1
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Jia Y, Fernandez A, Sampath J. PEGylation of Insulin and Lysozyme To Stabilize against Thermal Denaturation: A Molecular Dynamics Simulation Study. J Phys Chem B 2023; 127:6856-6866. [PMID: 37498538 DOI: 10.1021/acs.jpcb.3c01289] [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: 07/28/2023]
Abstract
Biologic drugs or "biologics" (proteins derived from living organisms) are one of the fastest-growing classes of FDA-approved therapeutics. These compounds are often fragile and require conjugation to polymers for stabilization, with many proteins too ephemeral for therapeutic use. During storage or administration, proteins tend to unravel and lose their secondary structure due to changes in solution temperature, pH, and other external stressors. To enhance their lifetime, protein drugs currently in the market are conjugated with polyethylene glycol (PEG), owing to its ability to increase the stability, solubility, and pharmacokinetics of protein drugs. Here, we perform all-atom molecular dynamics simulations to study the unfolding process of egg-white lysozyme and insulin at elevated temperatures. We test the validity of two force fields─CHARMM36 and Amber ff99SB-ILDN─in the unfolding process. By calculating global and local properties, we capture residues that deteriorate first─these are the "weak links" in the proteins. Next, we conjugate both proteins with PEG and find that PEG preserves the native structure of the proteins at elevated temperatures by blocking water molecules from entering the hydrophobic core, thereby causing the secondary structure to stabilize.
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Affiliation(s)
- Yinhao Jia
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Adam Fernandez
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Janani Sampath
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
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2
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Chalapathi D, Kumar A, Behera P, Sathi SN, Swaminathan R, Narayana C. Insights on Aggregation of Hen Egg-White Lysozyme from Raman Spectroscopy and MD Simulations. Molecules 2022; 27:molecules27207122. [PMID: 36296716 PMCID: PMC9609503 DOI: 10.3390/molecules27207122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/07/2022] Open
Abstract
Protein misfolding and aggregation play a significant role in several neurodegenerative diseases. In the present work, the spontaneous aggregation of hen egg-white lysozyme (HEWL) in an alkaline pH 12.2 at an ambient temperature was studied to obtain molecular insights. The time-dependent changes in spectral peaks indicated the formation of β sheets and their effects on the backbone and amino acids during the aggregation process. Introducing iodoacetamide revealed the crucial role of intermolecular disulphide bonds amidst monomers in the aggregation process. These findings were corroborated by Molecular Dynamics (MD) simulations and protein-docking studies. MD simulations helped establish and visualize the unfolding of the proteins when exposed to an alkaline pH. Protein docking revealed a preferential dimer formation between the HEWL monomers at pH 12.2 compared with the neutral pH. The combination of Raman spectroscopy and MD simulations is a powerful tool to study protein aggregation mechanisms.
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Affiliation(s)
- Divya Chalapathi
- Chemistry and Physics of Materials Unit, School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Amrendra Kumar
- Department of Bioscience and Bioengineering, Indian Institute of Technology-Guwahati, North Amingaon, Guwahati 781039, India
| | - Pratik Behera
- Transdisciplinary Biology Program, Rajiv Gandhi Centre for Biotechnology, Thycaud Post, Poojapura, Thiruvananthapuram 695014, India
| | - Shijulal Nelson Sathi
- Transdisciplinary Biology Program, Rajiv Gandhi Centre for Biotechnology, Thycaud Post, Poojapura, Thiruvananthapuram 695014, India
| | - Rajaram Swaminathan
- Department of Bioscience and Bioengineering, Indian Institute of Technology-Guwahati, North Amingaon, Guwahati 781039, India
- Correspondence: (R.S.); or (C.N.); Tel.: +91-471-2347-973 (R.S. & C.N.)
| | - Chandrabhas Narayana
- Chemistry and Physics of Materials Unit, School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
- Correspondence: (R.S.); or (C.N.); Tel.: +91-471-2347-973 (R.S. & C.N.)
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3
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Yin F, Yang L, Hou W, Yuan Y, Yu H. Study of dielectric properties of meta-aramid fibers by molecular dynamics methods using modified OPLSAA force field. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Santra S, Jana M. Influence of Aqueous Arginine Solution on Regulating Conformational Stability and Hydration Properties of the Secondary Structural Segments of a Protein at Elevated Temperatures: A Molecular Dynamics Study. J Phys Chem B 2022; 126:1462-1476. [PMID: 35147426 DOI: 10.1021/acs.jpcb.1c09583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effects of aqueous arginine solution on the conformational stability of the secondary structural segments of a globular protein, ubiquitin, and the structure and dynamics of the surrounding water and arginine were examined by performing atomistic molecular dynamics (MD) simulations. Attempts have been made to identify the osmolytic efficacy of arginine solution, and its influence in guiding the hydration properties of the protein at an elevated temperature of 450 K. The similar properties of the protein in pure water at elevated temperatures were computed and compared. Replica exchange MD simulation was performed to explore the arginine solution's sensitivity in stabilizing the protein conformations for a wide range of temperatures (300-450 K). It was observed that although all the helices and strands of the protein undergo unfolding at elevated temperature in pure water, they exhibited native-like conformational dynamics in the presence of arginine at both ambient and elevated temperatures. We find that the higher free energy barrier between the folded native and unfolded states of the protein primarily arises from the structural transformation of α-helix, relative to the strands. Our study revealed that the water structure around the secondary segments depends on the nature of amino acid compositions of the helices and strands. The reorientation of water dipoles around the helices and strands was found hindered due to the presence of arginine in the solution; such hindrance reduces the possibility of exchange of hydrogen bonds that formed between the secondary segments of protein and water (PW), and as a result, PW hydrogen bonds take longer time to relax than in pure water. On the other hand, the origin of slow relaxation of protein-arginine (PA) hydrogen bonds was identified to be due to the presence of different types of protein-bound arginine molecules, where arginine interacts with the secondary structural segments of the protein through multiple/bifurcated hydrogen bonds. These protein-bound arginine formed different kinds of bridged PA hydrogen bonds between amino acid residues of the same secondary segments or among multiple bonds and helped protein to conserve its native folded form firmly.
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Affiliation(s)
- Santanu Santra
- Molecular Simulation Laboratory, Department of Chemistry, National Institute of Technology, Rourkela 769008, India
| | - Madhurima Jana
- Molecular Simulation Laboratory, Department of Chemistry, National Institute of Technology, Rourkela 769008, India
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5
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Wang X, Bowman J, Tu S, Nykypanchuk D, Kuksenok O, Minko S. Polyethylene Glycol Crowder's Effect on Enzyme Aggregation, Thermal Stability, and Residual Catalytic Activity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:8474-8485. [PMID: 34236863 DOI: 10.1021/acs.langmuir.1c00872] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Protein stability and performance in various natural and artificial systems incorporating many other macromolecules for therapeutic, diagnostic, sensor, and biotechnological applications attract increasing interest with the expansion of these technologies. Here we address the catalytic activity of lysozyme protein (LYZ) in the presence of a polyethylene glycol (PEG) crowder in a broad range of concentrations and temperatures in aqueous solutions of two different molecular mass PEG samples (Mw = 3350 and 10000 g/mol). The phase behavior of PEG-protein solutions is examined by using dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS), while the enzyme denaturing is monitored by using an activity assay (AS) and circular dichroism (CD) spectroscopy. Molecular dynamic (MD) simulations are used to illustrate the effect of PEG concentration on protein stability at high temperatures. The results demonstrate that LYZ residual activity after 1 h incubation at 80 °C is improved from 15% up to 55% with the addition of PEG. The improvement is attributed to two underlying mechanisms. (i) Primarily, the stabilizing effect is due to the suppression of the enzyme aggregation because of the stronger PEG-protein interactions caused by the increased hydrophobicity of PEG and lysozyme at elevated temperatures. (ii) The MD simulations showed that the addition of PEG to some degree stabilizes the secondary structures of the enzyme by delaying unfolding at elevated temperatures. The more pronounced effect is observed with an increase in PEG concentration. This trend is consistent with CD and AS experimental results, where the thermal stability is strengthened with increasing of PEG concentration and molecular mass. The results show that the highest stabilizing effect is approached at the critical overlap concentration of PEG.
