1
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Shimono Y, Hakamada M, Mabuchi M. NPEX: Never give up protein exploration with deep reinforcement learning. J Mol Graph Model 2024; 131:108802. [PMID: 38838617 DOI: 10.1016/j.jmgm.2024.108802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/05/2024] [Accepted: 05/24/2024] [Indexed: 06/07/2024]
Abstract
Elucidating unknown structures of proteins, such as metastable states, is critical in designing therapeutic agents. Protein structure exploration has been performed using advanced computational methods, especially molecular dynamics and Markov chain Monte Carlo simulations, which require untenably long calculation times and prior structural knowledge. Here, we developed an innovative method for protein structure determination called never give up protein exploration (NPEX) with deep reinforcement learning. The NPEX method leverages the soft actor-critic algorithm and the intrinsic reward system, effectively adding a bias potential without the need for prior knowledge. To demonstrate the method's effectiveness, we applied it to four models: a double well, a triple well, the alanine dipeptide, and the tryptophan cage. Compared with Markov chain Monte Carlo simulations, NPEX had markedly greater sampling efficiency. The significantly enhanced computational efficiency and lack of prior domain knowledge requirements of the NPEX method will revolutionize protein structure exploration.
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Affiliation(s)
- Yuta Shimono
- Graduate School of Energy Science, Kyoto University, Yoshidahonmachi, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Masataka Hakamada
- Graduate School of Energy Science, Kyoto University, Yoshidahonmachi, Sakyo-ku, Kyoto, 606-8501, Japan.
| | - Mamoru Mabuchi
- Graduate School of Energy Science, Kyoto University, Yoshidahonmachi, Sakyo-ku, Kyoto, 606-8501, Japan
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2
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Bajpai S, Petkov BK, Tong M, Abreu CRA, Nair NN, Tuckerman ME. An interoperable implementation of collective-variable based enhanced sampling methods in extended phase space within the OpenMM package. J Comput Chem 2023; 44:2166-2183. [PMID: 37464902 DOI: 10.1002/jcc.27182] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/30/2023] [Accepted: 06/06/2023] [Indexed: 07/20/2023]
Abstract
Collective variable (CV)-based enhanced sampling techniques are widely used today for accelerating barrier-crossing events in molecular simulations. A class of these methods, which includes temperature accelerated molecular dynamics (TAMD)/driven-adiabatic free energy dynamics (d-AFED), unified free energy dynamics (UFED), and temperature accelerated sliced sampling (TASS), uses an extended variable formalism to achieve quick exploration of conformational space. These techniques are powerful, as they enhance the sampling of a large number of CVs simultaneously compared to other techniques. Extended variables are kept at a much higher temperature than the physical temperature by ensuring adiabatic separation between the extended and physical subsystems and employing rigorous thermostatting. In this work, we present a computational platform to perform extended phase space enhanced sampling simulations using the open-source molecular dynamics engine OpenMM. The implementation allows users to have interoperability of sampling techniques, as well as employ state-of-the-art thermostats and multiple time-stepping. This work also presents protocols for determining the critical parameters and procedures for reconstructing high-dimensional free energy surfaces. As a demonstration, we present simulation results on the high dimensional conformational landscapes of the alanine tripeptide in vacuo, tetra-N-methylglycine (tetra-sarcosine) peptoid in implicit solvent, and the Trp-cage mini protein in explicit water.
