomistic simulations is close to or faster than the hard sphere model that neglects attractive interactions. Despite these differences, the overall structure of lysozyme appears to be maintained well at different PEG-4 concentrations for both force fields, except a slightly large deviation at 370 K at low concentrations with the a99SB-disp model. This is mainly attributed to the strong intramolecular interactions of the protein in the Amber14SB force field and to the large viscosity of the a99SB-disp water model. The results indicate that the protein force fields and the viscosity of crowder solutions affect the simulation of biomolecules under crowding conditions.
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8
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Emperador A. Accurate Description of Protein-Protein Recognition and Protein Aggregation with the Implicit-Solvent-Based PACSAB Protein Model. Polymers (Basel) 2021; 13:polym13234172. [PMID: 34883675 PMCID: PMC8659885 DOI: 10.3390/polym13234172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/12/2021] [Accepted: 11/18/2021] [Indexed: 02/01/2023] Open
Abstract
We used the PACSAB protein model, based on the implicit solvation approach, to simulate protein–protein recognition and study the effect of helical structure on the association of aggregating peptides. After optimization, the PACSAB force field was able to reproduce correctly both the correct binding interface in ubiquitin dimerization and the conformational ensemble of the disordered protein activator for hormone and retinoid receptor (ACTR). The PACSAB model allowed us to predict the native binding of ACTR with its binding partner, reproducing the refolding upon binding mechanism of the disordered protein.
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Affiliation(s)
- Agustí Emperador
- Department of Physics, Universitat Politècnica de Catalunya, B4-B5 Campus Nord, Jordi Girona 1-3, 08034 Barcelona, Spain
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9
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Qiu Y, Shan W, Zhang H. Force Field Benchmark of Amino Acids. 3. Hydration with Scaled Lennard-Jones Interactions. J Chem Inf Model 2021; 61:3571-3582. [PMID: 34185520 DOI: 10.1021/acs.jcim.1c00339] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Classical protein force fields were reported with too weak protein-water interactions relative to protein-protein interactions, leading to more compact structures and artificial protein aggregation. Here we investigated the impacts of scaled Lennard-Jones (LJ) interactions on the hydration of amino acids and the simulation of folded and intrinsically disordered proteins (IDPs). The obtained optimal scaling parameters reproduce accurately hydration free energies of neutral amino acid side chain analogues and do not affect the compactness and structural stability of folded proteins significantly. The scaling leads to less compact IDPs and varies from case to case. Strengthening the interactions between protein and water oxygen or hydrogen atoms by increasing the interacting LJ well depth (ε) appears more effective than weakening protein-protein interactions by reducing the interacting dispersion coefficients (C6). We demonstrate that weakening water-water interactions is a solution as well to obtaining more favorable protein-water interactions in an indirect way, although modern force fields like Amber ff19SB and a99SB-disp tend to use water models with strong water-water interactions. This is likely a compromise between strong protein-protein interactions and strong water-water interactions. Independent optimization of protein force fields and water models is therefore needed to make both interactions more close to reality, leading to good accuracy without bias or scaling.
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Affiliation(s)
- Yejie Qiu
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Wenjie Shan
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Haiyang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
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10
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Assessment of transferable forcefields for protein simulations attests improved description of disordered states and secondary structure propensities, and hints at multi-protein systems as the next challenge for optimization. Comput Struct Biotechnol J 2021; 19:2626-2636. [PMID: 34025949 PMCID: PMC8120800 DOI: 10.1016/j.csbj.2021.04.050] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 01/02/2023] Open
Abstract
Continuous assessment of transferable forcefields for molecular simulations is essential to identify their weaknesses and direct improvement efforts. The latest efforts focused on better describing disordered proteins while retaining proper description of folded domains, important because forcefields of the previous generations produce overly compact disordered states. Such improvements should additionally alleviate the related problem of over-stabilized protein–protein interactions, which has been largely overlooked. Here we evaluated three state-of-the-art forcefields, current flagships of their respective developers, optimized for ordered and disordered proteins: CHARMM36m with its recommended corrected TIP3P* water, ff19SB with the recommended OPC water, and the 2019 a99SBdisp forcefield by D. E. Shaw Research with its modified TIP4P water; plus ff14SB with TIP3P as an example of the former generation of forcefields. Our evaluation entailed simulations of (i) multiple copies of a protein that is highly soluble yet undergoes weak dimerization, (ii) a disordered peptide with low, well-characterized alpha helical propensity, and (iii) a peptide known to form insoluble β-aggregates. Our results recapitulate ff14SB-TIP3P over-stabilizing aggregates and secondary structures and place a99SBdisp-TIP4PD at the other end i.e. predicting overly weak intermolecular interactions despite reasonably predicting secondary structure propensities. In-between, CHARMM36m-TIP3P* still over-stabilizes aggregates but predicts residue-wise alpha helical propensities in solution slightly better than ff19SB-OPC, while ff19SB-OPC poses the best prediction of weak dimerization of the soluble protein still predicting aggregation of the β-peptides. This independent assessment shows that the claimed forcefield improvements are real, but also that a right balance between noncovalent attraction and repulsion has not yet been reached. We thus propose developers to consider systems like those tested here in their forcefield tuning protocols. Last, the good performance of CHARMM36m-TIP3P* further shows that tuning 3-point water models might still be an alternative to the more costly 4-point models like OPC and TIP4PD.
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11
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Pedebos C, Smith IPS, Boags A, Khalid S. The hitchhiker's guide to the periplasm: Unexpected molecular interactions of polymyxin B1 in E. coli. Structure 2021; 29:444-456.e2. [PMID: 33577754 DOI: 10.1016/j.str.2021.01.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/11/2020] [Accepted: 01/21/2021] [Indexed: 12/19/2022]
Abstract
The periplasm of Gram-negative bacteria is a complex, highly crowded molecular environment. Little is known about how antibiotics move across the periplasm and the interactions they experience. Here, atomistic molecular dynamics simulations are used to study the antibiotic polymyxin B1 within models of the periplasm, which are crowded to different extents. We show that PMB1 is likely to be able to "hitchhike" within the periplasm by binding to lipoprotein carriers-a previously unreported passive transport route. The simulations reveal that PMB1 forms both transient and long-lived interactions with proteins, osmolytes, lipids of the outer membrane, and the cell wall, and is rarely uncomplexed when in the periplasm. Furthermore, it can interfere in the conformational dynamics of native proteins. These are important considerations for interpreting its mechanism of action and are likely to also hold for other antibiotics that rely on diffusion to cross the periplasm.