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Affiliation(s)
- Xue Wang
- Nanostructured Materials Lab, University of Georgia, Athens, Georgia 30602, United States
| | - Jeremy Bowman
- Nanostructured Materials Lab, University of Georgia, Athens, Georgia 30602, United States
| | - Sidong Tu
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Dmytro Nykypanchuk
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Olga Kuksenok
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Sergiy Minko
- Nanostructured Materials Lab, University of Georgia, Athens, Georgia 30602, United States
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6
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Temperature dependent aggregation mechanism and pathway of lysozyme: By all atom and coarse grained molecular dynamics simulation. J Mol Graph Model 2020; 103:107816. [PMID: 33291026 DOI: 10.1016/j.jmgm.2020.107816] [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: 08/15/2020] [Revised: 11/18/2020] [Accepted: 11/18/2020] [Indexed: 11/21/2022]
Abstract
Aggregation of protein causes various diseases including Alzheimer's disease, Parkinson's disease, and type II diabetes. It was found that aggregation of protein depends on many factors like temperature, pH, salt type, salt concentration, ionic strength, protein concentration, co solutes. Here we have tried to capture the aggregation mechanism and pathway of hen egg white lysozyme using molecular dynamics simulations at two different temperatures; 300 K and 340 K. Along with the all atom simulations to get the atomistic details of aggregation mechanism, we have used coarse grained simulation with MARTINI force field to monitor the aggregation for longer duration. Our results suggest that due to the aggregation, changes in the conformation of lysozyme are more at 340 K than at 300 K. The change in the conformation of the lysozyme at 300 K is mainly due to aggregation where at 340 K change in conformation of lysozyme is due to both aggregation and temperature. Also, a more compact aggregated system is formed at 340 K.
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7
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Monhemi H, Tabaee SS. The effects of mutation and modification on the structure and stability of human lysozyme: A molecular link between carbamylation and atherosclerosis. J Mol Graph Model 2020; 100:107703. [PMID: 32799051 DOI: 10.1016/j.jmgm.2020.107703] [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: 03/23/2020] [Revised: 07/01/2020] [Accepted: 07/18/2020] [Indexed: 01/09/2023]
Abstract
Amino acid mutations in some proteins such as lysozyme lead to genetically disorder variants and adverse pathogenic consequences. Recently, amino acid modifications were known as a risk factor in many related diseases such as uremia and atherosclerosis, showing the importance of these surface-structure changes. Although the structural consequences of the hereditary proteins have been examined extensively, such effects for the protein modifications are known to a lesser extent. One drawback in the examination of protein modifications is hardness in experimental detection of modifications by techniques such as NMR and crystallography. Molecular modeling and simulation can help to understand such phenomena at the molecular levels. It is more rational that the effects of both mutation and modification can be compared in a single protein model. Here, molecular dynamics simulation is used to compare the effects of a disease-related carbamylation modification and an amyloidogenic mutation (D67H) in human lysozyme as a model protein. The results show that the carbamylation adversely effects on the tertiary structure, leading to the similar unfolding pathway to the hereditary amyloidogenic form. The carbamylation leads to the instability of the overall protein conformation, especially on the β-domain, which is a characteristic of hereditary amyloidosis in human lysozymes. The aggregation behaviors of both modified and mutant lysozyme were examined by molecular docking calculations. The results showed that the partially unfolded lysozyme might form tight protein aggregates upon carbamylation similar to the amyloidogenic variant. Both single and all-residues carbamylations impose serious conformational changes to the tertiary structure of lysozyme. It was obtained that carbamylation of lysozyme strongly effects on the stability of N-terminal β-sheet, which can produce a highly unstable conformation. The results of this study not only show the adverse structural consequences of a disease-associated post-translational modification, but it also may be very helpful to understand the molecular basis for many carbamylation-related diseases such as atherosclerosis in ESRD patients. The results show that non-native post-translational modifications may be as structurally important as hereditary mutations.
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Affiliation(s)
- Hassan Monhemi
- Department of Chemistry, University of Neyshabur, Neyshabur, Iran.
| | - Seyedeh Samaneh Tabaee
- Healthy Ageing Research Centre, Neyshabur University of Medical Sciences, Neyshabur, Iran; Faculty of Medicine, Neyshabur University of Medical Sciences, Neyshabur, Iran.
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8
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Singh O, Lee PY, Matysiak S, Bermudez H. Dual mechanism of ionic liquid-induced protein unfolding. Phys Chem Chem Phys 2020; 22:19779-19786. [DOI: 10.1039/d0cp03138k] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ionic liquids (ILs) are gaining attention as protein stabilizers and refolding additives.
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Affiliation(s)
- Onkar Singh
- Department of Polymer Science and Engineering
- University of Massachusetts
- Amherst
- USA
| | - Pei-Yin Lee
- Chemical Physics Program
- Institute for Physical Science and Technology
- University of Maryland
- College Park
- USA
| | - Silvina Matysiak
- Fischell Department of Bioengineering
- University of Maryland
- College Park
- USA
| | - Harry Bermudez
- Department of Polymer Science and Engineering
- University of Massachusetts
- Amherst
- USA
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9
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Duan L, Guo X, Cong Y, Feng G, Li Y, Zhang JZH. Accelerated Molecular Dynamics Simulation for Helical Proteins Folding in Explicit Water. Front Chem 2019; 7:540. [PMID: 31448259 PMCID: PMC6691143 DOI: 10.3389/fchem.2019.00540] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 07/15/2019] [Indexed: 12/26/2022] Open
Abstract
In this study, we examined the folding processes of eight helical proteins (2I9M, TC5B, 1WN8, 1V4Z, 1HO2, 1HLL, 2KFE, and 1YYB) at room temperature using the explicit solvent model under the AMBER14SB force field with the accelerated molecular dynamics (AMD) and traditional molecular dynamics (MD), respectively. We analyzed and compared the simulation results obtained by these two methods based on several aspects, such as root mean square deviation (RMSD), native contacts, cluster analysis, folding snapshots, free energy landscape, and the evolution of the radius of gyration, which showed that these eight proteins were successfully and consistently folded into the corresponding native structures by AMD simulations carried out at room temperature. In addition, the folding occurred in the range of 40~180 ns after starting from the linear structures of the eight proteins at 300 K. By contrast, these stable folding structures were not found when the traditional molecular dynamics (MD) simulation was used. At the same time, the influence of high temperatures (350, 400, and 450 K) is also further investigated. Study found that the simulation efficiency of AMD is higher than that of MD simulations, regardless of the temperature. Of these temperatures, 300 K is the most suitable temperature for protein folding for all systems. To further investigate the efficiency of AMD, another trajectory was simulated for eight proteins with the same linear structure but different random seeds at 300 K. Both AMD trajectories reached the correct folded structures. Our result clearly shows that AMD simulation are a highly efficient and reliable method for the study of protein folding.
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Affiliation(s)
- Lili Duan
- School of Physics and Electronics, Shandong Normal University, Jinan, China
| | - Xiaona Guo
- School of Physics and Electronics, Shandong Normal University, Jinan, China
| | - Yalong Cong
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Guoqiang Feng
- School of Physics and Electronics, Shandong Normal University, Jinan, China
| | - Yuchen Li
- School of Physics and Electronics, Shandong Normal University, Jinan, China
| | - John Z H Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China.,Department of Chemistry, New York University, New York, NY, United States
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10
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Choudhury CK, Tu S, Luzinov I, Minko S, Kuksenok O. Designing Highly Thermostable Lysozyme–Copolymer Conjugates: Focus on Effect of Polymer Concentration. Biomacromolecules 2018. [DOI: 10.1021/acs.biomac.8b00027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Chandan Kumar Choudhury
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Sidong Tu
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Igor Luzinov
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Sergiy Minko
- Nanostructured Materials Laboratory, The University of Georgia, Athens, Georgia 30602, United States
| | - Olga Kuksenok
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
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11
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Weber JK, Kang SG, Zhou R. Rare Dissipative Transitions Punctuate the Initiation of Chemical Denaturation in Proteins. Biophys J 2018; 114:812-821. [PMID: 29490243 DOI: 10.1016/j.bpj.2017.12.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/18/2017] [Accepted: 12/27/2017] [Indexed: 10/17/2022] Open
Abstract
Protein unfolding dynamics are bound by their degree of entropy production, a quantity that relates the amount of heat dissipated by a nonequilibrium process to a system's forward and time-reversed trajectories. We here explore the statistics of heat dissipation that emerge in protein molecules subjected to a chemical denaturant. Coupling large molecular dynamics datasets and Markov state models with the theory of entropy production, we demonstrate that dissipative processes can be rigorously characterized over the course of the urea-induced unfolding of the protein chymotrypsin inhibitor 2. By enumerating full entropy production probability distributions as a function of time, we first illustrate that distinct passive and dissipative regimes are present in the denaturation dynamics. Within the dissipative dynamical region, we next find that chymotrypsin inhibitor 2 is strongly driven into unfolded states in which the protein's hydrophobic core has been penetrated by urea molecules and disintegrated. Detailed analyses reveal that urea's interruption of key hydrophobic contacts between core residues causes many of the protein's native structural features to dissolve.
