1
|
Zhao X, Liao C, Ma YT, Ferrell JB, Schneebeli ST, Li J. Top-down Multiscale Approach To Simulate Peptide Self-Assembly from Monomers. J Chem Theory Comput 2019; 15:1514-1522. [PMID: 30677300 DOI: 10.1021/acs.jctc.8b01025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Modeling peptide assembly from monomers on large time and length scales is often intractable at the atomistic resolution. To address this challenge, we present a new approach which integrates coarse-grained (CG), mixed-resolution, and all-atom (AA) modeling in a single simulation. We simulate the initial encounter stage with the CG model, while the further assembly and reorganization stages are simulated with the mixed-resolution and AA models. We have implemented this top-down approach with new tools to automate model transformations and to monitor oligomer formations. Further, a theory was developed to estimate the optimal simulation length for each stage using a model peptide, melittin. The assembly level, the oligomer distribution, and the secondary structures of melittin simulated by the optimal protocol show good agreement with prior experiments and AA simulations. Finally, our approach and theory have been successfully validated with three amyloid peptides (β-amyloid 16-22, GNNQQNY fragment from the yeast prion protein SUP35, and α-synuclein fibril 35-55), which highlight the synergy from modeling at multiple resolutions. This work not only serves as proof of concept for multiresolution simulation studies but also presents practical guidelines for further self-assembly simulations at more physically and chemically relevant scales.
Collapse
Affiliation(s)
- Xiaochuan Zhao
- Department of Chemistry , The University of Vermont , Burlington , Vermont 05405 , United States
| | - Chenyi Liao
- Department of Chemistry , The University of Vermont , Burlington , Vermont 05405 , United States
| | - Yong-Tao Ma
- Department of Chemistry , The University of Vermont , Burlington , Vermont 05405 , United States
| | - Jonathon B Ferrell
- Department of Chemistry , The University of Vermont , Burlington , Vermont 05405 , United States
| | - Severin T Schneebeli
- Department of Chemistry , The University of Vermont , Burlington , Vermont 05405 , United States
| | - Jianing Li
- Department of Chemistry , The University of Vermont , Burlington , Vermont 05405 , United States
| |
Collapse
|
2
|
Xiao L, Luo R. Exploring a multi-scale method for molecular simulation in continuum solvent model: Explicit simulation of continuum solvent as an incompressible fluid. J Chem Phys 2018; 147:214112. [PMID: 29221408 DOI: 10.1063/1.5016052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We explored a multi-scale algorithm for the Poisson-Boltzmann continuum solvent model for more robust simulations of biomolecules. In this method, the continuum solvent/solute interface is explicitly simulated with a numerical fluid dynamics procedure, which is tightly coupled to the solute molecular dynamics simulation. There are multiple benefits to adopt such a strategy as presented below. At this stage of the development, only nonelectrostatic interactions, i.e., van der Waals and hydrophobic interactions, are included in the algorithm to assess the quality of the solvent-solute interface generated by the new method. Nevertheless, numerical challenges exist in accurately interpolating the highly nonlinear van der Waals term when solving the finite-difference fluid dynamics equations. We were able to bypass the challenge rigorously by merging the van der Waals potential and pressure together when solving the fluid dynamics equations and by considering its contribution in the free-boundary condition analytically. The multi-scale simulation method was first validated by reproducing the solute-solvent interface of a single atom with analytical solution. Next, we performed the relaxation simulation of a restrained symmetrical monomer and observed a symmetrical solvent interface at equilibrium with detailed surface features resembling those found on the solvent excluded surface. Four typical small molecular complexes were then tested, both volume and force balancing analyses showing that these simple complexes can reach equilibrium within the simulation time window. Finally, we studied the quality of the multi-scale solute-solvent interfaces for the four tested dimer complexes and found that they agree well with the boundaries as sampled in the explicit water simulations.
Collapse
Affiliation(s)
- Li Xiao
- Departments of Biomedical Engineering, University of California, Irvine, California 92697, USA
| | - Ray Luo
- Departments of Biomedical Engineering, University of California, Irvine, California 92697, USA
| |
Collapse
|
3
|
Xiao L, Diao J, Greene D, Wang J, Luo R. A Continuum Poisson-Boltzmann Model for Membrane Channel Proteins. J Chem Theory Comput 2017; 13:3398-3412. [PMID: 28564540 PMCID: PMC5728381 DOI: 10.1021/acs.jctc.7b00382] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Membrane proteins constitute a large portion of the human proteome and perform a variety of important functions as membrane receptors, transport proteins, enzymes, signaling proteins, and more. Computational studies of membrane proteins are usually much more complicated than those of globular proteins. Here, we propose a new continuum model for Poisson-Boltzmann calculations of membrane channel proteins. Major improvements over the existing continuum slab model are as follows: (1) The location and thickness of the slab model are fine-tuned based on explicit-solvent MD simulations. (2) The highly different accessibilities in the membrane and water regions are addressed with a two-step, two-probe grid-labeling procedure. (3) The water pores/channels are automatically identified. The new continuum membrane model is optimized (by adjusting the membrane probe, as well as the slab thickness and center) to best reproduce the distributions of buried water molecules in the membrane region as sampled in explicit water simulations. Our optimization also shows that the widely adopted water probe of 1.4 Å for globular proteins is a very reasonable default value for membrane protein simulations. It gives the best compromise in reproducing the explicit water distributions in membrane channel proteins, at least in the water accessible pore/channel regions. Finally, we validate the new membrane model by carrying out binding affinity calculations for a potassium channel, and we observe good agreement with the experimental results.