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Affiliation(s)
- Conrado Pedebos
- School of Chemistry, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
| | - Iain Peter Shand Smith
- School of Chemistry, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
| | - Alister Boags
- School of Chemistry, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK
| | - Syma Khalid
- School of Chemistry, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK.
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12
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Effect of the Water Model in Simulations of Protein-Protein Recognition and Association. Polymers (Basel) 2021; 13:polym13020176. [PMID: 33419008 PMCID: PMC7825341 DOI: 10.3390/polym13020176] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/24/2020] [Accepted: 12/29/2020] [Indexed: 12/24/2022] Open
Abstract
We study self-association of ubiquitin and the disordered protein ACTR using the most commonly used water models. We find that dissociation events are found only with TIP4P-EW and TIP4P/2005, while the widely used TIP3P water model produces straightforward aggregation of the molecules due to the absence of dissociation events. We also find that TIP4P/2005 is the only water model that reproduces the fast association/dissociation dynamics of ubiquitin and best identifies its binding surface. Our results show the critical role of the water model in the description of protein–protein interactions and binding.
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13
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Schauperl M, Kantonen SM, Wang LP, Gilson MK. Data-driven analysis of the number of Lennard-Jones types needed in a force field. Commun Chem 2020; 3:173. [PMID: 34295996 PMCID: PMC8294475 DOI: 10.1038/s42004-020-00395-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/28/2020] [Indexed: 01/12/2023] Open
Abstract
Force fields used in molecular simulations contain numerical parameters, such as Lennard-Jones (LJ) parameters, which are assigned to the atoms in a molecule based on a classification of their chemical environments. The number of classes, or types, should be no more than needed to maximize agreement with experiment, as parsimony avoids overfitting and simplifies parameter optimization. However, types have historically been crafted based largely on chemical intuition, so current force fields may contain more types than needed. In this study, we seek the minimum number of LJ parameter types needed to represent key properties of organic liquids. We find that highly competitive force field accuracy is obtained with minimalist sets of LJ types; e.g. two H types and one type apiece for C, O, and N atoms. We also find that the fitness surface has multiple minima, which can lead to local trapping of the optimizer.
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Affiliation(s)
- Michael Schauperl
- Skaggs School of Pharmacy and Pharmaceutical Sciences, 9500 Gilman Drive, MC0751, University of California, San Diego, CA 92093-0751 USA
| | - Sophie M Kantonen
- Skaggs School of Pharmacy and Pharmaceutical Sciences, 9500 Gilman Drive, MC0751, University of California, San Diego, CA 92093-0751 USA
| | - Lee-Ping Wang
- Department of Chemistry, University of California, Davis, CA 95616 USA
| | - Michael K Gilson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, 9500 Gilman Drive, MC0751, University of California, San Diego, CA 92093-0751 USA
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14
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Li ZY, Guo HT, Calderón-Mantilla G, He JJ, Wang JL, Bonev BB, Zhu XQ, Elsheikha HM. Immunostimulatory efficacy and protective potential of putative TgERK7 protein in mice experimentally infected by Toxoplasma gondii. Int J Med Microbiol 2020; 310:151432. [PMID: 32654774 DOI: 10.1016/j.ijmm.2020.151432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 05/10/2020] [Accepted: 05/23/2020] [Indexed: 12/11/2022] Open
Abstract
The extracellular signal-regulated kinases (ERKs) serve as important determinants of cellular signal transduction pathways, and hence may play important roles during infections. Previous work suggested that putative ERK7 of Toxoplasma gondii is required for efficient intracellular replication of the parasite. However, the antigenic and immunostimulatory properties of TgERK7 protein remain unknown. The objective of this study was to produce a recombinant TgERK7 protein in vitro and to evaluate its effect on the induction of humoral and T cell-mediated immune responses against T. gondii infection in BALB/c mice. Immunization using TgERK7 mixed with Freund's adjuvants significantly increased the ratio of CD3e+CD4+ T/CD3e+CD8a+ T lymphocytes in spleen and elevated serum cytokines (IFN-γ, IL-2, IL-4, IL-10, IL-12p70, IL-23, MCP-1, and TNF-α) in immunized mice compared to control mice. On the contrary, immunization did not induce high levels of serum IgG antibodies. Five predicted peptides of TgERK7 were synthesized and conjugated with KLH and used to analyze the antibody specificity in the sera of immunized mice. We detected a progressive increase in the antibody level only against TgERK7 peptide A (DEVDKHVLRKYD). Antibody raised against this peptide significantly decreased intracellular proliferation of T. gondii in vitro, suggesting that peptide A can potentially induce a protective antibody response. We also showed that immunization improved the survival rate of mice challenged with a virulent strain and significantly reduced the parasite cyst burden within the brains of chronically infected mice. Our data show that TgERK7-based immunization induced TgERK7 peptide A-specific immune responses that can impart protective immunity against T. gondii infection. The therapeutic potential of targeting ERK7 signaling pathway for future toxoplasmosis treatment is warranted.
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Affiliation(s)
- Zhong-Yuan Li
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, College of Basic Medicine, Guilin Medical University, Guilin, Guangxi, 541199, China; State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, 730046, China; College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui, 230036, China
| | - Hai-Ting Guo
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, College of Basic Medicine, Guilin Medical University, Guilin, Guangxi, 541199, China
| | - Guillermo Calderón-Mantilla
- Universidad de La Sabana, Campus del Puente del Común, Km. 7, Autopista Norte de Bogotá. Chía, Cundinamarca, Colombia
| | - Jun-Jun He
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, 730046, China
| | - Jin-Lei Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, 730046, China
| | - Boyan B Bonev
- School of life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, 730046, China.