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Affiliation(s)
- Jeffrey K Weber
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York
| | - Seung-Gu Kang
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York
| | - Ruhong Zhou
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York; Department of Chemistry, Columbia University, New York, New York.
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12
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Zheng T, Yang Z, Gui D, Liu Z, Wang X, Dai X, Liu S, Zhang L, Gao Y, Chen L, Sheng D, Wang Y, Diwu J, Wang J, Zhou R, Chai Z, Albrecht-Schmitt TE, Wang S. Overcoming the crystallization and designability issues in the ultrastable zirconium phosphonate framework system. Nat Commun 2017; 8:15369. [PMID: 28555656 PMCID: PMC5459948 DOI: 10.1038/ncomms15369] [Citation(s) in RCA: 236] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 03/23/2017] [Indexed: 12/22/2022] Open
Abstract
Metal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. Herein, we overcome these challenges and obtain single crystals of three zirconium phosphonates that are suitable for structural analysis. These compounds are built by previously unknown isolated zirconium phosphonate clusters and exhibit combined high porosity and ultrastability even in fuming acids. SZ-2 possesses the largest void volume recorded in zirconium phosphonates and SZ-3 represents the most porous crystalline zirconium phosphonate and the only porous MOF material reported to survive in aqua regia. SZ-2 and SZ-3 can effectively remove uranyl ions from aqueous solutions over a wide pH range, and we have elucidated the removal mechanism. Zirconium phosphonate based metal-organic frameworks often exhibit superior chemical stabilities, but typically exist as poorly crystalline or amorphous materials. Here the authors exploit an ionothermal method to obtain highly porous and remarkably stable single crystalline zirconium phosphonate frameworks that can efficiently remove uranyl ions from aqueous solutions.
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Affiliation(s)
- Tao Zheng
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China.,School of Environment and Biological Engineering, Nanjing University of Science &Technology, Nanjing 210094, China
| | - Zaixing Yang
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Daxiang Gui
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Zhiyong Liu
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Xiangxiang Wang
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Xing Dai
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Shengtang Liu
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Linjuan Zhang
- Shanghai Institute of Applied Physics and Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800, China
| | - Yang Gao
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Lanhua Chen
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Daopeng Sheng
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Yanlong Wang
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Juan Diwu
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Jianqiang Wang
- Shanghai Institute of Applied Physics and Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800, China
| | - Ruhong Zhou
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China.,Computational Biology Center, IBM Thomas J Watson Research Center, Yorktown Heights, New York 10598, USA.,Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Zhifang Chai
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
| | - Thomas E Albrecht-Schmitt
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftain Way, Tallahassee, Florida 32306, USA
| | - Shuao Wang
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Jiangsu 215123, China
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13
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Patel D, Kuyucak S. Computational study of aggregation mechanism in human lysozyme[D67H]. PLoS One 2017; 12:e0176886. [PMID: 28467454 PMCID: PMC5415109 DOI: 10.1371/journal.pone.0176886] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 04/19/2017] [Indexed: 11/18/2022] Open
Abstract
Aggregation of proteins is an undesired phenomena that affects both human health and bioengineered products such as therapeutic proteins. Finding preventative measures could be facilitated by a molecular-level understanding of dimer formation, which is the first step in aggregation. Here we present a molecular dynamics (MD) study of dimer formation propensity in human lysozyme and its D67H variant. Because the latter protein aggregates while the former does not, they offer an ideal system for testing the feasibility of the proposed MD approach which comprises three stages: i) partially unfolded conformers involved in dimer formation are generated via high-temperature MD simulations, ii) potential dimer structures are searched using docking and refined with MD, iii) free energy calculations are performed to find the most stable dimer structure. Our results provide a detailed explanation for how a single mutation (D67H) turns human lysozyme from non-aggregating to an aggregating protein. Conversely, the proposed method can be used to identify the residues causing aggregation in a protein, which can be mutated to prevent it.
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Affiliation(s)
- Dharmeshkumar Patel
- School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Serdar Kuyucak
- School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
- * E-mail:
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14
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Duan L, Zhu T, Ji C, Zhang Q, Zhang JZH. Direct folding simulation of helical proteins using an effective polarizable bond force field. Phys Chem Chem Phys 2017; 19:15273-15284. [DOI: 10.1039/c7cp02101a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Snapshots of the intermediate conformation of Trp-cage at various simulation times using AMBER03, EPB03, AMBER12SB, and EPB12SB. Here, the N terminal is always on the top.
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Affiliation(s)
- Lili Duan
- School of Physics and Electronics
- Shandong Normal University
- Jinan 250014
- China
- School of Chemistry and Molecular Engineering
| | - Tong Zhu
- School of Chemistry and Molecular Engineering
- East China Normal University
- Shanghai 200062
- China
| | - Changge Ji
- School of Chemistry and Molecular Engineering
- East China Normal University
- Shanghai 200062
- China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai
| | - Qinggang Zhang
- School of Physics and Electronics
- Shandong Normal University
- Jinan 250014
- China
| | - John Z. H. Zhang
- School of Chemistry and Molecular Engineering
- East China Normal University
- Shanghai 200062
- China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai
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15
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Tian X, Yang Z, Duan G, Wu A, Gu Z, Zhang L, Chen C, Chai Z, Ge C, Zhou R. Graphene Oxide Nanosheets Retard Cellular Migration via Disruption of Actin Cytoskeleton. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:1602133. [PMID: 27762498 DOI: 10.1002/smll.201602133] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/25/2016] [Indexed: 05/19/2023]
Abstract
Graphene and graphene-based nanomaterials are broadly used for various biomedical applications due to their unique physiochemical properties. However, how graphene-based nanomaterials interact with biological systems has not been thoroughly studied. This study shows that graphene oxide (GO) nanosheets retard A549 lung carcinoma cell migration through nanosheet-mediated disruption of intracellular actin filaments. After GO nanosheets treatment, A549 cells display slower migration and the structure of the intracellular actin filaments is dramatically changed. It is found that GO nanosheets are capable of absorbing large amount of actin and changing the secondary structures of actin monomers. Large-scale all-atom molecular dynamics simulations further reveal the interactions between GO nanosheets and actin filaments at molecular details. GO nanosheets can insert into the interstrand gap of actin tetramer (helical repeating unit of actin filament) and cause the separation of the tetramer which eventually leads to the disruption of actin filaments. These findings offer a novel mechanism of GO nanosheet induced biophysical responses and provide more insights into their potential for biomedical applications.
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Affiliation(s)
- Xin Tian
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
| | - Zaixing Yang
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
| | - Guangxin Duan
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
| | - Anqing Wu
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
| | - Zonglin Gu
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
| | - Leili Zhang
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York, NY, 10598, USA
| | - Chunying Chen
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology and Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Zhifang Chai
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology and Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Cuicui Ge
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
| | - Ruhong Zhou
- School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York, NY, 10598, USA
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
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16
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Du X, Sang P, Xia YL, Li Y, Liang J, Ai SM, Ji XL, Fu YX, Liu SQ. Comparative thermal unfolding study of psychrophilic and mesophilic subtilisin-like serine proteases by molecular dynamics simulations. J Biomol Struct Dyn 2016; 35:1500-1517. [PMID: 27485684 DOI: 10.1080/07391102.2016.1188155] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Molecular dynamics (MD) simulations of a subtilisin-like serine protease VPR from the psychrophilic marine bacterium Vibrio sp. PA-44 and its mesophilic homologue, proteinase K (PRK), have been performed for 20 ns at four different temperatures (300, 373, 473, and 573 K). The comparative analyses of MD trajectories reveal that at almost all temperatures, VPR exhibits greater structural fluctuations/deviations, more unstable regular secondary structural elements, and higher global flexibility than PRK. Although these two proteases follow similar unfolding pathways at high temperatures, VPR initiates unfolding at a lower temperature and unfolds faster at the same high temperatures than PRK. These observations collectively indicate that VPR is less stable and more heat-labile than PRK. Analyses of the structural/geometrical properties reveal that, when compared to PRK, VPR has larger radius of gyration (Rg), less intramolecular contacts and hydrogen bonds (HBs), more protein-solvent HBs, and smaller burial of nonpolar area and larger exposure of polar area. These suggest that the increased flexibility of VPR would be most likely caused by its reduced intramolecular interactions and more favourable protein-solvent interactions arising from the larger exposure of the polar area, whereas the enhanced stability of PRK could be ascribed to its increased intramolecular interactions arising from the better optimized hydrophobicity. The factors responsible for the significant differences in local flexibility between these two proteases were also analyzed and ascertained. This study provides insights into molecular basis of thermostability of homologous serine proteases adapted to different temperatures.