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Affiliation(s)
- Shitanshu Bajpai
- Department of Chemistry, Indian Institute of Technology Kanpur (IITK), Kanpur, India
| | - Brian K Petkov
- Department of Chemistry, New York University (NYU), New York, New York, USA
| | - Muchen Tong
- Department of Chemistry, New York University (NYU), New York, New York, USA
| | - Charlles R A Abreu
- Chemical Engineering Department, Escola de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nisanth N Nair
- Department of Chemistry, Indian Institute of Technology Kanpur (IITK), Kanpur, India
| | - Mark E Tuckerman
- Department of Chemistry, New York University (NYU), New York, New York, USA
- Courant Institute of Mathematical Sciences, New York University (NYU), New York, New York, USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China
- Simons Center for Computational Physical Chemistry, New York University, New York, New York, USA
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3
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Prasad S, Gupta M. Solvation of gold nanoparticles passivated with functionalized alkylthiols: A molecular dynamics study. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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4
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Zhang C, Zhao DX, Feng Y, Wang J, Yang ZZ. Energetics and J-coupling constants for Ala, Gly, and Val peptides demonstrated using ABEEM polarizable force field in vacuo and an aqueous solution. Phys Chem Chem Phys 2022; 24:4232-4250. [DOI: 10.1039/d1cp05676j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The development of an atom-bond electronegativity equalisation method at the σπ-level (ABEEM) polarisable force field (PFF) for peptides is presented. ABEEM PFF utilises a fluctuating charge model to explicitly describe...
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5
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Kapakayala AB, Nair NN. Boosting the conformational sampling by combining replica exchange with solute tempering and well-sliced metadynamics. J Comput Chem 2021; 42:2233-2240. [PMID: 34585768 DOI: 10.1002/jcc.26752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 08/30/2021] [Accepted: 09/12/2021] [Indexed: 01/22/2023]
Abstract
Methods that combine collective variable (CV) based enhanced sampling and global tempering approaches are used in speeding-up the conformational sampling and free energy calculation of large and soft systems with a plethora of energy minima. In this paper, a new method of this kind is proposed in which the well-sliced metadynamics approach (WSMTD) is united with replica exchange with solute tempering (REST2) method. WSMTD employs a divide-and-conquer strategy wherein high-dimensional slices of a free energy surface are independently sampled and combined. The method enables one to accomplish a controlled exploration of the CV-space with a restraining bias as in umbrella sampling, and enhance-sampling of one or more orthogonal CVs using a metadynamics like bias. The new hybrid method proposed here enables boosting the sampling of more slow degrees of freedom in WSMTD simulations, without the need to specify associated CVs, through a replica exchange scheme within the framework of REST2. The high-dimensional slices of the probability distributions of CVs computed from the united WSMTD and REST2 simulations are subsequently combined using the weighted histogram analysis method to obtain the free energy surface. We show that the new method proposed here is accurate, improves the conformational sampling, and achieves quick convergence in free energy estimates. We demonstrate this by computing the conformational free energy landscapes of solvated alanine tripeptide and Trp-cage mini protein in explicit water.
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Affiliation(s)
- Anji Babu Kapakayala
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India.,School of Pharmacy and Biomedical Sciences, Curtin University, Perth, Australia
| | - Nisanth N Nair
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, India
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6
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Heilmann N, Wolf M, Kozlowska M, Sedghamiz E, Setzler J, Brieg M, Wenzel W. Sampling of the conformational landscape of small proteins with Monte Carlo methods. Sci Rep 2020; 10:18211. [PMID: 33097750 PMCID: PMC7585447 DOI: 10.1038/s41598-020-75239-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/12/2020] [Indexed: 12/24/2022] Open
Abstract
Computer simulation provides an increasingly realistic picture of large-scale conformational change of proteins, but investigations remain fundamentally constrained by the femtosecond timestep of molecular dynamics simulations. For this reason, many biologically interesting questions cannot be addressed using accessible state-of-the-art computational resources. Here, we report the development of an all-atom Monte Carlo approach that permits the modelling of the large-scale conformational change of proteins using standard off-the-shelf computational hardware and standard all-atom force fields. We demonstrate extensive thermodynamic characterization of the folding process of the α-helical Trp-cage, the Villin headpiece and the β-sheet WW-domain. We fully characterize the free energy landscape, transition states, energy barriers between different states, and the per-residue stability of individual amino acids over a wide temperature range. We demonstrate that a state-of-the-art intramolecular force field can be combined with an implicit solvent model to obtain a high quality of the folded structures and also discuss limitations that still remain.