Collapse
Affiliation(s)
| | | | | | - Junmei Wang
- Department of Pharmaceutical Sciences, University of Pittsburgh , Pittsburgh, Pennsylvania 15261, United States
| | | |
Collapse
|
4
|
Lei J, Qi R, Xie L, Xi W, Wei G. Inhibitory effect of hydrophobic fullerenes on the β-sheet-rich oligomers of a hydrophilic GNNQQNY peptide revealed by atomistic simulations. RSC Adv 2017. [DOI: 10.1039/c6ra27608c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Fullerenes suppress fibril-like β-sheet oligomers by interacting strongly with the nonpolar aliphatic groups of polar residues of GNNQQNY peptide, thus inhibit peptide aggregation.
Collapse
Affiliation(s)
- Jiangtao Lei
- State Key Laboratory of Surface Physics
- Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Department of Physics
- Fudan University
- Shanghai
| | - Ruxi Qi
- State Key Laboratory of Surface Physics
- Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Department of Physics
- Fudan University
- Shanghai
| | - Luogang Xie
- State Key Laboratory of Surface Physics
- Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Department of Physics
- Fudan University
- Shanghai
| | - Wenhui Xi
- State Key Laboratory of Surface Physics
- Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Department of Physics
- Fudan University
- Shanghai
| | - Guanghong Wei
- State Key Laboratory of Surface Physics
- Key Laboratory for Computational Physical Sciences (Ministry of Education)
- Department of Physics
- Fudan University
- Shanghai
| |
Collapse
|
5
|
Ranganathan S, Ghosh D, Maji SK, Padinhateeri R. A minimal conformational switching-dependent model for amyloid self-assembly. Sci Rep 2016; 6:21103. [PMID: 26883720 PMCID: PMC4756677 DOI: 10.1038/srep21103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/19/2016] [Indexed: 11/14/2022] Open
Abstract
Amyloid formation is associated with various pathophysiological conditions like Alzheimer’s and Parkinson’s diseases as well as many useful functions. The hallmark of amyloid assemblies is a conformational transition of the constituent proteins into a β - sheet rich filament. Accounting for this conformational transition in amyloidogenic proteins, we develop an analytically solvable model that can probe the dynamics of an ensemble of single filaments. Using the theory and Monte Carlo simulations, we show the presence of two kinetic regimes for the growth of a self-assembling filament – switching-dependent and –independent growth regimes. We observe a saturation in fibril elongation velocities at higher concentrations in the first regime, providing a novel explanation to the concentration-independence of growth velocities observed experimentally. We also compute the length fluctuation of the filaments to characterize aggregate heterogeneity. From the early velocities and length fluctuation, we propose a novel way of estimating the conformational switching rate. Our theory predicts a kinetic phase diagram that has three distinct phases – short oligomers/monomers, disordered aggregates and β -rich filaments. The model also predicts the force generation potential and the intermittent growth of amyloid fibrils evident from single molecular experiments. Our model could contribute significantly to the physical understanding of amyloid aggregation.
Collapse
Affiliation(s)
| | - Dhiman Ghosh
- Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, India
| | - Samir K Maji
- Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, India
| | | |
Collapse
|
6
|
Nochebuena J, Ireta J. On cooperative effects and aggregation of GNNQQNY and NNQQNY peptides. J Chem Phys 2015; 143:135103. [DOI: 10.1063/1.4932083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Jorge Nochebuena
- Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, A.P. 55-534, México D.F. 09340, Mexico
| | - Joel Ireta
- Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, A.P. 55-534, México D.F. 09340, Mexico
| |
Collapse
|
7
|
Srivastava A, Balaji PV. Interplay of sequence, topology and termini charge in determining the stability of the aggregates of GNNQQNY mutants: a molecular dynamics study. PLoS One 2014; 9:e96660. [PMID: 24817093 PMCID: PMC4015988 DOI: 10.1371/journal.pone.0096660] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 04/11/2014] [Indexed: 01/16/2023] Open
Abstract
This study explores the stabilities of single sheet parallel systems of three sequence variants of 1GNNQQNY7, N2D, N2S and N6D, with variations in aggregate size (5–8) and termini charge (charged or neutral). The aggregates were simulated at 300 and 330 K. These mutations decrease amyloid formation in the yeast prion protein Sup35. The present study finds that these mutations cause instability even in the peptide context. The protonation status of termini is found to be a key determinant of stabilities; other determinants are sequence, position of mutation and aggregate size. All systems with charged termini are unstable, whereas both stable and unstable systems are found when the termini are neutral. When termini are charged, the largest stable aggregate for the N2S and N6D systems has 3 to 4 peptides whereas N2D mutation supports oligomers of larger size (5-and 6-mers) as well. Mutation at 2nd position (N2S and N2D) results in fewer H-bonds at the mutated as well as neighboring (Gly1/Gln4) positions. However, no such effect is found if mutation is at 6th position (N6D). The effect of Asn→Asp mutation depends on the position and termini charge: it is more destabilizing at the 2nd position than at the 6th in case of neutral termini, however, the opposite is true in case of charged termini. Appearance of twist in stable systems and in smaller aggregates formed in unstable systems suggests that twist is integral to amyloid arrangement. Disorder, dissociation or rearrangement of peptides, disintegration or collapse of aggregates and formation of amorphous aggregates observed in these simulations are likely to occur during the early stages of aggregation also. The smaller aggregates formed due to such events have a variety of arrangements of peptides. This suggests polymorphic nature of oligomers and presence of a heterogeneous mixture of oligomers during early stages of aggregation.