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
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15
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Abstract
The restrained electrostatic potential (RESP) approach is a highly regarded and widely used method of assigning partial charges to molecules for simulations. RESP uses a quantum-mechanical method that yields fortuitous overpolarization and thereby accounts only approximately for self-polarization of molecules in the condensed phase. Here we present RESP2, a next generation of this approach, where the polarity of the charges is tuned by a parameter, δ, which scales the contributions from gas- and aqueous-phase calculations. When the complete non-bonded force field model, including Lennard-Jones parameters, is optimized to liquid properties, improved accuracy is achieved, even with this reduced set of five Lennard-Jones types. We argue that RESP2 with δ≈0.6 (60% aqueous, 40% gas-phase charges) is an accurate and robust method of generating partial charges, and that a small set of Lennard-Jones types is good starting point for a systematic re-optimization of this important non-bonded term.
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16
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Bashardanesh Z, Elf J, Zhang H, van der Spoel D. Rotational and Translational Diffusion of Proteins as a Function of Concentration. ACS OMEGA 2019; 4:20654-20664. [PMID: 31858051 PMCID: PMC6906769 DOI: 10.1021/acsomega.9b02835] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/14/2019] [Indexed: 05/21/2023]
Abstract
Atomistic simulations of three different proteins at different concentrations are performed to obtain insight into protein mobility as a function of protein concentration. We report on simulations of proteins from diluted to the physiological water concentration (about 70% of the mass). First, the viscosity was computed and found to increase by a factor of 7-9 going from pure water to the highest protein concentration, in excellent agreement with in vivo nuclear magnetic resonance results. At a physiological concentration of proteins, the translational diffusion is found to be slowed down to about 30% of the in vitro values. The slow-down of diffusion found here using atomistic models is slightly more than that of a hard sphere model that neglects the electrostatic interactions. Interestingly, rotational diffusion of proteins is slowed down somewhat more (by about 80-95% compared to in vitro values) than translational diffusion, in line with experimental findings and consistent with the increased viscosity. The finding that rotation is retarded more than translation is attributed to solvent-separated clustering. No direct interactions between the proteins are found, and the clustering can likely be attributed to dispersion interactions that are stronger between proteins than between protein and water. Based on these simulations, we can also conclude that the internal dynamics of the proteins in our study are affected only marginally under crowding conditions, and the proteins become somewhat more stable at higher concentrations. Simulations were performed using a force field that was tuned for dealing with crowding conditions by strengthening the protein-water interactions. This force field seems to lead to a reproducible partial unfolding of an α-helix in one of the proteins, an effect that was not observed in the unmodified force field.
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Affiliation(s)
- Zahedeh Bashardanesh
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
| | - Johan Elf
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
| | - Haiyang Zhang
- Department
of Biological Science and Engineering, School of Chemistry and Biological
Engineering, University of Science and Technology
Beijing, 100083 Beijing, China
| | - David van der Spoel
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
- E-mail: . Phone: +46 18 4714205
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17
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Oliveira Bortot L, Bashardanesh Z, van der Spoel D. Making Soup: Preparing and Validating Models of the Bacterial Cytoplasm for Molecular Simulation. J Chem Inf Model 2019; 60:322-331. [DOI: 10.1021/acs.jcim.9b00971] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Leandro Oliveira Bortot
- Laboratory of Biological Physics, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, 14040-903 Ribeirão Preto-SP, Brazil
| | - Zahedeh Bashardanesh
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Box 596, SE-75124 Uppsala, Sweden
| | - David van der Spoel
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Box 596, SE-75124 Uppsala, Sweden
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18
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Characterisation of the Dynamic Interactions between Complex
N
‐Glycans and Human CD22. Chembiochem 2019; 21:129-140. [DOI: 10.1002/cbic.201900295] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Indexed: 12/21/2022]
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19
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Li ZL, Buck M. Modified Potential Functions Result in Enhanced Predictions of a Protein Complex by All-Atom Molecular Dynamics Simulations, Confirming a Stepwise Association Process for Native Protein-Protein Interactions. J Chem Theory Comput 2019; 15:4318-4331. [PMID: 31241940 DOI: 10.1021/acs.jctc.9b00195] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The relative prevalence of native protein-protein interactions (PPIs) are the cornerstone for understanding the structure, dynamics and mechanisms of function of protein complexes. In this study, we develop a scheme for scaling the protein-water interaction in the CHARMM36 force field, in order to better fit the solvation free energy of amino acids side-chain analogues. We find that the molecular dynamics simulation with the scaled force field, CHARMM36s, as well as a recently released version, CHARMM36m, effectively improve on the overly sticky association of proteins, such as ubiquitin. We investigate the formation of a heterodimer protein complex between the SAM domains of the EphA2 receptor and the SHIP2 enzyme by performing a combined total of 48 μs simulations with the different potential functions. While the native SAM heterodimer is only predicted at a low rate of 6.7% with the original CHARMM36 force field, the yield is increased to 16.7% with CHARMM36s, and to 18.3% with CHARMM36m. By analyzing the 25 native SAM complexes formed in the simulations, we find that their formation involves a preorientation guided by Coulomb interactions, consistent with an electrostatic steering mechanism. In 12 cases, the complex could directly transform to the native protein interaction surfaces with only small adjustments in domain orientation. In the other 13 cases, orientational and/or translational adjustments are needed to reach the native complex. Although the tendency for non-native complexes to dissociate has nearly doubled with the modified potential functions, a dissociation followed by a reassociation to the correct complex structure is still rare. Instead, the remaining non-native complexes undergo configurational changes/surface searching, which, however, rarely leads to native structures on a time scale of 250 ns. These observations provide a rich picture of the mechanisms of protein-protein complex formation and suggest that computational predictions of native complex PPIs could be improved further.