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Affiliation(s)
- Nana Heilmann
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Moritz Wolf
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Mariana Kozlowska
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Elaheh Sedghamiz
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Julia Setzler
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Martin Brieg
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Wolfgang Wenzel
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
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7
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Plamitzer L, Bouř P. Pressure dependence of vibrational optical activity of model biomolecules. A computational study. Chirality 2020; 32:710-721. [PMID: 32150771 DOI: 10.1002/chir.23216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 11/07/2022]
Abstract
Change of molecular properties with pressure is an attracting means to regulate molecular reactivity or biological activity. However, the effect is usually small and so far explored rather scarcely. To obtain a deeper insight and estimate the sensitivity of vibrational optical activity spectra to pressure-induced conformational changes, we investigate small model molecules. The Ala-Ala dipeptide, isomaltose disaccharide and adenine-uracil dinucleotide were chosen to represent three different biomolecular classes. The pressure effects were modeled by molecular dynamics and density functional theory simulations. The dinucleotide was found to be the most sensitive to the pressure, whereas for the disaccharide the smallest changes are predicted. Pressure-induced relative intensity changes in vibrational circular dichroism and Raman optical activity spectra are predicted to be 2-3-times larger than for non-polarized IR and Raman techniques.
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Affiliation(s)
- Luboš Plamitzer
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo náměstí 542/2, Prague 6, 166 10, Czech Republic.,Faculty of Mathematics and Physics, Charles University, Ke Karlovu 2027/3, Prague 2, 121 16, Czech Republic
| | - Petr Bouř
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo náměstí 542/2, Prague 6, 166 10, Czech Republic
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8
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Low temperature dependence of protein-water interactions on barstar surface: A nano-scale modelling. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.10.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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9
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Cai Z, Zhang Y. Hydrophobicity-driven unfolding of Trp-cage encapsulated between graphene sheets. Colloids Surf B Biointerfaces 2018; 168:103-108. [PMID: 29627125 DOI: 10.1016/j.colsurfb.2018.03.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 03/23/2018] [Accepted: 03/24/2018] [Indexed: 11/17/2022]
Abstract
Understanding the interaction between proteins and graphene not only helps elucidate the behaviors of proteins in confined geometries, but is also imperative to the development of a plethora of graphene-based biotechnologies, such as the graphene liquid cell transmission electron microscopy. To discuss the overall geometrical-thermal effects on proteins, we performed molecular dynamics simulations of hydrated Trp-cage miniprotein sandwiched between two graphene sheets and in the bulk environment at the temperatures below and above its unfolding temperature. The structural fluctuations of Trp-cage were characterized using the backbone root mean square displacement and the radius of gyration, from which the free energy landscape of Trp-cage was further constructed. We observed that at both temperatures the confined protein became adsorbed to the graphene surfaces and exhibited unfolded structures. Residue-specific analyses clearly showed the preference for the graphene to interact with the hydrophobic regions of Trp-cage. These results suggested that the conformation space accessible to the protein results from the competition between the thermodynamic driving forces and the geometrical restraints. While confinement usually tends to restrict the conformation of proteins by volume exclusion, it may also induce the unfolding of proteins by hydrophobic interactions.
