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Ma J, Song X, Luo J, Zhao T, Yu H, Peng B, Zhao S. Molecular Dynamics Simulation Insight into Interfacial Stability and Fluidity Properties of Microemulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13636-13645. [PMID: 31560551 DOI: 10.1021/acs.langmuir.9b02325] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Although the interfacial properties of microemulsions have been extensively studied in both experimental and simulation research studies, the molecular mechanisms of stability and fluidity about microemulsion are still poorly understood. Herein, we report a molecular dynamics simulation study to elaborate the motion of an emulsion droplet involving dichain surfactant Aerosol OT (AOT) and its dynamics evolution at the oil-water interface. By varying the concentrations of AOT, we show that the interfacial thickness and emulsification rate display a piecewise change as the interfacial coverage increases and the W/O emulsion is more stable than the O/W one while O/W emulsion presents better fluidity. In addition, the dispersed system combined with water/AOT/n-heptane tends to form a W/O microemulsion instead of an O/W microemulsion due to the structural collapse of the latter. This work provides a molecular understanding of microemulsion interfacial stability and fluidity.
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Affiliation(s)
- Jule Ma
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - Xianyu Song
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - Jianhui Luo
- Research Institute of Petroleum Exploration & Development (RIPED), PetroChina , Beijing 100083 , China
- Key Laboratory of Nano Chemistry (KLNC) , CNPC , Beijing 100083 , China
| | - Teng Zhao
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - Hongping Yu
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
| | - Baoliang Peng
- Research Institute of Petroleum Exploration & Development (RIPED), PetroChina , Beijing 100083 , China
- Key Laboratory of Nano Chemistry (KLNC) , CNPC , Beijing 100083 , China
| | - Shuangliang Zhao
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , China
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Mazzini S, Gargallo R, Musso L, De Santis F, Aviñó A, Scaglioni L, Eritja R, Di Nicola M, Zunino F, Amatulli A, Dallavalle S. Stabilization of c-KIT G-Quadruplex DNA Structures by the RNA Polymerase I Inhibitors BMH-21 and BA-41. Int J Mol Sci 2019; 20:ijms20194927. [PMID: 31590335 PMCID: PMC6801708 DOI: 10.3390/ijms20194927] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 09/26/2019] [Accepted: 10/01/2019] [Indexed: 12/27/2022] Open
Abstract
The stabilization of G-quadruplex DNA structures by small molecules with affinity to oncogene promoters has emerged as a promising anticancer strategy, due to a potential role in gene expression regulation. We explored the ability of BMH-21 (1) and its analogue BA-41 (2) to bind the G-quadruplex structure present in the c-KIT promoter by biophysical methods and molecular modeling. We provide evidence that both compounds interact with the c-KIT 21-mer sequence. The stable monomeric intramolecular parallel G-quadruplex obtained by the mutation of positions 12 and 21 allowed the precise determination of the binding mode by NMR and molecular dynamics studies. Both compounds form a complex characterized by one ligand molecule positioned over the tetrad at the 3′-end, stabilized by an extensive network of π–π interactions. The binding constants (Kb) obtained with fluorescence are similar for both complexes (around 106 M−1). Compound BA-41 (2) showed significant antiproliferative activity against a human lymphoma cell line, SU-DHL4, known to express substantial levels of c-KIT. However, the partial inhibition of c-KIT expression by Western blot analysis suggested that the interaction of compound 2 with the c-KIT promoter is not the primary event and that multiple effects provide a contribution as determinants of biological activity.
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Affiliation(s)
- Stefania Mazzini
- Department of Food, Environmental and Nutritional Sciences (DEFENS), Division of Chemistry and Molecular Biology, University of Milan, via Celoria 2, 20133 Milan, Italy.
| | - Raimundo Gargallo
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí I Franqués 1-11, 08028 Barcelona, Spain.
| | - Loana Musso
- Department of Food, Environmental and Nutritional Sciences (DEFENS), Division of Chemistry and Molecular Biology, University of Milan, via Celoria 2, 20133 Milan, Italy.
| | - Francesca De Santis
- Unit of Immunotherapy and Anticancer innovative Therapeutics, Department of Medical Oncology Fondazione IRCCS, Istituto Nazionale dei Tumori, via Venezian 1, 20133 Milano, Italy.
| | - Anna Aviñó
- Institute for Advanced Chemistry of Catalonia (IQAC), CSIC, Networking Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Jordi Girona 18-26, E-08034 Barcelona, Spain.
| | - Leonardo Scaglioni
- Department of Food, Environmental and Nutritional Sciences (DEFENS), Division of Chemistry and Molecular Biology, University of Milan, via Celoria 2, 20133 Milan, Italy.
| | - Ramon Eritja
- Institute for Advanced Chemistry of Catalonia (IQAC), CSIC, Networking Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Jordi Girona 18-26, E-08034 Barcelona, Spain.