Collapse
Affiliation(s)
- Alka Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Petety V. Balaji
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
- * E-mail:
| |
Collapse
|
8
|
Molecular Dynamics Studies on Amyloidogenic Proteins. COMPUTATIONAL METHODS TO STUDY THE STRUCTURE AND DYNAMICS OF BIOMOLECULES AND BIOMOLECULAR PROCESSES 2014. [DOI: 10.1007/978-3-642-28554-7_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
9
|
Ye W, Wang W, Jiang C, Yu Q, Chen H. Molecular dynamics simulations of amyloid fibrils: an in silico approach. Acta Biochim Biophys Sin (Shanghai) 2013; 45:503-8. [PMID: 23532062 DOI: 10.1093/abbs/gmt026] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Amyloid fibrils play causal roles in the pathogenesis of amyloid-related degenerative diseases such as Alzheimer's disease, type II diabetes mellitus, and the prion-related transmissible spongiform encephalopathies. The mechanism of fibril formation and protein aggregation is still hotly debated and remains an important open question in order to develop therapeutic method of these diseases. However, traditional molecular biological and crystallographic experiments could hardly observe atomic details and aggregation process. Molecular dynamics (MD) simulations could provide explanations for experimental results and detailed pathway of protein aggregation. In this review, we focus on the applications of MD simulations on several amyloidogenic protein systems. Furthermore, MD simulations could help us to understand the mechanism of amyloid aggregation and how to design the inhibitors.
Collapse
Affiliation(s)
- Wei Ye
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, College of Life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai 200240, China
| | | | | | | | | |
Collapse
|
10
|
Osborne KL, Bachmann M, Strodel B. Thermodynamic analysis of structural transitions during GNNQQNY aggregation. Proteins 2013; 81:1141-55. [DOI: 10.1002/prot.24263] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/16/2013] [Accepted: 01/17/2013] [Indexed: 01/10/2023]
Affiliation(s)
- Kenneth L. Osborne
- Institute of Complex Systems: Structural Biochemistry; Research Centre Jülich; 52425 Jülich; Germany
| | - Michael Bachmann
- Center for Simulational Physics; The University of Georgia; Athens; Georgia 30602; USA
| | | |
Collapse
|
11
|
Bleiholder C, Dupuis NF, Bowers MT. Dimerization of Chirally Mutated Enkephalin Neurotransmitters: Implications for Peptide and Protein Aggregation Mechanisms. J Phys Chem B 2013; 117:1770-9. [DOI: 10.1021/jp306386p] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Christian Bleiholder
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California
93106, United States
| | - Nicholas F. Dupuis
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California
93106, United States
| | - Michael T. Bowers
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California
93106, United States
| |
Collapse
|
12
|
Wang YJ, Wang JF, Ping J, Yu Y, Wang Y, Lian P, Li X, Li YX, Hao P. Computational studies on the substrate interactions of influenza A virus PB2 subunit. PLoS One 2012; 7:e44079. [PMID: 22957044 PMCID: PMC3434214 DOI: 10.1371/journal.pone.0044079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 07/30/2012] [Indexed: 12/28/2022] Open
Abstract
Influenza virus, which spreads around the world in seasonal epidemics and leads to large numbers of deaths every year, has several ribonucleoproteins in the central core of the viral particle. These viral ribonucleoproteins can specifically bind the conserved 3' and 5' caps of the viral RNAs with responsibility for replication and transcription of the viral RNA in the nucleus of infected cells. A fundamental question of most importance is that how the cap-binding proteins in the influenza virus discriminates between capped RNAs and non-capped ones. To get an answer, we performed molecular dynamics simulations and free energy calculations on the influenza A virus PB2 subunit, an important component of the RNP complexes, with a cap analog m7GTP. Our calculations showed that some key residues in the active site, such as Arg355, His357, Glu361 as well as Gln406, could offer significant hydrogen bonding and hydrophobic interactions with the guanine ring of the cap analog m7GTP to form an aromatic sandwich mechanism for the cap recognition and positioning in the active site. Subsequently, we applied this idea to a virtual screening procedure and identified 5 potential candidates that might be inhibitors against the PB2 subunit. Interestingly, 2 candidates Cpd1 and Cpd2 have been already reported to have inhibitory activities to the influenza virus cap-binding proteins. Further calculation also showed that they had comparatively higher binding affinities to the PB2 subunit than that of m7GTP. We believed that our findings could give an atomic insight into the deeper understanding of the cap recognition and binding mechanism, providing useful information for searching or designing novel drugs against influenza viruses.