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Affiliation(s)
- Xing Du
- a Laboratory for Conservation and Utilization of Bio-Resources , Yunnan University , Kunming 650091 , PR China
| | - Peng Sang
- b Laboratory of Molecular Cardiology, Department of Cardiology , The First Affiliated Hospital of Kunming Medical University , Kunming 650032 , PR China
| | - Yuan-Ling Xia
- a Laboratory for Conservation and Utilization of Bio-Resources , Yunnan University , Kunming 650091 , PR China
| | - Yi Li
- a Laboratory for Conservation and Utilization of Bio-Resources , Yunnan University , Kunming 650091 , PR China
| | - Jing Liang
- a Laboratory for Conservation and Utilization of Bio-Resources , Yunnan University , Kunming 650091 , PR China
| | - Shi-Meng Ai
- c Department of Applied Mathematics , Yunnan Agricultural University , Kunming 650201 , PR China
| | - Xing-Lai Ji
- a Laboratory for Conservation and Utilization of Bio-Resources , Yunnan University , Kunming 650091 , PR China.,d Key Laboratory for Tumor Molecular Biology of High Education in Yunnan Province, School of Life Sciences , Yunnan University , Kunming 650223 , PR China
| | - Yun-Xin Fu
- a Laboratory for Conservation and Utilization of Bio-Resources , Yunnan University , Kunming 650091 , PR China.,e Human Genetics Center and Division of Biostatistics, School of Public Health , The University of Texas Health Science Center , Houston , TX , 77030 , USA
| | - Shu-Qun Liu
- a Laboratory for Conservation and Utilization of Bio-Resources , Yunnan University , Kunming 650091 , PR China.,d Key Laboratory for Tumor Molecular Biology of High Education in Yunnan Province, School of Life Sciences , Yunnan University , Kunming 650223 , PR China
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17
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Reversible thermal unfolding of a yfdX protein with chaperone-like activity. Sci Rep 2016; 6:29541. [PMID: 27404435 PMCID: PMC4941729 DOI: 10.1038/srep29541] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 06/20/2016] [Indexed: 01/16/2023] Open
Abstract
yfdX proteins are ubiquitously present in a large number of virulent bacteria. A member of this family of protein in E. coli is known to be up-regulated by the multidrug response regulator. Their abundance in such bacteria suggests some important yet unidentified functional role of this protein. Here, we study the thermal response and stability of yfdX protein STY3178 from Salmonella Typhi using circular dichroism, steady state fluorescence, dynamic light scattering and nuclear magnetic resonance experiments. We observe the protein to be stable up to a temperature of 45 °C. It folds back to the native conformation from unfolded state at temperature as high as 80 °C. The kinetic measurements of unfolding and refolding show Arrhenius behavior where the refolding involves less activation energy barrier than that of unfolding. We propose a homology model to understand the stability of the protein. Our molecular dynamic simulation studies on this model structure at high temperature show that the structure of this protein is quite stable. Finally, we report a possible functional role of this protein as a chaperone, capable of preventing DTT induced aggregation of insulin. Our studies will have broader implication in understanding the role of yfdX proteins in bacterial function and virulence.
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18
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Robust Denaturation of Villin Headpiece by MoS2 Nanosheet: Potential Molecular Origin of the Nanotoxicity. Sci Rep 2016; 6:28252. [PMID: 27312409 PMCID: PMC4911589 DOI: 10.1038/srep28252] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 06/02/2016] [Indexed: 12/13/2022] Open
Abstract
MoS2 nanosheet, a new two-dimensional transition metal dichalcogenides nanomaterial, has attracted significant attentions lately due to many potential promising biomedical applications. Meanwhile, there is also a growing concern on its biocompatibility, with little known on its interactions with various biomolecules such as proteins. In this study, we use all-atom molecular dynamics simulations to investigate the interaction of a MoS2 nanosheet with Villin Headpiece (HP35), a model protein widely used in protein folding studies. We find that MoS2 exhibits robust denaturing capability to HP35, with its secondary structures severely destroyed within hundreds of nanosecond simulations. Both aromatic and basic residues are critical for the protein anchoring onto MoS2 surface, which then triggers the successive protein unfolding process. The main driving force behind the adsorption process is the dispersion interaction between protein and MoS2 monolayer. Moreover, water molecules at the interface between some key hydrophobic residues (e.g. Trp-64) and MoS2 surface also help to accelerate the process driven by nanoscale drying, which provides a strong hydrophobic force. These findings might have shed new light on the potential nanotoxicity of MoS2 to proteins with atomic details, which should be helpful in guiding future biomedical applications of MoS2 with its nanotoxicity mitigated.
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19
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Feng M, Kang H, Yang Z, Luan B, Zhou R. Potential disruption of protein-protein interactions by graphene oxide. J Chem Phys 2016; 144:225102. [PMID: 27306022 DOI: 10.1063/1.4953562] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Graphene oxide (GO) is a promising novel nanomaterial with a wide range of potential biomedical applications due to its many intriguing properties. However, very little research has been conducted to study its possible adverse effects on protein-protein interactions (and thus subsequent toxicity to human). Here, the potential cytotoxicity of GO is investigated at molecular level using large-scale, all-atom molecular dynamics simulations to explore the interaction mechanism between a protein dimer and a GO nanosheet oxidized at different levels. Our theoretical results reveal that GO nanosheet could intercalate between the two monomers of HIV-1 integrase dimer, disrupting the protein-protein interactions and eventually lead to dimer disassociation as graphene does [B. Luan et al., ACS Nano 9(1), 663 (2015)], albeit its insertion process is slower when compared with graphene due to the additional steric and attractive interactions. This study helps to better understand the toxicity of GO to cell functions which could shed light on how to improve its biocompatibility and biosafety for its wide potential biomedical applications.
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Affiliation(s)
- Mei Feng
- Department of Physics, Institute of Quantitative Biology, Zhejiang University, Hangzhou 310027, China
| | - Hongsuk Kang
- Computational Biological Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Zaixing Yang
- Institute of Quantitative Biology and Medicine, SRMP and RAD-X, and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
| | - Binquan Luan
- Computational Biological Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Ruhong Zhou
- Department of Physics, Institute of Quantitative Biology, Zhejiang University, Hangzhou 310027, China
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20
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Mohanta D, Jana M. Effect of ethanol concentrations on temperature driven structural changes of chymotrypsin inhibitor 2. J Chem Phys 2016; 144:165101. [DOI: 10.1063/1.4947239] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Dayanidhi Mohanta
- Molecular Simulation Laboratory, Department of Chemistry, National Institute of Technology, Rourkela 769008, India
| | - Madhurima Jana
- Molecular Simulation Laboratory, Department of Chemistry, National Institute of Technology, Rourkela 769008, India
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21
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Arooj M, Gandhi NS, Kreck CA, Arrigan DWM, Mancera RL. Adsorption and Unfolding of Lysozyme at a Polarized Aqueous–Organic Liquid Interface. J Phys Chem B 2016; 120:3100-12. [DOI: 10.1021/acs.jpcb.6b00536] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mahreen Arooj
- School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute
for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University, GPO
Box U1987, Perth, WA 6845, Australia
| | - Neha S. Gandhi
- School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute
for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University, GPO
Box U1987, Perth, WA 6845, Australia
| | - Cara A. Kreck
- School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute
for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University, GPO
Box U1987, Perth, WA 6845, Australia
| | - Damien W. M. Arrigan
- School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute
for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University, GPO
Box U1987, Perth, WA 6845, Australia
| | - Ricardo L. Mancera
- School of Biomedical Sciences, CHIRI Biosciences and Curtin Institute
for Computation, ‡Department of Chemistry and Nanochemistry Research Institute, Curtin University, GPO
Box U1987, Perth, WA 6845, Australia
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22
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Luan B, Huynh T, Zhou R. Potential Interference of Protein-Protein Interactions by Graphyne. J Phys Chem B 2016; 120:2124-31. [PMID: 26885561 DOI: 10.1021/acs.jpcb.5b11449] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Graphyne has attracted tremendous attention recently due to its many potentially superior properties relative to those of graphene. Although extensive efforts have been devoted to explore the applicability of graphyne as an alternative nanomaterial for state-of-the-art nanotechnology (including biomedical applications), knowledge regarding its possible adverse effects to biological cells is still lacking. Here, using large-scale all-atom molecular dynamics simulations, we investigate the potential toxicity of graphyne by interfering a protein-protein interaction (ppI). We found that graphyne could indeed disrupt the ppIs by cutting through the protein-protein interface and separating the protein complex into noncontacting ones, due to graphyne's dispersive and hydrophobic interaction with the hydrophobic residues residing at the dimer interface. Our results help to elucidate the mechanism of interaction between graphyne and ppI networks within a biological cell and provide insights for its hazard reduction.
