1
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Nguan H, Ishak KA, Zahid NI, Martinez-Felipe A, Hashim R, Aripin NFK. Incommensurate lamellar phase from long chain Mannosides: Investigation by X-Ray scattering and replica exchange molecular dynamics (REMD). J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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2
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Dong S, Luo S, Huang K, Zhao X, Duan L, Li H. Insights into four helical proteins folding via self-guided Langevin dynamics simulation. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1874558] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Shuheng Dong
- School of Physics and Electronics, Shandong Normal University, Jinan, People’s Republic of China
| | - Song Luo
- School of Physics and Electronics, Shandong Normal University, Jinan, People’s Republic of China
| | - Kaifang Huang
- School of Physics and Electronics, Shandong Normal University, Jinan, People’s Republic of China
| | - Xiaoyu Zhao
- School of Physics and Electronics, Shandong Normal University, Jinan, People’s Republic of China
| | - Lili Duan
- School of Physics and Electronics, Shandong Normal University, Jinan, People’s Republic of China
| | - Hao Li
- School of Physics and Electronics, Shandong Normal University, Jinan, People’s Republic of China
- Department of Science and Technology, Shandong Normal University, Jinan, People’s Republic of China
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3
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Rapallo A, Gaspari R, Grasso G, Danani A. Extended diffusion theory: Recovering dynamics from biased/accelerated molecular simulations. J Comput Chem 2020; 42:586-599. [PMID: 33351966 DOI: 10.1002/jcc.26474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/09/2020] [Accepted: 12/02/2020] [Indexed: 11/08/2022]
Abstract
Dynamical properties are of great importance in determining the behavior of synthetic and natural molecules, but capturing them by computational methods is a nontrivial task. Very often the time scales of the relevant phenomena are far beyond the typical time windows accessible by classical Molecular Dynamics (MD) simulations, currently limited to the order of microseconds on standard laboratory workstations. On the other hand, biased and accelerated simulations allow for fast and thorough exploration of the molecular conformational space, but they lose the dynamic information. The problem of recovering dynamics from biased/accelerated simulations is a very active field of research, but no totally robust/reliable solutions have been given yet. In this paper it is shown how the Smoluchowski equation, in the framework of Diffusion Theory (DT), can be used to bridge this gap, and dynamical properties, in the form of time correlation functions (TCFs), can be extracted also from such kind of simulations. DT is first extended (EDT) to express the mobility tensors entering the Smoluchowski operator in terms of a recently introduced unified and regularized Rotne-Prager-Yamakawa approximation, [P. J. Zuk, E. Wajnryb, K. A. Mizerski, P. Szymczak, J. Fluid. Mech. 2014, 741, R5, 1-13] also involving mixed rotation-translation contributions, and rotation-rotation terms beside the classical translation-translation ones, so far used in DT. Then, the method is applied to recover the dynamics of a nontrivial example of a peptide in explicit water from the first 200 ns of a Replica Exchange Molecular Dynamics simulation, which is a popular computational method that destroys the long time dynamics. EDT dynamics were found to favorably compare against those coming from a standard MD simulation of the same system, requiring a time window of 30 μs to converge. This result shows that EDT is a tool of practical value to recover the long time dynamics of systems in diffusive regimes from biased/accelerated simulations, to be exploited in those cases when direct evaluation by standard MD is unfeasible.