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Affiliation(s)
- Zhikun Cai
- Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yang Zhang
- Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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10
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Gerig JT. Examination of ethanol interactions with Trp‐cage peptide through MD simulations and intermolecular nuclear Overhauser effects. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- John T. Gerig
- Department of Chemistry and Biochemistry University of California, Santa Barbara Santa Barbara CA USA
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11
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Gupta M, Khan TS, Agarwal M, Haider MA. Understanding the Nature of Amino Acid Interactions with Pd(111) or Pd-Au Bimetallic Catalysts in the Aqueous Phase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:1300-1310. [PMID: 29281290 DOI: 10.1021/acs.langmuir.7b03271] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The interaction of methionine (Met) with different bimetallic-segregated surfaces comprising a uniform distribution of strips and islands of Au on the Pd(111) surface was examined using molecular dynamics (MD) simulations. Out of all the segregated and uniformly doped surfaces studied, the design of Pd-Au islands showed some reduction in the interaction energy (Eint = -43.7 kJ/mol) as compared to that of the pure Pd(111) surface (Eint = -50 kJ/mol) for a single Met molecule. However, at a higher coverage of 9 Met molecules/simulation cell, none of the Pd-Au alloy surfaces showed any improvement as compared to the Pd(111) surface. In order to develop a comprehensive understanding of the nature of the nonbonded interaction of aqueous biogenic impurities with the Pd catalyst surface, the MD study was extended to include a variety of aliphatic, S-containing, aromatic, and polar amino acids. The potential of mean force (PMF) profiles were observed to be distinct for each class of amino acids with substantial differences among amino acids with acidic and basic side chains. The side chains of all the polar and aromatic amino acids showed direct contact with the surface while aliphatic amino acids had their hydrophobic side chain aligned away from the surface. Interestingly, lysine (Lys) and tyrosine (Tyr) were the only two amino acids which interacted preferentially via the distant backbone nitrogen and backbone oxygen, respectively, despite their side chains being in direct contact with the metal surface. The strength of interaction was correlated with the size of the amino acid; the interaction energies were observed to be the maximum for large molecules such as arginine (Arg, Eint = -87.7 kJ/mol) and tryptophan (Trp, Eint = -73.4 kJ/mol), while it was a minimum for aliphatic amino acids such as alanine (Ala, Eint = -10.9 kJ/mol). The study is focused on examining the sensitivity of the choice of the preferential interaction site, conformational preferences, and interaction energies to the side-chain specificity.
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Affiliation(s)
- Madhulika Gupta
- Renewable Energy and Chemicals Lab, Department of Chemical Engineering, ‡Department of Chemistry, and §Computer Services Centre, Indian Institute of Technology Delhi , Hauz Khas, Delhi 110016, India
| | - Tuhin S Khan
- Renewable Energy and Chemicals Lab, Department of Chemical Engineering, ‡Department of Chemistry, and §Computer Services Centre, Indian Institute of Technology Delhi , Hauz Khas, Delhi 110016, India
| | - Manish Agarwal
- Renewable Energy and Chemicals Lab, Department of Chemical Engineering, ‡Department of Chemistry, and §Computer Services Centre, Indian Institute of Technology Delhi , Hauz Khas, Delhi 110016, India
| | - M Ali Haider
- Renewable Energy and Chemicals Lab, Department of Chemical Engineering, ‡Department of Chemistry, and §Computer Services Centre, Indian Institute of Technology Delhi , Hauz Khas, Delhi 110016, India
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12
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Gupta M, Khatua P, Chakravarty C, Bandyopadhyay S. Hydration Behavior along the Folding Pathways of Trpzip4, Trpzip5 and Trpzip6. J Phys Chem B 2018; 122:1560-1572. [DOI: 10.1021/acs.jpcb.7b10135] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Madhulika Gupta
- Department
of Chemistry, Indian Institute of Technology-Delhi, New Delhi 110016, India
| | - Prabir Khatua
- Molecular
Modeling Laboratory, Department of Chemistry, Indian Institute of Technology-Kharagpur, Kharagpur 721302, India
| | - Charusita Chakravarty
- Department
of Chemistry, Indian Institute of Technology-Delhi, New Delhi 110016, India
| | - Sanjoy Bandyopadhyay
- Molecular
Modeling Laboratory, Department of Chemistry, Indian Institute of Technology-Kharagpur, Kharagpur 721302, India
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13
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Sieradzan AK, Lipska AG, Lubecka EA. Shielding effect in protein folding. J Mol Graph Model 2017; 79:118-132. [PMID: 29161634 DOI: 10.1016/j.jmgm.2017.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/19/2017] [Accepted: 10/20/2017] [Indexed: 01/01/2023]
Abstract
One of the most important interactions responsible for protein folding and stability are hydrogen bonds between peptide groups. There is a constant competition between the water molecules and peptide groups in a hydrogen bond formation. Also side-chains take part in this process by reducing hydration of peptide group (shielding effect) that promotes the protein folding. In this paper, a new approach to take into account a shielding effect is presented. A modification of the energy function is derived and incorporated into the UNited RESidue (UNRES) force field. Canonical Molecular Dynamics and Replica Exchange Molecular Dynamics with UNRES force field is applied to study the influence of this effect on protein structure, folding kinetics and free energy landscapes. The results of test calculations suggest that even small contribution of this effect into energy function changes force field behavior as well as speeds up the folding process significantly.