Collapse
Affiliation(s)
- Ya-Jun Wang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Jing-Fang Wang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
- Shanghai Center for Bioinformation and Technology, Shanghai, China
| | - Jie Ping
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Yao Yu
- Shanghai Center for Bioinformation and Technology, Shanghai, China
- Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Ying Wang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Peng Lian
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Xuan Li
- Shanghai Center for Bioinformation and Technology, Shanghai, China
- Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yi-Xue Li
- Shanghai Center for Bioinformation and Technology, Shanghai, China
- Bioinformatics Center, Key Laboratory of Systems Biology, Chinese Academy of Sciences, Shanghai, China
| | - Pei Hao
- Shanghai Center for Bioinformation and Technology, Shanghai, China
- Institute of Pasteur, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|
13
|
Srivastava A, Balaji PV. Size, orientation and organization of oligomers that nucleate amyloid fibrils: Clues from MD simulations of pre-formed aggregates. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:963-73. [DOI: 10.1016/j.bbapap.2012.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 04/27/2012] [Accepted: 05/04/2012] [Indexed: 11/30/2022]
|
14
|
Ye W, Chen Y, Wang W, Yu Q, Li Y, Zhang J, Chen HF. Insight into the stability of cross-β amyloid fibril from VEALYL short peptide with molecular dynamics simulation. PLoS One 2012; 7:e36382. [PMID: 22590535 PMCID: PMC3349666 DOI: 10.1371/journal.pone.0036382] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 03/30/2012] [Indexed: 12/13/2022] Open
Abstract
Amyloid fibrils are found in many fatal neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, type II diabetes, and prion disease. The VEALYL short peptide from insulin has been confirmed to aggregate amyloid-like fibrils. However, the aggregation mechanism of amyloid fibril is poorly understood. Here, we utilized molecular dynamics simulation to analyse the stability of VEALYL hexamer. The statistical results indicate that hydrophobic residues play key roles in stabilizing VEALYL hexamer. Single point and two linkage mutants confirmed that Val1, Leu4, and Tyr5 of VEALYL are key residues. The consistency of the results for the VEALYL oligomer suggests that the intermediate states might be trimer (3-0) and pentamer(3-2). These results can help us to obtain an insight into the aggregation mechanism of amyloid fibril. These methods can be used to study the stability of amyloid fibril from other short peptides.
Collapse
Affiliation(s)
- Wei Ye
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, College of Life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Yue Chen
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, College of Life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Wei Wang
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, College of Life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Qingfen Yu
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, College of Life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai, China
| | - Yixue Li
- Shanghai Center for Bioinformation Technology, Shanghai, China
- * E-mail: (HC); (YL); (JZ)
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, School of Medicine, Shanghai Jiaotong University, Shanghai, China
- * E-mail: (HC); (YL); (JZ)
| | - Hai-Feng Chen
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, College of Life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai, China
- Shanghai Center for Bioinformation Technology, Shanghai, China
- * E-mail: (HC); (YL); (JZ)
| |
Collapse
|
15
|
Lewandowski JR, van der Wel PC, Rigney M, Grigorieff N, Griffin RG. Structural complexity of a composite amyloid fibril. J Am Chem Soc 2011; 133:14686-98. [PMID: 21766841 PMCID: PMC3190136 DOI: 10.1021/ja203736z] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The molecular structure of amyloid fibrils and the mechanism of their formation are of substantial medical and biological importance, but present an ongoing experimental and computational challenge. An early high-resolution view of amyloid-like structure was obtained on amyloid-like crystals of a small fragment of the yeast prion protein Sup35p: the peptide GNNQQNY. As GNNQQNY also forms amyloid-like fibrils under similar conditions, it has been theorized that the crystal's structural features are shared by the fibrils. Here we apply magic-angle-spinning (MAS) NMR to examine the structure and dynamics of these fibrils. Previously multiple NMR signals were observed for such samples, seemingly consistent with the presence of polymorphic fibrils. Here we demonstrate that peptides with these three distinct conformations instead assemble together into composite protofilaments. Electron microscopy (EM) of the ribbon-like fibrils indicates that these protofilaments combine in differing ways to form striations of variable widths, presenting another level of structural complexity. Structural and dynamic NMR data reveal the presence of highly restricted side-chain conformations involved in interfaces between differently structured peptides, likely comprising interdigitated steric zippers. We outline molecular interfaces that are consistent with the observed EM and NMR data. The rigid and uniform structure of the GNNQQNY crystals is found to contrast distinctly with the more complex structural and dynamic nature of these "composite" amyloid fibrils. These results provide insight into the fibril-crystal distinction and also indicate a necessary caution with respect to the extrapolation of crystal structures to the study of fibril structure and formation.