| | - Massimo Di Nicola
- Unit of Immunotherapy and Anticancer innovative Therapeutics, Department of Medical Oncology Fondazione IRCCS, Istituto Nazionale dei Tumori, via Venezian 1, 20133 Milano, Italy.
| | - Franco Zunino
- Unit of Immunotherapy and Anticancer innovative Therapeutics, Department of Medical Oncology Fondazione IRCCS, Istituto Nazionale dei Tumori, via Venezian 1, 20133 Milano, Italy.
| | - Annabella Amatulli
- Department of Food, Environmental and Nutritional Sciences (DEFENS), Division of Chemistry and Molecular Biology, University of Milan, via Celoria 2, 20133 Milan, Italy.
| | - Sabrina Dallavalle
- Department of Food, Environmental and Nutritional Sciences (DEFENS), Division of Chemistry and Molecular Biology, University of Milan, via Celoria 2, 20133 Milan, Italy.
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103
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Santana ACSGV, Nadvorny D, da Rocha Passos TD, de La Roca Soares MF, Soares-Sobrinho JL. Influence of cyclodextrin on posaconazole stability, release and activity: Improve the utility of the drug. J Drug Deliv Sci Technol 2019. [DOI: 10.1016/j.jddst.2019.101153] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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104
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Santos DES, Pontes FJS, Lins RD, Coutinho K, Soares TA. SuAVE: A Tool for Analyzing Curvature-Dependent Properties in Chemical Interfaces. J Chem Inf Model 2019; 60:473-484. [DOI: 10.1021/acs.jcim.9b00569] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Denys E. S. Santos
- Departmento Química Fundamental, Universidade Federal de Pernambuco, 50740-560 Cidade Universitária, Recife, Brazil
| | - Frederico J. S. Pontes
- Departmento Química Fundamental, Universidade Federal de Pernambuco, 50740-560 Cidade Universitária, Recife, Brazil
| | - Roberto D. Lins
- Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, 50740-465 Cidade Universitária, Recife, Brazil
| | - Kaline Coutinho
- Instituto de Física, Universidade de São Paulo, 05508-090 Cidade Universitária, São Paulo, Brazil
| | - Thereza A. Soares
- Departmento Química Fundamental, Universidade Federal de Pernambuco, 50740-560 Cidade Universitária, Recife, Brazil
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105
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Hu Y, Zhao T, Zou L, Wang X, Zhang Y. Molecular dynamics simulations of membrane properties affected by plasma ROS based on the GROMOS force field. Biophys Chem 2019; 253:106214. [PMID: 31272076 DOI: 10.1016/j.bpc.2019.106214] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/25/2019] [Accepted: 06/25/2019] [Indexed: 12/22/2022]
Abstract
Cold atmospheric plasma (CAP) has attracted substantial attention in the field of medical disinfection because its main components, reactive oxygen species (ROS), have a strong destructive effect on various cell components. The cell membrane plays an important role in maintaining proper cellular function by blocking harmful substances such as ROS. In this paper, we used molecular dynamics simulations to study the behaviour of different ROS at the membrane-water interface. The results showed that the cell membrane presented a weak barrier to hydrophobic ROS (O2) but effectively prevented hydrophilic ROS (OH, HO2, H2O2) from entering the cell. The plasma treatment significantly enhanced the permeability of the cell membrane to HO2, while the energetic barrier to other types of ROS changed only slightly. O2 very likely stopped in the centre of the lipid bilayer when crossing the membrane and there attacked the unsaturated region of the phospholipid. Cholesterol was most likely oxidized by HO2, causing a condensing effect that destroyed the integrity and fluidity of the cell membrane. The study also found that large amounts of ROS decreased the thickness of the cell membrane, and the phospholipid arrangement became disordered.
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Affiliation(s)
- Yujia Hu
- School of Electrical Engineering, Shandong University, Ji'nan, Shandong 250061, People's Republic of China
| | - Tong Zhao
- School of Electrical Engineering, Shandong University, Ji'nan, Shandong 250061, People's Republic of China.