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Affiliation(s)
- Binquan Luan
- Computational Biological Center, IBM Thomas J. Watson Research, Yorktown Heights, New York 10598, United States.,Department of Physics, Zhejiang University , Hangzhou 310027, China
| | - Tien Huynh
- Computational Biological Center, IBM Thomas J. Watson Research, Yorktown Heights, New York 10598, United States
| | - Ruhong Zhou
- Computational Biological Center, IBM Thomas J. Watson Research, Yorktown Heights, New York 10598, United States.,Department of Physics, Zhejiang University , Hangzhou 310027, China.,Department of Chemistry, Columbia University , New York, New York 10027, United States
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23
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Gu Z, Zhang Y, Luan B, Zhou R. DNA translocation through single-layer boron nitride nanopores. SOFT MATTER 2016; 12:817-23. [PMID: 26537824 DOI: 10.1039/c5sm02197a] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Ultra-thin nanopores have become promising biological sensors because of their outstanding signal-to-noise ratio and spatial resolution. Here, we show that boron nitride (BN), which is a new two-dimensional (2D) material similar to graphene, could be utilized for making a nanopore with an atomic thickness. Using an all-atom molecular dynamics simulation, we investigated the dynamics of DNA translocation through the BN nanopore. The results of our simulations demonstrated that it is possible to detect different double-stranded DNA (dsDNA) sequences from the recording of ionic currents through the pore during the DNA translocation. Surprisingly, opposite to results for a graphene nanopore, we found the calculated blockage current for poly(A-T)40 in a BN nanopore to be less than that for poly(G-C)40. Also in contrast with the case of graphene nanopores, dsDNA models moved smoothly and in an unimpeded manner through the BN nanopores in the simulations, suggesting a potential advantage for using BN nanopores to design stall-free sequencing devices. BN nanopores, which display several properties (such as being hydrophilic and non-metallic) that are superior to those of graphene, are thus expected to find applications in the next generation of high-speed and low-cost biological sensors.
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Affiliation(s)
- Zonglin Gu
- School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China
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24
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Duan G, Kang SG, Tian X, Garate JA, Zhao L, Ge C, Zhou R. Protein corona mitigates the cytotoxicity of graphene oxide by reducing its physical interaction with cell membrane. NANOSCALE 2015; 7:15214-24. [PMID: 26315610 DOI: 10.1039/c5nr01839k] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Many recent studies have shown that the way nanoparticles interact with cells and biological molecules can vary greatly in the serum-containing or serum-free culture medium. However, the underlying molecular mechanisms of how the so-called "protein corona" formed in serum medium affects nanoparticles' biological responses are still largely unresolved. Thus, it is critical to understand how absorbed proteins on the surfaces of nanoparticles alter their biological effects. In this work, we have demonstrated with both experimental and theoretical approaches that protein BSA coating can mitigate the cytotoxicity of graphene oxide (GO) by reducing its cell membrane penetration. Our cell viability and cellular uptake experiments showed that protein corona decreased cellular uptake of GO, thus significantly mitigating the potential cytotoxicity of GO. The electron microscopy images also confirmed that protein corona reduced the cellular morphological damage by limiting GO penetration into the cell membrane. Further molecular dynamics (MD) simulations validated the experimental results and revealed that the adsorbed BSA in effect weakened the interaction between the phospholipids and graphene surface due to a reduction of the available surface area plus an unfavorable steric effect, thus significantly reducing the graphene penetration and lipid bilayer damaging. These findings provide new insights into the underlying molecular mechanism of this important graphene protein corona interaction with cell membranes, and should have implications in future development of graphene-based biomedical applications.
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Affiliation(s)
- Guangxin Duan
- Institute of Quantitative Biology and Medicine, SRMP and RAD-X, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China.
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25
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Glover DJ, Clark DS. Oligomeric assembly is required for chaperone activity of the filamentous γ-prefoldin. FEBS J 2015; 282:2985-97. [DOI: 10.1111/febs.13341] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 05/17/2015] [Accepted: 06/06/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Dominic J. Glover
- Department of Chemical and Biomolecular Engineering; University of California; Berkeley CA USA
| | - Douglas S. Clark
- Department of Chemical and Biomolecular Engineering; University of California; Berkeley CA USA
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26
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An D, Su J, Weber JK, Gao X, Zhou R, Li J. A Peptide-Coated Gold Nanocluster Exhibits Unique Behavior in Protein Activity Inhibition. J Am Chem Soc 2015; 137:8412-8. [DOI: 10.1021/jacs.5b00888] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Deyi An
- CAS Key Lab for
Biomedical Effects of Nanomaterials and Nanosafety, Institute of High
Energy Physics, Chinese Academy of Science, Beijing 100049, PR China
- College of Science, Yanshan University, Qinhuangdao 066004, PR China
| | - Jiguo Su
- College of Science, Yanshan University, Qinhuangdao 066004, PR China
| | - Jeffrey K. Weber
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Xueyun Gao
- CAS Key Lab for
Biomedical Effects of Nanomaterials and Nanosafety, Institute of High
Energy Physics, Chinese Academy of Science, Beijing 100049, PR China
| | - Ruhong Zhou
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
- Institute
of Quantitative Biology and Medicine, SRMP and RAD-X, Soochow University, Suzhou 215123, PR China
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Jingyuan Li
- CAS Key Lab for
Biomedical Effects of Nanomaterials and Nanosafety, Institute of High
Energy Physics, Chinese Academy of Science, Beijing 100049, PR China
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27
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Surface Curvature Relation to Protein Adsorption for Carbon-based Nanomaterials. Sci Rep 2015; 5:10886. [PMID: 26041015 PMCID: PMC4455116 DOI: 10.1038/srep10886] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 04/23/2015] [Indexed: 12/12/2022] Open
Abstract
The adsorption of proteins onto carbon-based nanomaterials (CBNs) is dictated by hydrophobic and π-π interactions between aliphatic and aromatic residues and the conjugated CBN surface. Accordingly, protein adsorption is highly sensitive to topological constraints imposed by CBN surface structure; in particular, adsorption capacity is thought to increase as the incident surface curvature decreases. In this work, we couple Molecular Dynamics (MD) simulations with fluorescence spectroscopy experiments to characterize this curvature dependence in detail for the model protein bovine serum albumin (BSA). By studying BSA adsorption onto carbon nanotubes of increasing radius (featuring descending local curvatures) and a flat graphene sheet, we confirm that adsorption capacity is indeed enhanced on flatter surfaces. Naïve fluorescence experiments featuring multi-walled carbon nanotubes (MWCNTs), however, conform to an opposing trend. To reconcile these observations, we conduct additional MD simulations with MWCNTs that match those prepared in experiments; such simulations indicate that increased mass to surface area ratios in multi-walled systems explain the observed discrepancies. In reduction, our work substantiates the inverse relationship between protein adsorption capacity and surface curvature and further demonstrates the need for subtle consideration in experimental and simulation design.
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28
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The role of basic residues in the adsorption of blood proteins onto the graphene surface. Sci Rep 2015; 5:10873. [PMID: 26034971 PMCID: PMC4451687 DOI: 10.1038/srep10873] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 05/05/2015] [Indexed: 12/12/2022] Open
Abstract
With its many unique properties, graphene has shown great potential in various biomedical applications, while its biocompatibility has also attracted growing concerns. Previous studies have shown that the formation of protein-graphene corona could effectively reduce its cytotoxicity; however, the underlying molecular mechanism remains not well-understood. Herein, we use extensive molecular dynamics simulations to demonstrate that blood proteins such as bovine fibrinogen (BFG) can absorb onto the graphene surface quickly and tightly to form a corona complex. Aromatic residues contributed significantly during this adsorption process due to the strong π−π stacking interactions between their aromatic rings and the graphene sp2-carbons. Somewhat surprisingly, basic residues like arginine, also played an equally or even stronger role during this process. The strong dispersion interactions between the sidechains of these solvent-exposed basic residues and the graphene surface provide the driving force for a tight binding of these basic residues. To the best of our knowledge, this is the first study with blood proteins to show that, in addition to the aromatic residues, the basic residues also play an important role in the formation of protein-graphene corona complexes.