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Affiliation(s)
- Zhen-Lu Li
- Department of Physiology and Biophysics , Case Western Reserve University, School of Medicine , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Matthias Buck
- Department of Physiology and Biophysics , Case Western Reserve University, School of Medicine , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States.,Departments of Pharmacology and Neurosciences, and Case Comprehensive Cancer Center , Case Western Reserve University, School of Medicine , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
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20
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Zerze GH, Zheng W, Best RB, Mittal J. Evolution of All-Atom Protein Force Fields to Improve Local and Global Properties. J Phys Chem Lett 2019; 10:2227-2234. [PMID: 30990694 PMCID: PMC7507668 DOI: 10.1021/acs.jpclett.9b00850] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Experimental studies on intrinsically disordered and unfolded proteins have shown that in isolation they typically have low populations of secondary structure and exhibit distance scalings suggesting that they are at near-theta-solvent conditions. Until recently, however, all-atom force fields failed to reproduce these fundamental properties of intrinsically disordered proteins (IDPs). Recent improvements by refining against ensemble-averaged experimental observables for polypeptides in aqueous solution have addressed deficiencies including secondary structure bias, global conformational properties, and thermodynamic parameters of biophysical reactions such as folding and collapse. To date, studies utilizing these improved all-atom force fields have mostly been limited to a small set of unfolded or disordered proteins. Here, we present data generated for a diverse library of unfolded or disordered proteins using three progressively improved generations of Amber03 force fields, and we explore how global and local properties are affected by each successive change in the force field. We find that the most recent force field refinements significantly improve the agreement of the global properties such as radii of gyration and end-to-end distances with experimental estimates. However, these global properties are largely independent of the local secondary structure propensity. This result stresses the need to validate force fields with reference to a combination of experimental data providing information about both local and global structure formation.
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Affiliation(s)
- Gül H Zerze
- Department of Chemical and Biomolecular Engineering , Lehigh University , Bethlehem , Pennsylvania 18015 , United States
| | - Wenwei Zheng
- College of Integrative Sciences and Arts , Arizona State University , Mesa , Arizona 85212 , United States
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Jeetain Mittal
- Department of Chemical and Biomolecular Engineering , Lehigh University , Bethlehem , Pennsylvania 18015 , United States
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21
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Abstract
Most proteins associate with other proteins to function, forming complexes that are central to almost all physiological processes. Determining the structures of these complexes and understanding how they associate are problems of fundamental importance. Using long-timescale molecular dynamics simulations, some performed using a new enhanced sampling method, we observed spontaneous association and dissociation of five protein–protein systems to and from their experimentally determined native complexes. By analyzing the simulations of these five systems, which include members of diverse structural and functional classes, we are able to draw general mechanistic conclusions about protein association. Despite the biological importance of protein–protein complexes, determining their structures and association mechanisms remains an outstanding challenge. Here, we report the results of atomic-level simulations in which we observed five protein–protein pairs repeatedly associate to, and dissociate from, their experimentally determined native complexes using a molecular dynamics (MD)–based sampling approach that does not make use of any prior structural information about the complexes. To study association mechanisms, we performed additional, conventional MD simulations, in which we observed numerous spontaneous association events. A shared feature of native association for these five structurally and functionally diverse protein systems was that if the proteins made contact far from the native interface, the native state was reached by dissociation and eventual reassociation near the native interface, rather than by extensive interfacial exploration while the proteins remained in contact. At the transition state (the conformational ensemble from which association to the native complex and dissociation are equally likely), the protein–protein interfaces were still highly hydrated, and no more than 20% of native contacts had formed.
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22
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Carballo-Pacheco M, Ismail AE, Strodel B. On the Applicability of Force Fields To Study the Aggregation of Amyloidogenic Peptides Using Molecular Dynamics Simulations. J Chem Theory Comput 2018; 14:6063-6075. [PMID: 30336669 DOI: 10.1021/acs.jctc.8b00579] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular dynamics simulations play an essential role in understanding biomolecular processes such as protein aggregation at temporal and spatial resolutions which are not attainable by experimental methods. For a correct modeling of protein aggregation, force fields must accurately represent molecular interactions. Here, we study the effect of five different force fields on the oligomer formation of Alzheimer's Aβ16-22 peptide and two of its mutants: Aβ16-22(F19V,F20V), which does not form fibrils, and Aβ16-22(F19L) which forms fibrils faster than the wild type. We observe that while oligomer formation kinetics depends strongly on the force field, structural properties, such as the most relevant protein-protein contacts, are similar between them. The oligomer formation kinetics obtained with different force fields differ more from each other than the kinetics between aggregating and nonaggregating peptides simulated with a single force field. We discuss the difficulties in comparing atomistic simulations of amyloid oligomer formation with experimental observables.
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Affiliation(s)
- Martín Carballo-Pacheco
- Institute of Complex Systems: Structural Biochemistry (ICS-6) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany.,AICES Graduate School , RWTH Aachen University , Schinkelstraße 2 , 52062 Aachen , Germany
| | - Ahmed E Ismail
- AICES Graduate School , RWTH Aachen University , Schinkelstraße 2 , 52062 Aachen , Germany.,Aachener Verfahrenstechnik, Faculty of Mechanical Engineering , RWTH Aachen University , Schinkelstraße 2 , 52062 Aachen , Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany.,Institute of Theoretical and Computational Chemistry , Heinrich Heine University Düsseldorf , Universitätstrasse 1 , 40225 Düsseldorf , Germany
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23
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Bashardanesh Z, van der Spoel D. Impact of Dispersion Coefficient on Simulations of Proteins and Organic Liquids. J Phys Chem B 2018; 122:8018-8027. [DOI: 10.1021/acs.jpcb.8b05770] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Zahedeh Bashardanesh
- Uppsala Center for Computational Chemistry, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, P.O. Box 596, SE-75124 Uppsala, Sweden
| | - David van der Spoel
- Uppsala Center for Computational Chemistry, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, P.O. Box 596, SE-75124 Uppsala, Sweden
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24
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Zhang H, Jiang Y, Cui Z, Yin C. Force Field Benchmark of Amino Acids. 2. Partition Coefficients between Water and Organic Solvents. J Chem Inf Model 2018; 58:1669-1681. [DOI: 10.1021/acs.jcim.8b00493] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Haiyang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Yang Jiang
- Beijing Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Box 53, 100029 Beijing, China
| | - Ziheng Cui
- Beijing Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Box 53, 100029 Beijing, China
| | - Chunhua Yin
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
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25
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26
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Dongmo Foumthuim CJ, Corazza A, Esposito G, Fogolari F. Molecular dynamics simulations of β2-microglobulin interaction with hydrophobic surfaces. MOLECULAR BIOSYSTEMS 2018; 13:2625-2637. [PMID: 29051937 DOI: 10.1039/c7mb00464h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hydrophobic surfaces are known to adsorb and unfold proteins, a process that has been studied only for a few proteins. Here we address the interaction of β2-microglobulin, a paradigmatic protein for the study of amyloidogenesis, with hydrophobic surfaces. A system with 27 copies of the protein surrounded by a model cubic hydrophobic box is studied by implicit solvent molecular dynamics simulations. Most proteins adsorb on the walls of the box without major distortions in local geometry, whereas free molecules maintain proper structures and fluctuations as observed in explicit solvent molecular dynamics simulations. The major conclusions from the simulations are as follows: (i) the adopted implicit solvent model is adequate to describe protein dynamics and thermodynamics; (ii) adsorption occurs readily and is irreversible on the simulated timescale; (iii) the regions most involved in molecular encounters and stable interactions with the walls are the same as those that are important in protein-protein and protein-nanoparticle interactions; (iv) unfolding following adsorption occurs at regions found to be flexible by both experiments and simulations; (v) thermodynamic analysis suggests a very large contribution from van der Waals interactions, whereas unfavorable electrostatic interactions are not found to contribute much to adsorption energy. Surfaces with different degrees of hydrophobicity may occur in vivo. Our simulations show that adsorption is a fast and irreversible process which is accompanied by partial unfolding. The results and the thermodynamic analysis presented here are consistent with and rationalize previous experimental work.