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Affiliation(s)
- Arnaldo Rapallo
- CNR - Istituto di Scienze e Tecnologie Chimiche "Giulio Natta" (SCITEC), Milano, Italy
| | - Roberto Gaspari
- CNR - Istituto di Scienze e Tecnologie Chimiche "Giulio Natta" (SCITEC), Milano, Italy
| | - Gianvito Grasso
- Dalle Molle Institute for Artificial Intelligence (IDSIA), Università della Svizzera italiana (USI), Scuola Universitaria Professionale della Svizzera italiana (SUPSI), Lugano-Viganello, Switzerland
| | - Andrea Danani
- Dalle Molle Institute for Artificial Intelligence (IDSIA), Università della Svizzera italiana (USI), Scuola Universitaria Professionale della Svizzera italiana (SUPSI), Lugano-Viganello, Switzerland
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4
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Miceli M, Muscat S, Morbiducci U, Cavaglià M, Deriu MA. Ultrasonic waves effect on S-shaped β-amyloids conformational dynamics by non-equilibrium molecular dynamics. J Mol Graph Model 2020; 96:107518. [DOI: 10.1016/j.jmgm.2019.107518] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 12/16/2019] [Accepted: 12/20/2019] [Indexed: 12/15/2022]
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5
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Elucidating the Effect of Static Electric Field on Amyloid Beta 1-42 Supramolecular Assembly. J Mol Graph Model 2020; 96:107535. [PMID: 31978828 DOI: 10.1016/j.jmgm.2020.107535] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 12/06/2019] [Accepted: 01/09/2020] [Indexed: 02/07/2023]
Abstract
Amyloid-β (Aβ) aggregation is recognized to be a key toxic factor in the pathogenesis of Alzheimer disease, which is the most common progressive neurodegenerative disorder. In vitro experiments have elucidated that Aβ aggregation depends on several factors, such as pH, temperature and peptide concentration. Despite the research effort in this field, the fundamental mechanism responsible for the disease progression is still unclear. Recent research has proposed the application of electric fields as a non-invasive therapeutic option leading to the disruption of amyloid fibrils. In this regard, a molecular level understanding of the interactions governing the destabilization mechanism represents an important research advancement. Understanding the electric field effects on proteins, provides a more in-depth comprehension of the relationship between protein conformation and electrostatic dipole moment. The present study focuses on investigating the effect of static Electric Field (EF) on the conformational dynamics of Aβ fibrils by all-atom Molecular Dynamics (MD) simulations. The outcome of this work provides novel insight into this research field, demonstrating how the Aβ assembly may be destabilized by the applied EF.
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6
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Dal Magro R, Simonelli S, Cox A, Formicola B, Corti R, Cassina V, Nardo L, Mantegazza F, Salerno D, Grasso G, Deriu MA, Danani A, Calabresi L, Re F. The Extent of Human Apolipoprotein A-I Lipidation Strongly Affects the β-Amyloid Efflux Across the Blood-Brain Barrier in vitro. Front Neurosci 2019; 13:419. [PMID: 31156358 PMCID: PMC6532439 DOI: 10.3389/fnins.2019.00419] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/11/2019] [Indexed: 12/20/2022] Open
Abstract
Much evidence suggests a protective role of high-density lipoprotein (HDL) and its major apolipoprotein apoA-I, in Alzheimer's disease (AD). The biogenesis of nascent HDL derived from a first lipidation of apoA-I, which is synthesized by the liver and intestine but not in the brain, in a process mediated by ABCA1. The maturation of nascent HDL in mature spherical HDL is due to a subsequent lipidation step, LCAT-mediated cholesterol esterification, and the change of apoA-I conformation. Therefore, different subclasses of apoA-I-HDL simultaneously exist in the blood circulation. Here, we investigated if and how the lipidation state affects the ability of apoA-I-HDL to target and modulate the cerebral β-amyloid (Aβ) content from the periphery, that is thus far unclear. In particular, different subclasses of HDL, each with different apoA-I lipidation state, were purified from human plasma and their ability to cross the blood-brain barrier (BBB), to interact with Aβ aggregates, and to affect Aβ efflux across the BBB was assessed in vitro using a transwell system. The results showed that discoidal HDL displayed a superior capability to promote Aβ efflux in vitro (9 × 10-5 cm/min), when compared to apoA-I in other lipidation states. In particular, no effect on Aβ efflux was detected when apoA-I was in mature spherical HDL, suggesting that apoA-I conformation, and lipidation could play a role in Aβ clearance from the brain. Finally, when apoA-I folded its structure in discoidal HDL, rather than in spherical ones, it was able to cross the BBB in vitro and strongly destabilize the conformation of Aβ fibrils by decreasing the order of the fibril structure (-24%) and the β-sheet content (-14%). These data suggest that the extent of apoA-I lipidation, and consequently its conformation, may represent crucial features that could exert their protective role in AD pathogenesis.