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29
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A theoretical study of the unfolding pathway of reduced Human serum albumin. J Mol Model 2015; 21:106. [DOI: 10.1007/s00894-015-2659-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/16/2015] [Indexed: 12/12/2022]
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30
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Bayram Akcapinar G, Venturini A, Martelli PL, Casadio R, Sezerman UO. Modulating the thermostability of Endoglucanase I from Trichoderma reesei using computational approaches. Protein Eng Des Sel 2015; 28:127-35. [DOI: 10.1093/protein/gzv012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/04/2015] [Indexed: 11/12/2022] Open
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31
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Wang B, Seabrook SA, Nedumpully-Govindan P, Chen P, Yin H, Waddington L, Epa VC, Winkler DA, Kirby JK, Ding F, Ke PC. Thermostability and reversibility of silver nanoparticle-protein binding. Phys Chem Chem Phys 2014; 17:1728-39. [PMID: 25461673 DOI: 10.1039/c4cp04996a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The interactions between nanoparticles (NPs) and proteins in living systems are a precursor to the formation of a NP-protein "corona" that underlies cellular and organism responses to nanomaterials. However, the thermodynamic properties and reversibility of NP-protein interactions have rarely been examined. Using an automated, high-throughput and temperature-controlled dynamic light scattering (DLS) technique we observed a distinct hysteresis in the hydrodynamic radius of branched polyethyleneimine (BPEI) coated-silver nanoparticles (bAgNPs) exposed to like-charged lysozyme during the processes of heating and cooling, in contrast to the irreversible interactions between bAgNPs and oppositely charged alpha lactalbumin (ALact). Our discrete molecular dynamics (DMD) simulations offered a new molecular insight into the differential structure, dynamics and thermodynamics of bAgNPs binding with the two protein homologs and further revealed the different roles of the capping agents of citrate and BPEI in NP-protein interactions. This study facilitates our understanding of the transformation of nanomaterials in living systems, whose implications range from the field study of nanotoxicology to nanomaterials synthesis, nanobiotechnology and nanomedicine.
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Affiliation(s)
- Bo Wang
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA
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32
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Bio-mimicking of proline-rich motif applied to carbon nanotube reveals unexpected subtleties underlying nanoparticle functionalization. Sci Rep 2014; 4:7229. [PMID: 25427563 PMCID: PMC4245522 DOI: 10.1038/srep07229] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 11/11/2014] [Indexed: 11/09/2022] Open
Abstract
Here, we report computational studies of the SH3 protein domain interacting with various single-walled carbon nanotubes (SWCNT) either bare or functionalized by mimicking the proline-rich motif (PRM) ligand (PPPVPPRR) and compare it to the SH3-PRM complex binding. With prolines or a single arginine attached, the SWCNT gained slightly on specificity when compared with the bare control, whereas with multi-arginine systems the specificity dropped dramatically to our surprise. Although the electrostatic interaction provided by arginines is crucial in the recognition between PRM and SH3 domain, our results suggest that attaching multiple arginines to the SWCNT has a detrimental effect on the binding affinity. Detailed analysis of the MD trajectories found two main factors that modulate the specificity of the binding: the existence of competing acidic patches at the surface of SH3 that leads to "trapping and clamping" by the arginines, and the rigidity of the SWCNT introducing entropic penalties in the proper binding. Further investigation revealed that the same "clamping" phenomenon exits in the PRM-SH3 system, which has not been reported in previous literature. The competing effects between nanoparticle and its functionalization components revealed by our model system should be of value to current and future nanomedicine designs.
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Interaction of amyloid inhibitor proteins with amyloid beta peptides: insight from molecular dynamics simulations. PLoS One 2014; 9:e113041. [PMID: 25422897 PMCID: PMC4244084 DOI: 10.1371/journal.pone.0113041] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/18/2014] [Indexed: 11/22/2022] Open
Abstract
Knowledge of the detailed mechanism by which proteins such as human αB- crystallin and human lysozyme inhibit amyloid beta (Aβ) peptide aggregation is crucial for designing treatment for Alzheimer's disease. Thus, unconstrained, atomistic molecular dynamics simulations in explicit solvent have been performed to characterize the Aβ17–42 assembly in presence of the αB-crystallin core domain and of lysozyme. Simulations reveal that both inhibitor proteins compete with inter-peptide interaction by binding to the peptides during the early stage of aggregation, which is consistent with their inhibitory action reported in experiments. However, the Aβ binding dynamics appear different for each inhibitor. The binding between crystallin and the peptide monomer, dominated by electrostatics, is relatively weak and transient due to the heterogeneous amino acid distribution of the inhibitor surface. The crystallin-bound Aβ oligomers are relatively long-lived, as they form more extensive contact surface with the inhibitor protein. In contrast, a high local density of arginines from lysozyme allows strong binding with Aβ peptide monomers, resulting in stable complexes. Our findings not only illustrate, in atomic detail, how the amyloid inhibitory mechanism of human αB-crystallin, a natural chaperone, is different from that of human lysozyme, but also may aid de novo design of amyloid inhibitors.
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Kang SG, Das P, McGrane SJ, Martin AJ, Huynh T, Royyuru AK, Taylor AJ, Jones PG, Zhou R. Molecular recognition of metabotropic glutamate receptor type 1 (mGluR1): synergistic understanding with free energy perturbation and linear response modeling. J Phys Chem B 2014; 118:6393-404. [PMID: 24635567 DOI: 10.1021/jp410232j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) constitute an important family of the G-protein coupled receptors. Due to their widespread distribution in the central nervous system (CNS), these receptors are attractive candidates for understanding the molecular basis of various cognitive processes as well as for designing inhibitors for relevant psychiatric and neurological disorders. Despite many studies on drugs targeting the mGluR receptors to date, the molecular level details on the ligand binding dynamics still remain unclear. In this study, we performed in silico experiments for mGluR1 with 29 different ligands including known synthetic agonists and antagonists as well as natural amino acids. The ligand-receptor binding affinities were estimated by the use of atomistic simulations combined with the mathematically rigorous, Free Energy Perturbation (FEP) method, which successfully recognized the native agonist l-glutamate among the highly favorable binders, and also accurately distinguished antagonists from agonists. Comparative contact analysis also revealed the binding mode differences between natural and non-natural amino acid-based ligands. Several factors potentially affecting the ligand binding affinity and specificity were identified including net charges, dipole moments, and the presence of aromatic rings. On the basis of these findings, linear response models (LRMs) were built for different sets of ligands that showed high correlations (R(2) > 0.95) to the corresponding FEP binding affinities. These results identify some key factors that determine ligand-mGluR1 binding and could be used for future inhibitor designs and support a role for in silico modeling for understanding receptor ligand interactions.
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Affiliation(s)
- Seung-gu Kang
- Computational Biology Center, IBM Thomas J. Watson Research Center , Yorktown Heights, New York 10598, United States
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35
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The complex and specific pMHC interactions with diverse HIV-1 TCR clonotypes reveal a structural basis for alterations in CTL function. Sci Rep 2014; 4:4087. [PMID: 24522437 PMCID: PMC3923210 DOI: 10.1038/srep04087] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 01/29/2014] [Indexed: 02/04/2023] Open
Abstract
Immune control of viral infections is modulated by diverse T cell receptor (TCR) clonotypes engaging peptide-MHC class I complexes on infected cells, but the relationship between TCR structure and antiviral function is unclear. Here we apply in silico molecular modeling with in vivo mutagenesis studies to investigate TCR-pMHC interactions from multiple CTL clonotypes specific for a well-defined HIV-1 epitope. Our molecular dynamics simulations of viral peptide-HLA-TCR complexes, based on two independent co-crystal structure templates, reveal that effective and ineffective clonotypes bind to the terminal portions of the peptide-MHC through similar salt bridges, but their hydrophobic side-chain packings can be very different, which accounts for the major part of the differences among these clonotypes. Non-specific hydrogen bonding to viral peptide also accommodates greater epitope variants. Furthermore, free energy perturbation calculations for point mutations on the viral peptide KK10 show excellent agreement with in vivo mutagenesis assays, with new predictions confirmed by additional experiments. These findings indicate a direct structural basis for heterogeneous CTL antiviral function.