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Affiliation(s)
- Adam K Sieradzan
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
| | - Agnieszka G Lipska
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Emilia A Lubecka
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; Institute of Informatics, University of Gdańsk, Wita Stwosza 57, 80-308 Gdańsk, Poland
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14
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Gupta M, Khan TS, Gupta S, Alam MI, Agarwal M, Haider MA. Non-bonding and bonding interactions of biogenic impurities with the metal catalyst and the design of bimetallic alloys. J Catal 2017. [DOI: 10.1016/j.jcat.2017.06.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Menon S, Sengupta N. Influence of Hyperglycemic Conditions on Self-Association of the Alzheimer's Amyloid β (Aβ 1-42) Peptide. ACS OMEGA 2017; 2:2134-2147. [PMID: 30023655 PMCID: PMC6044820 DOI: 10.1021/acsomega.7b00018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 05/08/2017] [Indexed: 06/08/2023]
Abstract
Clinical studies have identified a correlation between type-2 diabetes mellitus and cognitive decrements en route to the onset of Alzheimer's disease (AD). Recent studies have established that post-translational modifications of the amyloid β (Aβ) peptide occur under hyperglycemic conditions; particularly, the process of glycation exacerbates its neurotoxicity and accelerates AD progression. In view of the assertion that macromolecular crowding has an altering effect on protein self-assembly, it is crucial to characterize the effects of hyperglycemic conditions via crowding on Aβ self-assembly. Toward this purpose, fully atomistic molecular dynamics simulations were performed to study the effects of glucose crowding on Aβ dimerization, which is the smallest known neurotoxic species. The dimers formed in the glucose-crowded environment were found to have weaker associations as compared to that of those formed in water. Binding free energy calculations show that the reduced binding strength of the dimers can be mainly attributed to the overall weakening of the dispersion interactions correlated with substantial loss of interpeptide contacts in the hydrophobic patches of the Aβ units. Analysis to discern the differential solvation pattern in the glucose-crowded and pure water systems revealed that glucose molecules cluster around the protein, at a distance of 5-7 Å, which traps the water molecules in close association with the protein surface. This preferential exclusion of glucose molecules and resulting hydration of the Aβ peptides has a screening effect on the hydrophobic interactions, which in turn diminishes the binding strength of the resulting dimers. Our results imply that physical effects attributed to crowded hyperglycemic environments are incapable of solely promoting Aβ self-assembly, indicating that further mechanistic studies are required to provide insights into the self-assembly of post-translationally modified Aβ peptides, known to possess aggravated toxicity, under these conditions.
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Affiliation(s)
- Sneha Menon
- Physical
Chemistry Division, CSIR-National Chemical
Laboratory, Dr. Homi
Bhabha Road, Pune 411008, India
- Academy
of Scientific and Innovative Research (AcSIR), Training and Development Complex, CSIR Campus,
CSIR Road, Chennai 600113, India
| | - Neelanjana Sengupta
- Department
of Biological Sciences, Indian Institute
of Science Education and Research (IISER) Kolkata, Mohanpur 741246, West Bengal, India
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16
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Gupta M, Khatua P, Chakravarty C, Bandyopadhyay S. The sensitivity of folding free energy landscapes of trpzips to mutations in the hydrophobic core. Phys Chem Chem Phys 2017; 19:22813-22825. [DOI: 10.1039/c7cp03825a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The sensitivity of the stability of folded states and free energy landscapes to the differences in the hydrophobic content of the core residues has been studied for the set of 16-residue trpzips, namely, Trpzip4, Trpzip5 and Trpzip6.
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Affiliation(s)
- Madhulika Gupta
- Department of Chemistry
- Indian Institute of Technology-Delhi
- New Delhi 110016
- India
| | - Prabir Khatua
- Molecular Modeling Laboratory
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | | | - Sanjoy Bandyopadhyay
- Molecular Modeling Laboratory
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
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