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Affiliation(s)
- Roberta Dal Magro
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Sara Simonelli
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro Grossi Paoletti, Università degli Studi di Milano, Milan, Italy
| | - Alysia Cox
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Beatrice Formicola
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Roberta Corti
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Valeria Cassina
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Luca Nardo
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Francesco Mantegazza
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Domenico Salerno
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
| | - Gianvito Grasso
- Istituto Dalle Molle di Studi sull’Intelligenza Artificiale, Scuola Universitaria Professionale della Svizzera Italiana, Università della Svizzera Italiana, Manno, Switzerland
| | - Marco Agostino Deriu
- Istituto Dalle Molle di Studi sull’Intelligenza Artificiale, Scuola Universitaria Professionale della Svizzera Italiana, Università della Svizzera Italiana, Manno, Switzerland
| | - Andrea Danani
- Istituto Dalle Molle di Studi sull’Intelligenza Artificiale, Scuola Universitaria Professionale della Svizzera Italiana, Università della Svizzera Italiana, Manno, Switzerland
| | - Laura Calabresi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Centro Grossi Paoletti, Università degli Studi di Milano, Milan, Italy
| | - Francesca Re
- School of Medicine and Surgery, Nanomedicine Center NANOMIB, University of Milano-Bicocca, Monza, Italy
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7
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Munsamy G, Agoni C, Soliman MES. A dual target of Plasmepsin IX and X: Unveiling the atomistic superiority of a core chemical scaffold in malaria therapy. J Cell Biochem 2019; 120:7876-7887. [PMID: 30430636 DOI: 10.1002/jcb.28062] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 10/22/2018] [Indexed: 01/24/2023]
Abstract
Plasmepsin IX and X, members of the prominent aspartic family of proteases whose function were hitherto unknown have only recently been established as key mediators of erythrocyte invasion and egress of the virulent malarial parasite. Inhibitor 49c, a potent antimalarial peptidomimetic inhibitor initially developed to target Plasmepsin II has lately been proven to exhibit potent inhibitory activity against Plasmepsin IX and X. However, the molecular and structural dynamics supporting its inhibitory activity remain inconclusive. Hindering the motion of the flap and hinge region of an aspartic protease remains essential for disabling the catalytic activity of the enzyme. Integrating molecular dynamic simulations coupled with other advanced biocomputational tools, we reveal the enhanced structural mechanistic competence of 49c in complex with Plasmepsin IX and X relative to Pepstatin. Pepstatin, a known aspartic protease inhibitor which actively hinders the opening and closing of the flap tip and flexible loop and consequently limits access to the catalytic aspartic residues, however, its administration has been related to elevated levels of toxicity. Thermodynamic calculations reveal a higher relative binding free energy associated with Plasmepsin IX and X in complex with 49c as opposed to Pepstatin. A relatively compact and structurally rigid 49c bound complexes sequel into the restriction of the flap and hinge residues by restraining cohesive movement, consequently hindering their "twisting motion" from transpiring. Findings unveil an atomistic perspective into the structural superiority of 49c in complex with Plasmepsin IX and X.
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Affiliation(s)
- Geraldene Munsamy
- Department of Pharmaceutical Chemistry, Molecular Bio-Computation and Drug Design Laboratory, School of Health Sciences, Westville Campus, University of KwaZulu-Natal, Durban, South Africa
| | - Clement Agoni
- Department of Pharmaceutical Chemistry, Molecular Bio-Computation and Drug Design Laboratory, School of Health Sciences, Westville Campus, University of KwaZulu-Natal, Durban, South Africa
| | - Mahmoud E S Soliman
- Department of Pharmaceutical Chemistry, Molecular Bio-Computation and Drug Design Laboratory, School of Health Sciences, Westville Campus, University of KwaZulu-Natal, Durban, South Africa
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8
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Grasso G, Morbiducci U, Massai D, Tuszynski JA, Danani A, Deriu MA. Destabilizing the AXH Tetramer by Mutations: Mechanisms and Potential Antiaggregation Strategies. Biophys J 2019; 114:323-330. [PMID: 29401430 DOI: 10.1016/j.bpj.2017.11.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/03/2017] [Accepted: 11/20/2017] [Indexed: 01/12/2023] Open
Abstract
The AXH domain of protein Ataxin 1 is thought to play a key role in the misfolding and aggregation pathway responsible for Spinocerebellar ataxia 1. For this reason, a molecular level understanding of AXH oligomerization pathway is crucial to elucidate the aggregation mechanism, which is thought to trigger the disease. This study employs classical and enhanced molecular dynamics to identify the structural and energetic basis of AXH tetramer stability. Results of this work elucidate molecular mechanisms behind the destabilizing effect of protein mutations, which consequently affect the AXH tetramer assembly. Moreover, results of the study draw attention for the first time, to our knowledge, to the R638 protein residue, which is shown to play a key role in AXH tetramer stability. Therefore, R638 might be also implicated in the AXH oligomerization pathway and stands out as a target for future experimental studies focused on self-association mechanisms and fibril formation of full-length ATX1.