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27
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Fogolari F, Maloku O, Dongmo Foumthuim CJ, Corazza A, Esposito G. PDB2ENTROPY and PDB2TRENT: Conformational and Translational–Rotational Entropy from Molecular Ensembles. J Chem Inf Model 2018; 58:1319-1324. [DOI: 10.1021/acs.jcim.8b00143] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Federico Fogolari
- Dipartimento di Scienze Matematiche, Informatiche e Fisiche (DIMF), University of Udine, Via delle Scienze 206, 33100 Udine, Italy
- Istituto Nazionale Biostrutture e Biosistemi, Viale medaglie d’Oro 305, 00136 Roma, Italy
| | - Ornela Maloku
- Dipartimento di Scienze Matematiche, Informatiche e Fisiche (DIMF), University of Udine, Via delle Scienze 206, 33100 Udine, Italy
| | | | - Alessandra Corazza
- Istituto Nazionale Biostrutture e Biosistemi, Viale medaglie d’Oro 305, 00136 Roma, Italy
- Dipartimento di Area Medica (DAME), University of Udine, Piazzale Kolbe 4, 33100 Udine, Italy
| | - Gennaro Esposito
- Dipartimento di Scienze Matematiche, Informatiche e Fisiche (DIMF), University of Udine, Via delle Scienze 206, 33100 Udine, Italy
- Istituto Nazionale Biostrutture e Biosistemi, Viale medaglie d’Oro 305, 00136 Roma, Italy
- Science and Math Division, New York University at Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates
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28
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Dynamics and Thermodynamics of Transthyretin Association from Molecular Dynamics Simulations. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7480749. [PMID: 29967786 PMCID: PMC6008865 DOI: 10.1155/2018/7480749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/06/2018] [Indexed: 12/15/2022]
Abstract
Molecular dynamics simulations are used in this work to probe the structural stability and the dynamics of engineered mutants of transthyretin (TTR), i.e., the double mutant F87M/L110M (MT-TTR) and the triple mutant F87M/L110M/S117E (3M-TTR), in relation to wild-type. Free energy analysis from end-point simulations and statistical effective energy functions are used to analyze trajectories, revealing that mutations do not have major impact on protein structure but rather on protein association, shifting the equilibria towards dissociated species. The result is confirmed by the analysis of 3M-TTR which shows dissociation within the first 10 ns of the simulation, indicating that contacts are lost at the dimer-dimer interface, whereas dimers (formed by monomers which pair to form two extended β-sheets) appear fairly stable. Overall the simulations provide a detailed view of the dynamics and thermodynamics of wild-type and mutant transthyretins and a rationale of the observed effects.
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29
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Zhang H, Yin C, Jiang Y, van der Spoel D. Force Field Benchmark of Amino Acids: I. Hydration and Diffusion in Different Water Models. J Chem Inf Model 2018; 58:1037-1052. [DOI: 10.1021/acs.jcim.8b00026] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Haiyang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Chunhua Yin
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yang Jiang
- Beijing Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Box 53, Beijing 100029, China
| | - David van der Spoel
- Uppsala Center for Computational Chemistry, Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
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30
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Sala D, Giachetti A, Rosato A. Molecular dynamics simulations of metalloproteins: A folding study of rubredoxin from <em>Pyrococcus furiosus</em>. AIMS BIOPHYSICS 2018. [DOI: 10.3934/biophy.2018.1.77] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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31
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Nawrocki G, Wang PH, Yu I, Sugita Y, Feig M. Slow-Down in Diffusion in Crowded Protein Solutions Correlates with Transient Cluster Formation. J Phys Chem B 2017; 121:11072-11084. [PMID: 29151345 PMCID: PMC5951686 DOI: 10.1021/acs.jpcb.7b08785] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
For a long time, the effect of a crowded cellular environment on protein dynamics has been largely ignored. Recent experiments indicate that proteins diffuse more slowly in a living cell than in a diluted solution, and further studies suggest that the diffusion depends on the local surroundings. Here, detailed insight into how diffusion depends on protein-protein contacts is presented based on extensive all-atom molecular dynamics simulations of concentrated villin headpiece solutions. After force field adjustments in the form of increased protein-water interactions to reproduce experimental data, translational and rotational diffusion was analyzed in detail. Although internal protein dynamics remained largely unaltered, rotational diffusion was found to slow down more significantly than translational diffusion as the protein concentration increased. The decrease in diffusion is interpreted in terms of a transient formation of protein clusters. These clusters persist on sub-microsecond time scales and follow distributions that increasingly shift toward larger cluster size with increasing protein concentrations. Weighting diffusion coefficients estimated for different clusters extracted from the simulations with the distribution of clusters largely reproduces the overall observed diffusion rates, suggesting that transient cluster formation is a primary cause for a slow-down in diffusion upon crowding with other proteins.