Collapse
Affiliation(s)
- Józef R. Lewandowski
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Patrick C.A. van der Wel
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Mike Rigney
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02464, USA
| | - Nikolaus Grigorieff
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02464, USA
| | - Robert G. Griffin
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| |
Collapse
|
16
|
Unique example of amyloid aggregates stabilized by main chain H-bond instead of the steric zipper: molecular dynamics study of the amyloidogenic segment of amylin wild-type and mutants. J Mol Model 2011; 18:891-903. [PMID: 21625904 DOI: 10.1007/s00894-011-1030-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 03/06/2011] [Indexed: 12/19/2022]
Abstract
Most proteins do not aggregate while in their native functional states. However, they may be disturbed from their native conformation by certain change in the environment, and form unwanted oligomeric or polymeric aggregates. Recent experimental data demonstrate that soluble oligomers of amyloidogenic proteins are responsible for amyloidosis and its cytotoxicity. Human islet amyloid polypeptide (IAPP or amylin) is a 37-residue hormone found as fibrillar deposits in pancreatic extracts of nearly all type II diabetics. In this study we performed in silico mutation analysis to examine the stability of the double layer five strand aggregates formed by heptapeptide NNFGAIL segment from amyline peptide. This segment is one of the shortest fragments that can form amyloid fibrils similar to those formed by the full length peptide. The mutants obtained by single glycine replacement were also studied to investigate the specificity of the dry self-complementary interface between the neighboring β-sheet layers. The molecular dynamics simulations of the aggregates run for 20 ns at 330 K, the degree of the aggregate disassembly was investigated using several geometry analysis tools: the root mean square deviations of the C(α) atoms, root mean square fluctuations per residue, twist angles, interstrand distances, fraction of the secondary structure elements, and number of H-bonds. The analysis shows that most mutations make the aggregates unstable, and their stabilities were dependent to a large extent on the position of replaced residues. Our mutational simulations are in agreement with the pervious experimental observations. We also used free binding energy calculations to determine the role of different components: nonpolar effects, electrostatics and entropy in binding. Nonpolar effects remained consistently more favorable in wild type and mutants reinforcing the importance of hydrophobic effects in protein-protein binding. While entropy systematically opposed binding in all cases, there was no clear trend in the entropy difference between wildtype and glycine mutants. Free energy decomposition shows residues situated at the interface were found to make favorable contributions to the peptide-peptide association. The study of the wild type and mutants in an explicit solvent could provide valuable insight into the future computer guided design efforts for the amyloid aggregation inhibitor.
Collapse
|
17
|
Nasica-Labouze J, Meli M, Derreumaux P, Colombo G, Mousseau N. A multiscale approach to characterize the early aggregation steps of the amyloid-forming peptide GNNQQNY from the yeast prion sup-35. PLoS Comput Biol 2011; 7:e1002051. [PMID: 21625573 PMCID: PMC3098217 DOI: 10.1371/journal.pcbi.1002051] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 03/28/2011] [Indexed: 12/17/2022] Open
Abstract
The self-organization of peptides into amyloidogenic oligomers is one of the key events for a wide range of molecular and degenerative diseases. Atomic-resolution characterization of the mechanisms responsible for the aggregation process and the resulting structures is thus a necessary step to improve our understanding of the determinants of these pathologies. To address this issue, we combine the accelerated sampling properties of replica exchange molecular dynamics simulations based on the OPEP coarse-grained potential with the atomic resolution description of interactions provided by all-atom MD simulations, and investigate the oligomerization process of the GNNQQNY for three system sizes: 3-mers, 12-mers and 20-mers. Results for our integrated simulations show a rich variety of structural arrangements for aggregates of all sizes. Elongated fibril-like structures can form transiently in the 20-mer case, but they are not stable and easily interconvert in more globular and disordered forms. Our extensive characterization of the intermediate structures and their physico-chemical determinants points to a high degree of polymorphism for the GNNQQNY sequence that can be reflected at the macroscopic scale. Detailed mechanisms and structures that underlie amyloid aggregation are also provided. The formation of amyloid fibrils is associated with many neurodegenerative diseases such as Alzheimer's, Creutzfeld-Jakob, Parkinson's, the Prion disease and diabetes mellitus. In all cases, proteins misfold to form highly ordered insoluble aggregates called amyloid fibrils that deposit intra- and extracellularly and are resistant to proteases. All proteins are believed to have the instrinsic capability of forming amyloid fibrils that share common specific structural properties that have been observed by X-ray crystallography and by NMR. However, little is known about the aggregation dynamics of amyloid assemblies, and their toxicity mechanism is therefore poorly understood. It is believed that small amyloid oligomers, formed on the aggregation pathway of full amyloid fibrils, are the toxic species. A detailed atomic characterization of the oligomerization process is thus necessary to further our understanding of the amyloid oligomer's toxicity. Our approach here is to study the aggregation dynamics of a 7-residue amyloid peptide GNNQQNY through a combination of numerical techniques. Our results suggest that this amyloid sequence can form fibril-like structures and is polymorphic, which agrees with recent experimental observations. The ability to fully characterize and describe the aggregation pathway of amyloid sequences numerically is key to the development of future drugs to target amyloid oligomers.