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Affiliation(s)
- Gianvito Grasso
- Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Università della Svizzera Italiana (USI), Manno, Switzerland
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Torino, Italy
| | - Diana Massai
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Torino, Italy
| | - Jack A Tuszynski
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Andrea Danani
- Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Università della Svizzera Italiana (USI), Manno, Switzerland
| | - Marco A Deriu
- Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Università della Svizzera Italiana (USI), Manno, Switzerland.
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9
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Visentin C, Navarro S, Grasso G, Regonesi ME, Deriu MA, Tortora P, Ventura S. Protein Environment: A Crucial Triggering Factor in Josephin Domain Aggregation: The Role of 2,2,2-Trifluoroethanol. Int J Mol Sci 2018; 19:ijms19082151. [PMID: 30042316 PMCID: PMC6121581 DOI: 10.3390/ijms19082151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 11/28/2022] Open
Abstract
The protein ataxin-3 contains a polyglutamine stretch that triggers amyloid aggregation when it is expanded beyond a critical threshold. This results in the onset of the spinocerebellar ataxia type 3. The protein consists of the globular N-terminal Josephin domain and a disordered C-terminal tail where the polyglutamine stretch is located. Expanded ataxin-3 aggregates via a two-stage mechanism: first, Josephin domain self-association, then polyQ fibrillation. This highlights the intrinsic amyloidogenic potential of Josephin domain. Therefore, much effort has been put into investigating its aggregation mechanism(s). A key issue regards the conformational requirements for triggering amyloid aggregation, as it is believed that, generally, misfolding should precede aggregation. Here, we have assayed the effect of 2,2,2-trifluoroethanol, a co-solvent capable of stabilizing secondary structures, especially α-helices. By combining biophysical methods and molecular dynamics, we demonstrated that both secondary and tertiary JD structures are virtually unchanged in the presence of up to 5% 2,2,2-trifluoroethanol. Despite the preservation of JD structure, 1% of 2,2,2-trifluoroethanol suffices to exacerbate the intrinsic aggregation propensity of this domain, by slightly decreasing its conformational stability. These results indicate that in the case of JD, conformational fluctuations might suffice to promote a transition towards an aggregated state without the need for extensive unfolding, and highlights the important role played by the environment on the aggregation of this globular domain.
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Affiliation(s)
- Cristina Visentin
- Institut de Biotecnologia i de Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
| | - Susanna Navarro
- Institut de Biotecnologia i de Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
| | - Gianvito Grasso
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera italiana (SUPSI), Università della Svizzera italiana (USI), CH-6928 Manno, Switzerland.
| | - Maria Elena Regonesi
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 20126 Milano, Italy.
- Centro di Neuroscienze di Milano (Neuro-MI), 20126 Milano, Italy.
| | - Marco Agostino Deriu
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera italiana (SUPSI), Università della Svizzera italiana (USI), CH-6928 Manno, Switzerland.
| | - Paolo Tortora
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 20126 Milano, Italy.
- Centro di Neuroscienze di Milano (Neuro-MI), 20126 Milano, Italy.
| | - Salvador Ventura
- Institut de Biotecnologia i de Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
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Grasso G, Rebella M, Muscat S, Morbiducci U, Tuszynski J, Danani A, Deriu MA. Conformational Dynamics and Stability of U-Shaped and S-Shaped Amyloid β Assemblies. Int J Mol Sci 2018; 19:ijms19020571. [PMID: 29443891 PMCID: PMC5855793 DOI: 10.3390/ijms19020571] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/04/2018] [Accepted: 02/10/2018] [Indexed: 11/16/2022] Open
Abstract
Alzheimer’s disease is the most fatal neurodegenerative disorder characterized by the aggregation and deposition of Amyloid β (Aβ) oligomers in the brain of patients. Two principal variants of Aβ exist in humans: Aβ1–40 and Aβ1–42. The former is the most abundant in the plaques, while the latter is the most toxic species and forms fibrils more rapidly. Interestingly, fibrils of Aβ1–40 peptides can only assume U-shaped conformations while Aβ1–42 can also arrange as S-shaped three-stranded chains, as recently discovered. As alterations in protein conformational arrangement correlate with cell toxicity and speed of disease progression, it is important to characterize, at molecular level, the conformational dynamics of amyloid fibrils. In this work, Replica Exchange Molecular Dynamics simulations were carried out to compare the conformational dynamics of U-shaped and S-shaped Aβ17–42 small fibrils. Our computational results provide support for the stability of the recently proposed S-shaped model due to the maximized interactions involving the C-terminal residues. On the other hand, the U-shaped motif is characterized by significant distortions resulting in a more disordered assembly. Outcomes of our work suggest that the molecular architecture of the protein aggregates might play a pivotal role in formation and conformational stability of the resulting fibrils.