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36
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Yang Z, Xia Z, Huynh T, King JA, Zhou R. Dissecting the contributions of β-hairpin tyrosine pairs to the folding and stability of long-lived human γD-crystallins. NANOSCALE 2014; 6:1797-807. [PMID: 24352614 PMCID: PMC3976203 DOI: 10.1039/c3nr03782g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Ultraviolet-radiation-induced damage to and aggregation of human lens crystallin proteins are thought to be a significant pathway to age-related cataract. The aromatic residues within the duplicated Greek key domains of γ- and β-crystallins are the main ultraviolet absorbers and are susceptible to direct and indirect ultraviolet damage. The previous site-directed mutagenesis studies have revealed a striking difference for two highly conserved homologous β-hairpin Tyr pairs, at the N-terminal domain (N-td) and C-terminal domain (C-td), respectively, in their contribution to the overall stability of HγD-Crys, but why they behave so differently still remains a mystery. In this paper, we systematically investigated the underlying molecular mechanism and detailed contributions of these two Tyr pairs with large scale molecular dynamics simulations. A series of different tyrosine-to-alanine pair(s) substitutions were performed in either the N-td, the C-td, or both. Our results suggest that the Y45A/Y50A pair substitution in the N-td mainly affects the stability of the N-td itself, while the Y133A/Y138A pair substitution in the C-td leads to a more cooperative unfolding of both N-td and C-td. The stability of motif 2 in the N-td is mainly determined by the interdomain interface, while motif 1 in the N-td or motifs 3 and 4 in the C-td are mainly stabilized by the intradomain hydrophobic core. The damage to any tyrosine pair(s) can directly introduce some apparent water leakage to the hydrophobic core at the interface, which in turn causes a serious loss in the stability of the N-td. However, for the C-td substitutions, it may further impair the stable "sandwich-like" Y133-R167-Y138 cluster (through cation-π interactions) in the wild-type, thus causing the loop regions near the residue A138 to undergo large fluctuations, which in turn results in the intrusion of water into the hydrophobic core of the C-td and induces the C-td to lose its stability. These findings help resolve the "mystery" on why these two Tyr pairs display such a striking difference in their contributions to the overall protein stability despite their highly homologous nature.
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Affiliation(s)
- Zaixing Yang
- Institute of Quantitative Biology and Medicine, SRMP and RAD-X & Collaborative Innovation Center of Suzhou Nano Science and Technology, Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou 215123, China.
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37
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Cai Z, Li J, Yin C, Yang Z, Wu J, Zhou R. Effect of urea concentration on aggregation of amyloidogenic hexapeptides (NFGAIL). J Phys Chem B 2013; 118:48-57. [PMID: 24328094 DOI: 10.1021/jp407776e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We have performed large-scale all-atom molecular dynamics (MD) simulations to study the aggregation behavior of four NFGAIL hexapeptides in the aqueous urea solution, with a urea concentration ranging from 0 to 5 M. We find that urea in general suppresses the peptide aggregation, but suppression slows down in the intermediation concentration regime around 3 M. Two competing mechanisms of urea are determined: urea molecules accumulated near the first solvation shell (FSS) tend to unfold the hexapeptide, which favors aggregation; on the other hand, the tight hydrogen bonds formed between urea and peptide mainchains hinder the association of peptides which disfavors the formation of the β-sheet. Furthermore, the different nonlinear urea concentration dependences of the urea-peptide and peptide-peptide hydrogen bonds lead to a nonmonotonic behavior, with a weak enhancement in the peptide aggregation around 3 M.
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Affiliation(s)
- Zhuowei Cai
- Department of Physics, Zhejiang University , Hangzhou, 310027, China
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38
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Shi B, Zuo G, Xiu P, Zhou R. Binding Preference of Carbon Nanotube Over Proline-Rich Motif Ligand on SH3-Domain: A Comparison with Different Force Fields. J Phys Chem B 2013; 117:3541-7. [DOI: 10.1021/jp312423y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Biyun Shi
- Bio-X Lab, Department of Physics, Zhejiang University, Hangzhou 310027, People’s
Republic of China
| | - Guanghong Zuo
- Shanghai
Institute of Applied
Physics, Chinese Academy of Sciences, P.O.
Box 800-204, Shanghai 201800, People’s Republic of China
- T-Life Research Center, Department
of Physics, Fudan University, Shanghai
200433, People’s Republic of China
| | - Peng Xiu
- Soft Matter Research Center
and Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027, People’s Republic of China
| | - Ruhong Zhou
- Soft Matter Research Center
and Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027, People’s Republic of China
- Computational Biology Center,
IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
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39
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Shao Q, Shi J, Zhu W. Molecular dynamics simulation indicating cold denaturation of β-hairpins. J Chem Phys 2013; 138:085102. [DOI: 10.1063/1.4792299] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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40
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Kang SG, Huynh T, Xia Z, Zhang Y, Fang H, Wei G, Zhou R. Hydrophobic interaction drives surface-assisted epitaxial assembly of amyloid-like peptides. J Am Chem Soc 2013; 135:3150-7. [PMID: 23360070 DOI: 10.1021/ja310989u] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The molecular mechanism of epitaxial fibril formation has been investigated for GAV-9 (NH(3)(+)-VGGAVVAGV-CONH(2)), an amyloid-like peptide extracted from a consensus sequence of amyloidogenic proteins, which assembles with very different morphologies, "upright" on mica and "flat" on the highly oriented pyrolytic graphite (HOPG). Our all-atom molecular dynamics simulations reveal that the strong electrostatic interaction induces the "upright" conformation on mica, whereas the hydrophobic interaction favors the "flat" conformation on HOPG. We also show that the epitaxial pattern on mica is ensured by the lattice matching between the anisotropic binding sites of the basal substrate and the molecular dimension of GAV-9, accompanied with a long-range order of well-defined β-strands. Furthermore, the binding free energy surfaces indicate that the longitudinal assembly growth is predominantly driven by the hydrophobic interaction along the longer crystallographic unit cell direction of mica. These findings provide a molecular basis for the surface-assisted molecular assembly, which might also be useful for the design of de novo nanodevices.
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Affiliation(s)
- Seung-gu Kang
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, USA
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41
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Yang Z, Xiu P, Shi B, Hua L, Zhou R. Coherent microscopic picture for urea-induced denaturation of proteins. J Phys Chem B 2012; 116:8856-62. [PMID: 22780326 DOI: 10.1021/jp304114h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In a previous study, we explored the mechanism of urea-induced denaturation of proteins by performing molecular dynamics (MD) simulations of hen lysozyme in 8 M urea and supported the "direct interaction mechanism" whereby urea denatures protein via dispersion interaction (Hua, L.; Zhou, R. H.; Thirumalai, D.; Berne, B. J. Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 16928). Here we perform large scale MD simulations of five representative protein/peptide systems in aqueous urea to investigate if the above mechanism is common to other proteins. In all cases, accumulations of urea around proteins/peptide are observed, suggesting that urea denatures proteins by directly attacking protein backbones and side chains rather than indirectly disrupting water structure as a "water breaker". Consistent with our previous case study of lysozyme, the current energetic analyses with five protein/peptide systems reveal that urea's preferential binding to proteins mainly comes from urea's stronger dispersion interactions with proteins than with bulk solution, whereas the electrostatic (hydrogen-bonded) interactions only play a relatively minor (even negative) role during this denaturation process. Furthermore, the simulations of the peptide system at different urea concentrations (8 and 4.5 M), and with different force fields (CHARMM and OPLSAA) suggest that the above mechanism is robust, independent of the urea concentration and force field used. Last, we emphasize the importance of periodic boundary conditions in pairwise energetic analyses. This article provides a comprehensive study on the physical mechanism of urea-induced protein denaturation and suggests that the "dispersion-interaction-driven" mechanism should be general.
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Affiliation(s)
- Zaixing Yang
- Department of Engineering Mechanics, and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, China
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42
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43
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Xia Z, Huynh T, Kang SG, Zhou R. Free-energy simulations reveal that both hydrophobic and polar interactions are important for influenza hemagglutinin antibody binding. Biophys J 2012; 102:1453-61. [PMID: 22455929 PMCID: PMC3309282 DOI: 10.1016/j.bpj.2012.01.043] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 01/25/2012] [Accepted: 01/27/2012] [Indexed: 11/24/2022] Open
Abstract
Antibodies binding to conserved epitopes can provide a broad range of neutralization to existing influenza subtypes and may also prevent the propagation of potential pandemic viruses by fighting against emerging strands. Here we propose a computational framework to study structural binding patterns and detailed molecular mechanisms of viral surface glycoprotein hemagglutinin (HA) binding with a broad spectrum of neutralizing monoclonal antibody fragments (Fab). We used rigorous free-energy perturbation (FEP) methods to calculate the antigen-antibody binding affinities, with an aggregate underlying molecular-dynamics simulation time of several microseconds (∼2 μs) using all-atom, explicit-solvent models. We achieved a high accuracy in the validation of our FEP protocol against a series of known binding affinities for this complex system, with <0.5 kcal/mol errors on average. We then introduced what to our knowledge are novel mutations into the interfacial region to further study the binding mechanism. We found that the stacking interaction between Trp-21 in HA2 and Phe-55 in the CDR-H2 of Fab is crucial to the antibody-antigen association. A single mutation of either W21A or F55A can cause a binding affinity decrease of ΔΔG > 4.0 kcal/mol (equivalent to an ∼1000-fold increase in the dissociation constant K(d)). Moreover, for group 1 HA subtypes (which include both the H1N1 swine flu and the H5N1 bird flu), the relative binding affinities change only slightly (< ±1 kcal/mol) when nonpolar residues at the αA helix of HA mutate to conservative amino acids of similar size, which explains the broad neutralization capability of antibodies such as F10 and CR6261. Finally, we found that the hydrogen-bonding network between His-38 (in HA1) and Ser-30/Gln-64 (in Fab) is important for preserving the strong binding of Fab against group 1 HAs, whereas the lack of such hydrogen bonds with Asn-38 in most group 2 HAs may be responsible for the escape of antibody neutralization. These large-scale simulations may provide new insight into the antigen-antibody binding mechanism at the atomic level, which could be essential for designing more-effective vaccines for influenza.