Collapse
Affiliation(s)
| | - Massimiliano Meli
- Istituto di Chimica del Riconoscimento Molecolare, CNR, Milano, Italy
| | - Philippe Derreumaux
- Laboratoire de Biochimie Théorique, UPR9080 CNRS, Institut de Biologie Physico-Chimique, Université Paris 7, and Institut Universitaire de France, Paris, France
| | - Giorgio Colombo
- Istituto di Chimica del Riconoscimento Molecolare, CNR, Milano, Italy
- * E-mail: (GC); (NM)
| | - Normand Mousseau
- Département de Physique and GEPROM, Université de Montréal, Montréal, Québec, Canada
- * E-mail: (GC); (NM)
| |
Collapse
|
18
|
Prokhorov VV, Klinov DV, Chinarev AA, Tuzikov AB, Gorokhova IV, Bovin NV. High-resolution atomic force microscopy study of hexaglycylamide epitaxial structures on graphite. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5879-5890. [PMID: 21351798 DOI: 10.1021/la103051w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Two types of hexaglycylamide (HGA) epitaxial lamellar structures coexisting on the surface of highly oriented pyrolytic graphite (HOPG) exposed to water solutions were studied by high-resolution atomic force microscopy (AFM). Lamellae are distinguished by growth direction and by morphology. The lamellae of the first type (L1) produced by depositions from more dilute solutions are close-packed with a period of ∼5.2 nm, twice the HGA molecular length, and form highly ordered domains morphologically similar to the lamellar domains of alkanes. The less-ordered lamellae of the second type (L2) appear at intermediate and large HGA concentrations and demonstrate variable lamellar width, morphological diversity, and a tendency to merge. The interlamellar separation in the domains of close-packed L2 lamellae varies with the discrete increment ∼2.5 nm; the most frequently observed value is ∼7.5-8.0 nm corresponding to the triple HGA molecular length. The growth directions of lamellae of each type have sixfold rotational symmetry indicating epitaxy with graphite; however, the rosettes of L1 and L2 lamellae orientations are misaligned by 30°. The molecular modeling of possible HGA epitaxial packing arrangements on graphite and their classification have been conducted, and the energetically preferable structures are selected. On this basis, the structural models of the L1 and L2 lamellae are proposed explaining the experimentally observed peculiarities as follows: (1) the L1 and L2 lamellae are respectively parallel and antiparallel β-sheets with two HGA molecules in the unit cell oriented normally to the lamellae boundaries, (2) HGA molecules in L1 and L2 lamellae have different orientations with respect to the graphite lattice, respectively along the directions <1120> and <1010>, (3) L1 lamella is the assembly of two hydrogen-bonded parallel β-sheets oriented head-to-head, (4) L2 lamellae are assemblies of several molecular rows (antiparallel β-sheets) cross-linked by hydrogen bonds. The AFM observations indicate that the covering of the hydrophobic graphite by the dense, closely packed, well-ordered monolayers of hydrophilic oligopeptide is possible.
Collapse
Affiliation(s)
- V V Prokhorov
- M. M. Shemyakin & Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Miklukho-Maklaya str., 16/10, 117997 GSP Moscow V-437, Russia.