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Affiliation(s)
- Gianvito Grasso
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Università della Svizzera Italiana (USI), Centro Galleria 2, CH-6928 Manno, Switzerland.
| | - Martina Rebella
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128 Torino, Italy.
| | - Stefano Muscat
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128 Torino, Italy.
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128 Torino, Italy.
| | - Jack Tuszynski
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128 Torino, Italy.
- Department of Physics, University of Alberta, Edmonton, AB T6G 2R3, Canada.
| | - Andrea Danani
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Università della Svizzera Italiana (USI), Centro Galleria 2, CH-6928 Manno, Switzerland.
| | - Marco A Deriu
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Università della Svizzera Italiana (USI), Centro Galleria 2, CH-6928 Manno, Switzerland.
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11
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Deriu MA, Cangiotti M, Grasso G, Licandro G, Lavasanifar A, Tuszynski JA, Ottaviani MF, Danani A. Self-Assembled Ligands Targeting TLR7: A Molecular Level Investigation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:14460-14471. [PMID: 29200306 DOI: 10.1021/acs.langmuir.7b03168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Toll-like receptors (TLRs) are pattern recognition transmembrane proteins that play an important role in innate immunity. In particular, TLR7 plays a role in detecting nucleic acids derived from viruses and bacteria. The huge number of pathologies in which TLR7 is involved has led to an increasing interest in developing new compounds targeting this protein. Several conjugation strategies were proposed for TLR7 agonists to increase the potency while maintaining a low toxicity. In this work, we focus the attention on two promising classes of TLR7 compounds derived from the same pharmacophore conjugated with phospholipid and polyethylene glycol (PEG). A multidisciplinary investigation has been carried out by molecular dynamics (MD), dynamic light scattering (DLS), electron paramagnetic resonance (EPR), and cytotoxicity assessment. DLS and MD indicated how only the phospholipid conjugation provides the compound abilities to self-assemble in an orderly fashion with a maximal pharmacophore exposition to the solvent. Further EPR and cytotoxicity experiments highlighted that phospholipid compounds organize in stable aggregates and well interact with TLR7, whereas PEG conjugation was characterized by poorly stable aggregates at the cells surface. The methodological framework proposed in this study may be used to investigate, at a molecular level, the interactions generally occurring between aggregated ligands, to be used as drugs, and protein receptors.
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Affiliation(s)
- Marco A Deriu
- Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Università della Svizzera Italiana (USI) , Manno CH-6928, Switzerland
| | - Michela Cangiotti
- Department of Pure and Applied Sciences, University of Urbino , Via Ca' Le Suore 2/4, Urbino,Marche 61029, Italy
| | - Gianvito Grasso
- Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Università della Svizzera Italiana (USI) , Manno CH-6928, Switzerland
| | - Ginevra Licandro
- Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Università della Svizzera Italiana (USI) , Manno CH-6928, Switzerland
| | | | | | - Maria Francesca Ottaviani
- Department of Pure and Applied Sciences, University of Urbino , Via Ca' Le Suore 2/4, Urbino,Marche 61029, Italy
| | - Andrea Danani
- Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Università della Svizzera Italiana (USI) , Manno CH-6928, Switzerland
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12
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Grasso G, Deriu MA, Patrulea V, Borchard G, Möller M, Danani A. Free energy landscape of siRNA-polycation complexation: Elucidating the effect of molecular geometry, polymer flexibility, and charge neutralization. PLoS One 2017; 12:e0186816. [PMID: 29088239 PMCID: PMC5663398 DOI: 10.1371/journal.pone.0186816] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 10/09/2017] [Indexed: 12/16/2022] Open
Abstract
The success of medical threatments with DNA and silencing interference RNA is strongly related to the design of efficient delivery technologies. Cationic polymers represent an attractive strategy to serve as nucleic-acid carriers with the envisioned advantages of efficient complexation, low cost, ease of production, well-defined size, and low polydispersity index. However, the balance between efficacy and toxicity (safety) of these polymers is a challenge and in need of improvement. With the aim of designing more effective polycationic-based gene carriers, many parameters such as carrier morphology, size, molecular weight, surface chemistry, and flexibility/rigidity ratio need to be taken into consideration. In the present work, the binding mechanism of three cationic polymers (polyarginine, polylysine and polyethyleneimine) to a model siRNA target is computationally investigated at the atomistic level. In order to better understand the polycationic carrier-siRNA interactions, replica exchange molecular dynamic simulations were carried out to provide an exhaustive exploration of all the possible binding sites, taking fully into account the siRNA flexibility together with the presence of explicit solvent and ions. Moreover, well-tempered metadynamics simulations were employed to elucidate how molecular geometry, polycation flexibility, and charge neutralization affect the siRNA-polycations free energy landscape in term of low-energy binding modes and unbinding free energy barriers. Significant differences among polymer binding modes have been detected, revealing the advantageous binding properties of polyarginine and polylysine compared to polyethyleneimine.