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Affiliation(s)
- Zhen Xia
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Tien Huynh
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York
| | - Seung-gu Kang
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York
| | - Ruhong Zhou
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York
- Department of Chemistry, Columbia University, New York, New York
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44
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Yang Z, Shi B, Lu H, Xiu P, Zhou R. Dewetting Transitions in the Self-Assembly of Two Amyloidogenic β-Sheets and the Importance of Matching Surfaces. J Phys Chem B 2011; 115:11137-44. [DOI: 10.1021/jp2046454] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Zaixing Yang
- Bio-X Lab, Department of Physics, and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, China
| | - Biyun Shi
- Bio-X Lab, Department of Physics, and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, China
| | - Hangjun Lu
- Department of Physics, Zhejiang Normal University, 321004, Jinhua, China
| | - Peng Xiu
- Bio-X Lab, Department of Physics, and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, China
| | - Ruhong Zhou
- Computational Biology Center, IBM Thomas J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, United States
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45
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Duan LL, Mei Y, Zhang D, Zhang QG, Zhang JZH. Folding of a helix at room temperature is critically aided by electrostatic polarization of intraprotein hydrogen bonds. J Am Chem Soc 2010; 132:11159-64. [PMID: 20698682 DOI: 10.1021/ja102735g] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report direct folding of a 17-residue helix protein (pdb:2I9M) by standard molecular dynamics simulation (single trajectory) at room temperature with implicit solvent. Starting from a fully extended structure, 2I9M successfully folds into the native conformation within 16 ns using adaptive hydrogen bond-specific charges to take into account the electrostatic polarization effect. Cluster analysis shows that conformations in the native state cluster have the highest population (78.4%) among all sampled conformations. Folding snapshots and the secondary structure analysis demonstrate that the folding of 2I9M begins at terminals and progresses toward the center. A plot of the free energy landscape indicates that there is no significant free energy barrier during folding, which explains the observed fast folding speed. For comparison, exactly the same molecular dynamics simulation but carried out under existing AMBER charges failed to fold 2I9M into native-like structures. The current study demonstrates that electrostatic polarization of intraprotein hydrogen bonding, which stabilizes the helix, is critical to the successful folding of 2I9m.
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Affiliation(s)
- Li L Duan
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
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46
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Gao M, She ZS, Zhou R. Key Residues that Play a Critical Role in Urea-Induced Lysozyme Unfolding. J Phys Chem B 2010; 114:15687-93. [DOI: 10.1021/jp1052453] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Meng Gao
- College of Engineering, Center for Theoretical Biology, and State Key Laboratory for Turbulence and Complex Systems, Peking University, Beijing 100871, China, Department of Chemistry, Columbia University, New York, New York 10027, United States, and Computational Biology Center, IBM Thomas J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, United States
| | - Zhen-Su She
- College of Engineering, Center for Theoretical Biology, and State Key Laboratory for Turbulence and Complex Systems, Peking University, Beijing 100871, China, Department of Chemistry, Columbia University, New York, New York 10027, United States, and Computational Biology Center, IBM Thomas J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, United States
| | - Ruhong Zhou
- College of Engineering, Center for Theoretical Biology, and State Key Laboratory for Turbulence and Complex Systems, Peking University, Beijing 100871, China, Department of Chemistry, Columbia University, New York, New York 10027, United States, and Computational Biology Center, IBM Thomas J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, United States
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47
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Tjong H, Zhou HX. The folding transition-state ensemble of a four-helix bundle protein: helix propensity as a determinant and macromolecular crowding as a probe. Biophys J 2010; 98:2273-80. [PMID: 20483336 DOI: 10.1016/j.bpj.2010.01.052] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 12/21/2009] [Accepted: 01/05/2010] [Indexed: 10/19/2022] Open
Abstract
The four-helix bundle protein Rd-apocyt b(562), a redesigned stable variant of apocytochrome b(562), exhibits two-state folding kinetics. Its transition-state ensemble has been characterized by Phi-value analysis. To elucidate the molecular basis of the transition-state ensemble, we have carried out high-temperature molecular dynamics simulations of the unfolding process. In six parallel simulations, unfolding started with the melting of helix I and the C-terminal half of helix IV, and followed by helix III, the N-terminal half of helix IV and helix II. This ordered melting of the helices is consistent with the conclusion from native-state hydrogen exchange, and can be rationalized by differences in intrinsic helix propensity. Guided by experimental Phi-values, a putative transition-state ensemble was extracted from the simulations. The residue helical probabilities of this transition-state ensemble show good correlation with the Phi-values. To further validate the putative transition-state ensemble, the effect of macromolecular crowding on the relative stability between the unfolded ensemble and the transition-state ensemble was calculated. The resulting effect of crowding on the folding kinetics agrees well with experimental observations. This study shows that molecular dynamics simulations combined with calculation of crowding effects provide an avenue for characterize the transition-state ensemble in atomic details.
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Affiliation(s)
- Harianto Tjong
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
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48
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Liu H, Yin P, He S, Sun Z, Tao Y, Huang Y, Zhuang H, Zhang G, Wei S. ATP-induced noncooperative thermal unfolding of hen lysozyme. Biochem Biophys Res Commun 2010; 397:598-602. [PMID: 20595053 DOI: 10.1016/j.bbrc.2010.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 06/01/2010] [Indexed: 10/19/2022]
Abstract
To understand the role of ATP underlying the enhanced amyloidosis of hen egg white lysozyme (HEWL), the synchrotron radiation circular dichroism, combined with tryptophan fluorescence, dynamic light-scattering, and differential scanning calorimetry, is used to examine the alterations of the conformation and thermal unfolding pathway of the HEWL in the presence of ATP, Mg(2+)-ATP, ADP, AMP, etc. It is revealed that the binding of ATP to HEWL through strong electrostatic interaction changes the secondary structures of HEWL and makes the exposed residue W62 move into hydrophobic environments. This alteration of W62 decreases the beta-domain stability of HEWL, induces a noncooperative unfolding of the secondary structures, and produces a partially unfolded intermediate. This intermediate containing relatively rich alpha-helix and less beta-sheet structures has a great tendency to aggregate. The results imply that the ease of aggregating of HEWL is related to the extent of denaturation of the amyloidogenic region, rather than the electrostatic neutralizing effect or monomeric beta-sheet enriched intermediate.
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Affiliation(s)
- Honglin Liu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People's Republic of China
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49
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Yan C, Pattani V, Tunnell JW, Ren P. Temperature-induced unfolding of epidermal growth factor (EGF): insight from molecular dynamics simulation. J Mol Graph Model 2010; 29:2-12. [PMID: 20466569 DOI: 10.1016/j.jmgm.2010.03.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 03/15/2010] [Accepted: 03/29/2010] [Indexed: 10/19/2022]
Abstract
Thermal disruption of protein structure and function is a potentially powerful therapeutic vehicle. With the emerging nanoparticle-targeting and femtosecond laser technology, it is possible to deliver heating locally to specific molecules. It is therefore important to understand how fast a protein can unfold or lose its function at high temperatures, such as near the water boiling point. In this study, the thermal damage of EGF was investigated by combining the replica exchange (136 replicas) and conventional molecular dynamics simulations. The REMD simulation was employed to rigorously explore the free-energy landscape of EGF unfolding. Interestingly, besides the native and unfolded states, we also observed a distinct molten globule (MG) state that retained substantial amount of native contacts. Based on the understanding that which the unfolding of EGF is a three-state process, we have examined the unfolding kinetics of EGF (N-->MG and MG-->D) with multiple 20-ns conventional MD simulations. The Arrhenius prefactors and activation energy barriers determined from the simulation are within the range of previously studied proteins. In contrast to the thermal damage of cells and tissues which take place on the time scale of seconds to hours at relatively low temperatures, the denaturation of proteins occur in nanoseconds when the temperature of heat bath approaches the boiling point.
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Affiliation(s)
- Chunli Yan
- Department of Biomedical Engineering, University of Texas, Austin, TX 78712, USA
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50
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Lin YW, Nie CM, Liao LF. Folding behaviors of apocytochrome b5 and its mutants: Insights from high temperature molecular dynamics simulations. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.theochem.2009.06.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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