| | | | | | | | | | | |
Collapse
|
19
|
Cao Z, Liu L, Wang J. Effects of pH and Temperature on the Structural and Thermodynamic Character of a-syn12 Peptide in Aqueous Solution. J Biomol Struct Dyn 2010; 28:343-53. [DOI: 10.1080/07391102.2010.10507364] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
20
|
van der Wel PC, Lewandowski JR, Griffin RG. Structural characterization of GNNQQNY amyloid fibrils by magic angle spinning NMR. Biochemistry 2010; 49:9457-69. [PMID: 20695483 PMCID: PMC3026921 DOI: 10.1021/bi100077x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Several human diseases are associated with the formation of amyloid aggregates, but experimental characterization of these amyloid fibrils and their oligomeric precursors has remained challenging. Experimental and computational analysis of simpler model systems has therefore been necessary, for instance, on the peptide fragment GNNQQNY7−13 of yeast prion protein Sup35p. Expanding on a previous publication, we report here a detailed structural characterization of GNNQQNY fibrils using magic angle spinning (MAS) NMR. On the basis of additional chemical shift assignments we confirm the coexistence of three distinct peptide conformations within the fibrillar samples, as reflected in substantial chemical shift differences. Backbone torsion angle measurements indicate that the basic structure of these coexisting conformers is an extended β-sheet. We structurally characterize a previously identified localized distortion of the β-strand backbone specific to one of the conformers. Intermolecular contacts are consistent with each of the conformers being present in its own parallel and in-register sheet. Overall the MAS NMR data indicate a substantial difference between the structure of the fibrillar and crystalline forms of these peptides, with a clearly increased complexity in the GNNQQNY fibril structure. These experimental data can provide guidance for future work, both experimental and theoretical, and provide insights into the distinction between fibril growth and crystal formation.
Collapse
Affiliation(s)
| | | | - Robert G. Griffin
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| |
Collapse
|
21
|
Berhanu WM, Masunov AE. Natural polyphenols as inhibitors of amyloid aggregation. Molecular dynamics study of GNNQQNY heptapeptide decamer. Biophys Chem 2010; 149:12-21. [DOI: 10.1016/j.bpc.2010.03.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 02/25/2010] [Accepted: 03/04/2010] [Indexed: 10/19/2022]
|
22
|
Andrey SB, Chan ML, Power WP. HRMAS 1H NMR conformational study of the resin-bound amyloid-forming peptide GNNQQNY from the yeast prion Sup35. J Phys Chem A 2010; 114:3457-65. [PMID: 20155963 DOI: 10.1021/jp909899w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The conversion of soluble proteins to insoluble amyloid fibrils is associated with numerous human diseases. The peptide GNNQQNY is a short segment of the yeast prion protein Sup35 that previously has been found to form amyloid fibrils in a similar manner to the protein itself. The approach taken in this work was to attach this peptide sequence to an insoluble polymer matrix through solid phase peptide synthesis and give it the internal freedom to fold into its local conformation in an organic solvent. Observation of its monomeric structure, free from the effects of aggregation, entropic solvent effects, and neighboring molecules, was possible by two-dimensional high-resolution magic angle spinning (1)H NMR spectroscopy. Analysis of the through-bond correlations and through-space interactions observed in the spectra, combined with global energy minimization via computational studies, led to the observation that the peptide chain adopts a compact beta-like turn at the central hydrophilic residues. The technique of peptide attachment to a polymer resin and observation by NMR may allow for future study of single peptide fragments prone to aggregation.
Collapse
Affiliation(s)
- Samuel B Andrey
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | | | | |
Collapse
|
23
|
Vitagliano L, Stanzione F, De Simone A, Esposito L. Dynamics and stability of amyloid-like steric zipper assemblies with hydrophobic dry interfaces. Biopolymers 2010; 91:1161-71. [PMID: 19280623 DOI: 10.1002/bip.21182] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recent seminal investigations have suggested that the basic structural motif of amyloid fibers may be constituted by a tight association of two facing beta-sheets (steric zipper). Although this model has been derived from crystal structures of small peptide models, several theoretical investigations, essentially focused on steric zipper interface containing large polar and/or aromatic side chains, have confirmed the stability of this motif in a crystal-free context. To analyze the general validity of these findings, we carried out molecular dynamics (MD) simulations on aggregates stabilized by steric zipper interfaces made also of small or hydrophobic residues. In particular, we here characterized assemblies formed by the peptides SSTSAA and VQIVYK, whose structures have been recently solved at high resolution. In contrast to previous results obtained for polar/aromatic aggregates of the same size and with similar interface area, steric zipper assemblies composed of a pair of 10-stranded beta-sheets show high fluctuations and significant distortions in the simulation timescales (40-60 ns). Taking into account the crystal packing, the effect of the addition of an extra sheet to the assemblies was also evaluated. The MD results indicate that this addition does not provide extra-stabilization to the pair of sheet models. Although present data do not preclude the possibility that the steric zipper association identified in the crystal structure is the basic motif of SSTSAA and VQIVYK fibers, our findings highlight the importance of the nature of residues directly involved in the motif. Indeed, polar and aromatic residues that may form intrasheet and intersheet interactions likely provide a strong contribution to the steric zipper motif stability. Along this line, assemblies endowed with hydrophobic residues presumably require larger interfaces. In line with this suggestion, MD analysis of the HET-s(218-289) prion models composed of a similar number of strands shows that the assembly is endowed with a remarkable stability.