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Affiliation(s)
- Grzegorz Nawrocki
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States
| | - Po-hung Wang
- RIKEN Theoretical Molecular Science Laboratory, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Isseki Yu
- RIKEN Theoretical Molecular Science Laboratory, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN iTHES, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Yuji Sugita
- RIKEN Theoretical Molecular Science Laboratory, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN iTHES, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- RIKEN Quantitative Biology Center, Integrated Innovation Building 7F, 6-7-1 Minaotojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
- RIKEN Advanced Institute for Computational Science, 7-1-26 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States
- RIKEN Quantitative Biology Center, Integrated Innovation Building 7F, 6-7-1 Minaotojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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32
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Abriata LA. Structural database resources for biological macromolecules. Brief Bioinform 2017; 18:659-669. [PMID: 27273290 DOI: 10.1093/bib/bbw049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Indexed: 12/30/2022] Open
Abstract
This Briefing reviews the widely used, currently active, up-to-date databases derived from the worldwide Protein Data Bank (PDB) to facilitate browsing, finding and exploring its entries. These databases contain visualization and analysis tools tailored to specific kinds of molecules and interactions, often including also complex metrics precomputed by experts or external programs, and connections to sequence and functional annotation databases. Importantly, updates of most of these databases involves steps of curation and error checks based on specific expertise about the subject molecules or interactions, and removal of sequence redundancy, both leading to better data sets for mining studies compared with the full list of raw PDB entries. The article presents the databases in groups such as those aimed to facilitate browsing through PDB entries, their molecules and their general information, those built to link protein structure with sequence and dynamics, those specific for transmembrane proteins, nucleic acids, interactions of biomacromolecules with each other and with small molecules or metal ions, and those concerning specific structural features or specific protein families. A few webservers directly connected to active databases, and a few databases that have been discontinued but would be important to have back, are also briefly commented on. Along the Briefing, sample cases where these databases have been used to aid structural studies or advance our knowledge about biological macromolecules are referenced. A few specific examples are also given where using these databases is easier and more informative than using raw PDB data.
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Shamsi Z, Moffett AS, Shukla D. Enhanced unbiased sampling of protein dynamics using evolutionary coupling information. Sci Rep 2017; 7:12700. [PMID: 28983093 PMCID: PMC5629199 DOI: 10.1038/s41598-017-12874-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 09/14/2017] [Indexed: 12/25/2022] Open
Abstract
One of the major challenges in atomistic simulations of proteins is efficient sampling of pathways associated with rare conformational transitions. Recent developments in statistical methods for computation of direct evolutionary couplings between amino acids within and across polypeptide chains have allowed for inference of native residue contacts, informing accurate prediction of protein folds and multimeric structures. In this study, we assess the use of distances between evolutionarily coupled residues as natural choices for reaction coordinates which can be incorporated into Markov state model-based adaptive sampling schemes and potentially used to predict not only functional conformations but also pathways of conformational change, protein folding, and protein-protein association. We demonstrate the utility of evolutionary couplings in sampling and predicting activation pathways of the β 2-adrenergic receptor (β 2-AR), folding of the FiP35 WW domain, and dimerization of the E. coli molybdopterin synthase subunits. We find that the time required for β 2-AR activation and folding of the WW domain are greatly diminished using evolutionary couplings-guided adaptive sampling. Additionally, we were able to identify putative molybdopterin synthase association pathways and near-crystal structure complexes from protein-protein association simulations.
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Affiliation(s)
- Zahra Shamsi
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL, 61801, USA
| | - Alexander S Moffett
- Center for Biophysics and Quantitative Biology, University of Illinois, Urbana, IL, 61801, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL, 61801, USA.
- Center for Biophysics and Quantitative Biology, University of Illinois, Urbana, IL, 61801, USA.
- Department of Plant Biology, University of Illinois, Urbana, IL, 61801, USA.
- National Center for Supercomputing Applications, University of Illinois, Urbana, IL, 61801, USA.
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34
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Schmalhorst PS, Deluweit F, Scherrers R, Heisenberg CP, Sikora M. Overcoming the Limitations of the MARTINI Force Field in Simulations of Polysaccharides. J Chem Theory Comput 2017; 13:5039-5053. [DOI: 10.1021/acs.jctc.7b00374] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Felix Deluweit
- Wyatt Technology Europe, Hochstraße
18, 56307 Dernbach, Germany
| | - Roger Scherrers
- Wyatt Technology Europe, Hochstraße
18, 56307 Dernbach, Germany
| | | | - Mateusz Sikora
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
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35
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Feig M, Yu I, Wang PH, Nawrocki G, Sugita Y. Crowding in Cellular Environments at an Atomistic Level from Computer Simulations. J Phys Chem B 2017; 121:8009-8025. [PMID: 28666087 PMCID: PMC5582368 DOI: 10.1021/acs.jpcb.7b03570] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
![]()
The
effects of crowding in biological environments on biomolecular
structure, dynamics, and function remain not well understood. Computer
simulations of atomistic models of concentrated peptide and protein
systems at different levels of complexity are beginning to provide
new insights. Crowding, weak interactions with other macromolecules
and metabolites, and altered solvent properties within cellular environments
appear to remodel the energy landscape of peptides and proteins in
significant ways including the possibility of native state destabilization.
Crowding is also seen to affect dynamic properties, both conformational
dynamics and diffusional properties of macromolecules. Recent simulations
that address these questions are reviewed here and discussed in the
context of relevant experiments.