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Affiliation(s)
- Gianvito Grasso
- Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Università della Svizzera Italiana (USI), Centro Galleria 2, Manno, Switzerland
| | - Marco Agostino Deriu
- Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Università della Svizzera Italiana (USI), Centro Galleria 2, Manno, Switzerland
| | - Viorica Patrulea
- School of Pharmaceutical Sciences, University of Geneva, Rue Michel-Servet 1, Geneva, Switzerland
| | - Gerrit Borchard
- School of Pharmaceutical Sciences, University of Geneva, Rue Michel-Servet 1, Geneva, Switzerland
| | - Michael Möller
- School of Pharmaceutical Sciences, University of Geneva, Rue Michel-Servet 1, Geneva, Switzerland
| | - Andrea Danani
- Istituto Dalle Molle di Studi Sull'Intelligenza Artificiale (IDSIA), Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), Università della Svizzera Italiana (USI), Centro Galleria 2, Manno, Switzerland
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Lepre MG, Omar SI, Grasso G, Morbiducci U, Deriu MA, Tuszynski JA. Insights into the Effect of the G245S Single Point Mutation on the Structure of p53 and the Binding of the Protein to DNA. Molecules 2017; 22:E1358. [PMID: 28813011 PMCID: PMC6152093 DOI: 10.3390/molecules22081358] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 08/13/2017] [Accepted: 08/13/2017] [Indexed: 12/20/2022] Open
Abstract
The transcription factor p53 is a potent tumor suppressor dubbed as the "guardian of the genome" because of its ability to orchestrate protective biological outputs in response to a variety of oncogenic stresses. Mutation and thus inactivation of p53 can be found in 50% of human tumors. The majority are missense mutations located in the DNA binding region. Among them, G245S is known to be a structural hotspot mutation. To understand the behaviors and differences between the wild-type and mutant, both a dimer of the wild type p53 (wt-p53) and its G245S mutant (G245S-mp53), complexed with DNA, were simulated using molecular dynamics for more than 1 μs. wt-p53 and G245S-mp53 apo monomers were simulated for 1 μs as well. Conformational analyses and binding energy evaluations performed underline important differences and therefore provide insights to understand the G245S-mp53 loss of function. Our results indicate that the G245S mutation destabilizes several structural regions in the protein that are crucial for DNA binding when found in its apo form and highlight differences in the mutant-DNA complex structure compared to the wt protein. These findings not only provide means that can be applied to other p53 mutants but also serve as structural basis for further studies aimed at the development of cancer therapies based on restoring the function of p53.
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Affiliation(s)
- Marco Gaetano Lepre
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy.
| | - Sara Ibrahim Omar
- Department of Oncology, University of Alberta, Edmonton, AB T6G 2R3, Canada.
| | - Gianvito Grasso
- Istituto Dalle Molle di studi sull'Intelligenza Artificiale (IDSIA), Scuola universitaria professionale della Svizzera italiana (SUPSI), Università della Svizzera italiana (USI), Centro Galleria 2, CH-6928 Manno, Switzerland.
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy.
| | - Marco Agostino Deriu
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, 10129 Torino, Italy.
- Istituto Dalle Molle di studi sull'Intelligenza Artificiale (IDSIA), Scuola universitaria professionale della Svizzera italiana (SUPSI), Università della Svizzera italiana (USI), Centro Galleria 2, CH-6928 Manno, Switzerland.
| | - Jack A Tuszynski
- Department of Oncology, Department of Physics, University of Alberta, Edmonton, AB T6G 2R3, Canada.
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