Collapse
Affiliation(s)
- Luigi Vitagliano
- Istituto di Biostrutture e Bioimmagini, CNR via Mezzocannone 16, I-80134 Napoli, Italy.
| | | | | | | |
Collapse
|
24
|
Yu X, Wang J, Yang JC, Wang Q, Cheng SZ, Nussinov R, Zheng J. Atomic-scale simulations confirm that soluble beta-sheet-rich peptide self-assemblies provide amyloid mimics presenting similar conformational properties. Biophys J 2010; 98:27-36. [PMID: 20085717 PMCID: PMC2800962 DOI: 10.1016/j.bpj.2009.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 09/20/2009] [Accepted: 10/01/2009] [Indexed: 12/13/2022] Open
Abstract
The peptide self-assembly mimic (PSAM) from the outer surface protein A (OspA) can form highly stable but soluble beta-rich self-assembly-like structures similar to those formed by native amyloid-forming peptides. However, unlike amyloids that predominantly form insoluble aggregates, PSAMs are highly water-soluble. Here, we characterize the conformations of these soluble beta-sheet-rich assemblies. We simulate PSAMs with different-sized beta-sheets in the presence and absence of end-capping proteins using all-atom explicit-solvent molecular dynamics, comparing the structural stability, conformational dynamics, and association force. Structural and free-energy comparisons among beta-sheets with different numbers of layers and sequences indicate that in similarity to amyloids, the intersheet side chain-side chain interactions and hydrogen bonds combined with intrasheet salt bridges are the major driving forces in stabilizing the overall structural organization. A detailed structural analysis shows that in similarity to amyloid fibrils, all wild-type and mutated PSAM structures display twisted and bent beta-sheets to some extent, implying that a twisted and bent beta-sheet is a general motif of beta-rich assemblies. Thus, our studies indicate that soluble beta-sheet-rich peptide self-assemblies can provide good amyloid mimics, and as such confirm on the atomic scale that they are excellent systems for amyloid studies. These results provide further insight into the usefulness of such mimics for nanostructure design.
Collapse
Affiliation(s)
- Xiang Yu
- Department of Chemical and Biomolecular Engineering, University of Akron, Akron, Ohio
| | - Jingdai Wang
- Department of Chemical Engineering, Zhejiang University, Hangzhou, China
| | - Jui-Chen Yang
- Department of Chemical and Biomolecular Engineering, University of Akron, Akron, Ohio
| | - Qiuming Wang
- Department of Chemical and Biomolecular Engineering, University of Akron, Akron, Ohio
| | | | - Ruth Nussinov
- Basic Science Program, SAIC-Frederick Inc., Center for Cancer Research Nanobiology Program, NCI-Frederick, Frederick, Maryland
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Jie Zheng
- Department of Chemical and Biomolecular Engineering, University of Akron, Akron, Ohio
| |
Collapse
|
25
|
A model of amyloid's role in disease based on fibril fracture. Biophys Chem 2009; 145:17-28. [PMID: 19735971 DOI: 10.1016/j.bpc.2009.08.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 08/09/2009] [Accepted: 08/09/2009] [Indexed: 02/04/2023]
Abstract
Although the correlative evidence relating the presence of amyloid fibrils and certain disease states (e.g. Alzheimer's disease and Type 2 Diabetes) is overwhelming, a direct causative role for amyloid has proved harder to establish. Current thinking links a narrow region of the aggregate protein size distribution, the so called 'early aggregate' domain to cellular toxicity. A troubling feature of this theory however is that the nucleated reaction mechanism by which amyloid formation is believed to occur results in a very low number concentration of early aggregates which are rapidly extended to form amyloid fibrils. This situation means that the concentration of early aggregates is very low at the time when they are supposedly at their most toxic. Here we adopt a novel explicit simulation strategy to examine a kinetic regime involving nucleated growth combined with fibril fragmentation under which this situation can be reversed so as to produce a high number concentration of small on-pathway toxic aggregates. Dependent upon the rate of fragmentation, the time scale for generation of toxic early aggregates may be coupled, uncoupled or disassociated from the time scale for the appearance of amyloid fibrils. Furthermore the model presents itself as a biochemical 'switch' transitioning between modes of amyloid induced cell death dependent upon either specific amyloid toxicity or non-specific solid mass induced tissue damage.
Collapse
|
26
|
Langkilde AE, Vestergaard B. Methods for structural characterization of prefibrillar intermediates and amyloid fibrils. FEBS Lett 2009; 583:2600-9. [PMID: 19481541 DOI: 10.1016/j.febslet.2009.05.040] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 05/20/2009] [Accepted: 05/22/2009] [Indexed: 11/15/2022]
Abstract
Protein fibrillation is first and foremost a structural phenomenon. Adequate structural investigation of the central conformational individuals of the fibrillation process is however exceedingly difficult. This is due to the nature of the process, which may be described as a dynamically evolving equilibrium between a large number of structural species. These are furthermore of highly diverging sizes and present in very uneven amounts and timeframes. Different structural methods have different strengths and limitations. These, and in particular recent advances within solution analysis of the undisturbed equilibrium using small angle X-ray scattering, are reviewed here.
Collapse
Affiliation(s)
- Annette Eva Langkilde
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | |
Collapse
|