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Affiliation(s)
- Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan, United States.,Quantitative Biology Center, RIKEN , Kobe, Japan
| | - Isseki Yu
- Theoretical Molecular Science Laboratory, RIKEN , Wako, Japan.,iTHES Research Group, RIKEN , Wako, Japan
| | - Po-Hung Wang
- Theoretical Molecular Science Laboratory, RIKEN , Wako, Japan
| | - Grzegorz Nawrocki
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan, United States
| | - Yuji Sugita
- Quantitative Biology Center, RIKEN , Kobe, Japan.,Theoretical Molecular Science Laboratory, RIKEN , Wako, Japan.,iTHES Research Group, RIKEN , Wako, Japan.,Advanced Institute for Computational Science, RIKEN , Kobe, Japan
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36
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Abriata LA, Spiga E, Peraro MD. Molecular Effects of Concentrated Solutes on Protein Hydration, Dynamics, and Electrostatics. Biophys J 2017; 111:743-755. [PMID: 27558718 DOI: 10.1016/j.bpj.2016.07.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/06/2016] [Accepted: 07/05/2016] [Indexed: 12/20/2022] Open
Abstract
Most studies of protein structure and function are performed in dilute conditions, but proteins typically experience high solute concentrations in their physiological scenarios and biotechnological applications. High solute concentrations have well-known effects on coarse protein traits like stability, diffusion, and shape, but likely also perturb other traits through finer effects pertinent at the residue and atomic levels. Here, NMR and molecular dynamics investigations on ubiquitin disclose variable interactions with concentrated solutes that lead to localized perturbations of the protein's surface, hydration, electrostatics, and dynamics, all dependent on solute size and chemical properties. Most strikingly, small polar uncharged molecules are sticky on the protein surface, whereas charged small molecules are not, but the latter still perturb the internal protein electrostatics as they diffuse nearby. Meanwhile, interactions with macromolecular crowders are favored mainly through hydrophobic, but not through polar, surface patches. All the tested small solutes strongly slow down water exchange at the protein surface, whereas macromolecular crowders do not exert such strong perturbation. Finally, molecular dynamics simulations predict that unspecific interactions slow down microsecond- to millisecond-timescale protein dynamics despite having only mild effects on pico- to nanosecond fluctuations as corroborated by NMR. We discuss our results in the light of recent advances in understanding proteins inside living cells, focusing on the physical chemistry of quinary structure and cellular organization, and we reinforce the idea that proteins should be studied in native-like media to achieve a faithful description of their function.
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Affiliation(s)
- Luciano A Abriata
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, Lausanne, Switzerland.
| | - Enrico Spiga
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, Lausanne, Switzerland.
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37
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Wang PH, Yu I, Feig M, Sugita Y. Influence of protein crowder size on hydration structure and dynamics in macromolecular crowding. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.01.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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38
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Emperador A, Orozco M. Discrete Molecular Dynamics Approach to the Study of Disordered and Aggregating Proteins. J Chem Theory Comput 2017; 13:1454-1461. [PMID: 28157327 DOI: 10.1021/acs.jctc.6b01153] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a refinement of the Coarse Grained PACSAB force field for Discrete Molecular Dynamics (DMD) simulations of proteins in aqueous conditions. As the original version, the refined method provides good representation of the structure and dynamics of folded proteins but provides much better representations of a variety of unfolded proteins, including some very large, impossible to analyze by atomistic simulation methods. The PACSAB/DMD method also reproduces accurately aggregation properties, providing good pictures of the structural ensembles of proteins showing a folded core and an intrinsically disordered region. The combination of accuracy and speed makes the method presented here a good alternative for the exploration of unstructured protein systems.
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Affiliation(s)
- Agustí Emperador
- Institute for Research in Biomedicine (IRB) Barcelona, The Barcelona Institute of Science and Technology, Parc Científic de Barcelona , Josep Samitier 1-5, Barcelona 08028, Spain
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB) Barcelona, The Barcelona Institute of Science and Technology, Parc Científic de Barcelona , Josep Samitier 1-5, Barcelona 08028, Spain.,Joint IRB-BSC Program on Computational Biology , Barcelona 08028, Spain.,Departament de Bioquímica i Biomedicina, Facultat de Biología, Universitat de Barcelona , Avgda Diagonal 647, Barcelona 08028, Spain
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39
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Matthes D, Gapsys V, Brennecke JT, de Groot BL. An Atomistic View of Amyloidogenic Self-assembly: Structure and Dynamics of Heterogeneous Conformational States in the Pre-nucleation Phase. Sci Rep 2016; 6:33156. [PMID: 27616019 PMCID: PMC5018807 DOI: 10.1038/srep33156] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/22/2016] [Indexed: 01/01/2023] Open
Abstract
The formation of well-defined filamentous amyloid structures involves a polydisperse collection of oligomeric states for which relatively little is known in terms of structural organization. Here we use extensive, unbiased explicit solvent molecular dynamics (MD) simulations to investigate the structural and dynamical features of oligomeric aggregates formed by a number of highly amyloidogenic peptides at atomistic resolution on the μs time scale. A consensus approach has been adopted to analyse the simulations in multiple force fields, yielding an in-depth characterization of pre-fibrillar oligomers and their global and local structure properties. A collision cross section analysis revealed structurally heterogeneous aggregate ensembles for the individual oligomeric states that lack a single defined quaternary structure during the pre-nucleation phase. To gain insight into the conformational space sampled in early aggregates, we probed their substructure and found emerging β-sheet subunit layers and a multitude of ordered intermolecular β-structure motifs with growing aggregate size. Among those, anti-parallel out-of-register β-strands compatible with toxic β-barrel oligomers were particularly prevalent already in smaller aggregates and formed prior to ordered fibrillar structure elements. Notably, also distinct fibril-like conformations emerged in the oligomeric state and underscore the notion that pre-nucleated oligomers serve as a critical intermediate step on-pathway to fibrils.
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Affiliation(s)
- Dirk Matthes
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Vytautas Gapsys
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Julian T Brennecke
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Bert L de Groot
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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40
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Mereghetti P, Maccari G, Spampinato GLB, Tozzini V. Optimization of Analytical Potentials for Coarse-Grained Biopolymer Models. J Phys Chem B 2016; 120:8571-9. [PMID: 27150459 DOI: 10.1021/acs.jpcb.6b02555] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The increasing trend in the recent literature on coarse grained (CG) models testifies their impact in the study of complex systems. However, the CG model landscape is variegated: even considering a given resolution level, the force fields are very heterogeneous and optimized with very different parametrization procedures. Along the road for standardization of CG models for biopolymers, here we describe a strategy to aid building and optimization of statistics based analytical force fields and its implementation in the software package AsParaGS (Assisted Parameterization platform for coarse Grained modelS). Our method is based on the use and optimization of analytical potentials, optimized by targeting internal variables statistical distributions by means of the combination of different algorithms (i.e., relative entropy driven stochastic exploration of the parameter space and iterative Boltzmann inversion). This allows designing a custom model that endows the force field terms with a physically sound meaning. Furthermore, the level of transferability and accuracy can be tuned through the choice of statistical data set composition. The method-illustrated by means of applications to helical polypeptides-also involves the analysis of two and three variable distributions, and allows handling issues related to the FF term correlations. AsParaGS is interfaced with general-purpose molecular dynamics codes and currently implements the "minimalist" subclass of CG models (i.e., one bead per amino acid, Cα based). Extensions to nucleic acids and different levels of coarse graining are in the course.
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Affiliation(s)
- Paolo Mereghetti
- Center for Nanotechnology and Innovation @NEST, Istituto Italiano di Tecnologia , Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Giuseppe Maccari
- Center for Nanotechnology and Innovation @NEST, Istituto Italiano di Tecnologia , Piazza San Silvestro 12, 56127 Pisa, Italy
| | | | - Valentina Tozzini
- NEST, Istituto Nanoscienze - CNR and Scuola Normale Superiore , Piazza San Silvestro 12, 56127 Pisa, Italy
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41
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Dominguez H. Molecular dynamics simulations to study the solvent influence on protein structure. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.03.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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42
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Carballo-Pacheco M, Strodel B. Advances in the Simulation of Protein Aggregation at the Atomistic Scale. J Phys Chem B 2016; 120:2991-9. [PMID: 26965454 DOI: 10.1021/acs.jpcb.6b00059] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein aggregation into highly structured amyloid fibrils is associated with various diseases including Alzheimer's disease, Parkinson's disease, and type II diabetes. Amyloids can also have normal biological functions and, in the future, could be used as the basis for novel nanoscale materials. However, a full understanding of the physicochemical forces that drive protein aggregation is still lacking. Such understanding is crucial for the development of drugs that can effectively inhibit aberrant amyloid aggregation and for the directed design of functional amyloids. Atomistic simulations can help understand protein aggregation. In particular, atomistic simulations can be used to study the initial formation of toxic oligomers which are hard to characterize experimentally and to understand the difference in aggregation behavior between different amyloidogenic peptides. Here, we review the latest atomistic simulations of protein aggregation, concentrating on amyloidogenic protein fragments, and provide an outlook for the future in this field.
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Affiliation(s)
- Martín Carballo-Pacheco
- Institute of Complex Systems: Structural Biochemistry , Forschungszentrum Jülich, 52425 Jülich, Germany.,AICES Graduate School, RWTH Aachen University , Schinkelstraße 2, 52062 Aachen, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry , Forschungszentrum Jülich, 52425 Jülich, Germany.,Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf , Universitätsstrasse 1, 40225 Düsseldorf, Germany
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43
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Paluch P, Pawlak T, Jeziorna A, Trébosc J, Hou G, Vega AJ, Amoureux JP, Dracinsky M, Polenova T, Potrzebowski MJ. Analysis of local molecular motions of aromatic sidechains in proteins by 2D and 3D fast MAS NMR spectroscopy and quantum mechanical calculations. Phys Chem Chem Phys 2015; 17:28789-801. [PMID: 26451400 PMCID: PMC4890705 DOI: 10.1039/c5cp04475h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We report a new multidimensional magic angle spinning NMR methodology, which provides an accurate and detailed probe of molecular motions occurring on timescales of nano- to microseconds, in sidechains of proteins. The approach is based on a 3D CPVC-RFDR correlation experiment recorded under fast MAS conditions (ν(R) = 62 kHz), where (13)C-(1)H CPVC dipolar lineshapes are recorded in a chemical shift resolved manner. The power of the technique is demonstrated in model tripeptide Tyr-(d)Ala-Phe and two nanocrystalline proteins, GB1 and LC8. We demonstrate that, through numerical simulations of dipolar lineshapes of aromatic sidechains, their detailed dynamic profile, i.e., the motional modes, is obtained. In GB1 and LC8 the results unequivocally indicate that a number of aromatic residues are dynamic, and using quantum mechanical calculations, we correlate the molecular motions of aromatic groups to their local environment in the crystal lattice. The approach presented here is general and can be readily extended to other biological systems.
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Affiliation(s)
- Piotr Paluch
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, Sienkiewicza 112, PL-90-363 Łodz, Poland.
| | - Tomasz Pawlak
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, Sienkiewicza 112, PL-90-363 Łodz, Poland.
| | - Agata Jeziorna
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, Sienkiewicza 112, PL-90-363 Łodz, Poland.
| | - Julien Trébosc
- Unit of Catalysis and Chemistry of Solids (UCCS), CNRS-8181, University Lille North of France, 59652 Villeneuve d'Ascq, France
| | - Guangjin Hou
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA.
| | - Alexander J Vega
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA.
| | - Jean-Paul Amoureux
- Unit of Catalysis and Chemistry of Solids (UCCS), CNRS-8181, University Lille North of France, 59652 Villeneuve d'Ascq, France and Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China
| | - Martin Dracinsky
- Institute of Organic Chemistry and Biochemistry, AS CR, Flemingovo nam. 2, Prague, Czech Republic.
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA.
| | - Marek J Potrzebowski
- Polish Academy of Sciences, Centre of Molecular and Macromolecular Studies, Sienkiewicza 112, PL-90-363 Łodz, Poland.
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44
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Romero-Romero S, Costas M, Rodríguez-Romero A, Fernández-Velasco DA. Reversibility and two state behaviour in the thermal unfolding of oligomeric TIM barrel proteins. Phys Chem Chem Phys 2015. [DOI: 10.1039/c5cp01599e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The reversible thermal unfolding of oligomeric TIM barrels results from a delicate balance of physicochemical properties related to the sequence, the native and unfolded states and the transition between them.
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Affiliation(s)
- Sergio Romero-Romero
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas
- Departamento de Bioquímica
- Facultad de Medicina
- Universidad Nacional Autónoma de México
- 04510 Ciudad de México
| | - Miguel Costas
- Laboratorio de Biofisicoquímica
- Departamento de Fisicoquímica
- Facultad de Química
- Universidad Nacional Autónoma de México
- 04510 Ciudad de México
| | - Adela Rodríguez-Romero
- Laboratorio de Química de Biomacromoléculas 3
- Departamento de Química de Biomacromoléculas
- Instituto de Química
- Universidad Nacional Autónoma de México
- 04510 Ciudad de México
| | - D. Alejandro Fernández-Velasco
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas
- Departamento de Bioquímica
- Facultad de Medicina
- Universidad Nacional Autónoma de México
- 04510 Ciudad de México
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