| | - Liang Zou
- School of Electrical Engineering, Shandong University, Ji'nan, Shandong 250061, People's Republic of China
| | - Xiaolong Wang
- School of Electrical Engineering, Shandong University, Ji'nan, Shandong 250061, People's Republic of China
| | - Yuantao Zhang
- School of Electrical Engineering, Shandong University, Ji'nan, Shandong 250061, People's Republic of China
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106
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Liu C, Piquemal JP, Ren P. AMOEBA+ Classical Potential for Modeling Molecular Interactions. J Chem Theory Comput 2019; 15:4122-4139. [PMID: 31136175 DOI: 10.1021/acs.jctc.9b00261] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Classical potentials based on isotropic and additive atomic charges have been widely used to model molecules in computers for the past few decades. The crude approximations in the underlying physics are hindering both their accuracy and transferability across chemical and physical environments. Here we present a new classical potential, AMOEBA+, to capture essential intermolecular forces, including permanent electrostatics, repulsion, dispersion, many-body polarization, short-range charge penetration, and charge transfer, by extending the polarizable multipole-based AMOEBA (Atomic Multipole Optimized Energetics for Biomolecular Applications) model. For a set of common organic molecules, we show that AMOEBA+ with general parameters can reproduce both quantum mechanical interactions and energy decompositions according to Symmetry-Adapted Perturbation Theory (SAPT). Additionally, a new water model based on the AMOEBA+ framework captures various liquid-phase properties in molecular dynamics simulations while remaining consistent with SAPT energy decompositions, utilizing both ab initio data and experimental liquid properties. Our results demonstrate that it is possible to improve the physical basis of classical force fields to advance their accuracy and general applicability.
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Affiliation(s)
- Chengwen Liu
- Department of Biomedical Engineering , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Jean-Philip Piquemal
- Department of Biomedical Engineering , The University of Texas at Austin , Austin , Texas 78712 , United States.,Laboratoire de Chimie Théorique , Sorbonne Université, UMR7616 CNRS , Paris 75252 , France.,Institut Universitaire de France , Paris Cedex 05, 75005 , France
| | - Pengyu Ren
- Department of Biomedical Engineering , The University of Texas at Austin , Austin , Texas 78712 , United States
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107
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Oliveira ACDJ, Araújo ARD, Quelemes PV, Nadvorny D, Soares-Sobrinho JL, Leite JRSDA, da Silva-Filho EC, Silva DAD. Solvent-free production of phthalated cashew gum for green synthesis of antimicrobial silver nanoparticles. Carbohydr Polym 2019; 213:176-183. [DOI: 10.1016/j.carbpol.2019.02.033] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 02/05/2019] [Accepted: 02/11/2019] [Indexed: 02/03/2023]
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108
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Zhao F, Wang JL, Ming HY, Zhang YN, Dun YQ, Zhang JH, Song YB. Insights into the binding mode and functional components of the analgesic-antitumour peptide from Buthus martensii Karsch to human voltage-gated sodium channel 1.7 based on dynamic simulation analysis. J Biomol Struct Dyn 2019; 38:1868-1879. [PMID: 31099313 DOI: 10.1080/07391102.2019.1620126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Voltage-gated sodium (Nav) channels are transmembrane proteins composed of four homologous domains (DI-DIV) that play important roles in membrane excitability in neurons and muscles. Analgesic-antitumour peptide (AGAP) is a neurotoxin from the scorpion Buthus martensii Karsch, and has been shown to exert analgesic effect by binding on site 4 of human Nav1.7 (hNav1.7). Mechanistic details about this binding, however, remain unclear. To address this issue, we compared the binding modes of AGAP/AGAPW38G/AGAPW38F and the hNav1.7 voltage-sensing domain on DII (VSD2hNav1.7) using homology modeling, molecular docking, molecular dynamics simulation and steered molecular dynamics. Results revealed the key role of tryptophan at position 38 on the binding of AGAP to VSD2hNav1.7. Pivotal roles are played also by residues on the β-turn and negatively charged residues at the C-terminal. We further show that electrostatic interaction is the main contributor to the binding free energy of the complex. Agreement between our computational simulation findings and prior experimental data supports the accuracy of the described mechanism. Accordingly, these results can provide valuable information for designing potent toxin analgesics targeting hNav1.7 with high affinity.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Fan Zhao
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Jin-Long Wang
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Hong-Yan Ming
- The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Ya-Nan Zhang
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Ying-Qiao Dun
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Jing-Hai Zhang
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Yong-Bo Song
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
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109
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Júnior JJS, Soares TA, Pol-Fachin L, Machado DC, Rusu VH, Aguiar JP, Rodrigues CG. Alpha-hemolysin nanopore allows discrimination of the microcystins variants. RSC Adv 2019; 9:14683-14691. [PMID: 35516306 PMCID: PMC9064141 DOI: 10.1039/c8ra10384d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/01/2019] [Indexed: 01/20/2023] Open
Abstract
Microcystins (MCs) are a class of cyclic heptapeptides with more than 100 variants produced by cyanobacteria present in surface waters. MCs are potent hepatotoxic agents responsible for fatal poisoning in animals and humans. Several techniques are employed in the detection of MCs, however, there is a shortage of methods capable of discriminating variants of MCs. In this work we demonstrate that the α-hemolysin (αHL) nanopore can detect and discriminate the variants (LR, YR and RR) of MCs in aqueous solution. The discrimination process is based on the analysis of the residence times of each variant of MCs within the unitary nanopore, as well as, on the amplitudes of the blockages in the ionic current flowing through it. Simulations of molecular dynamics and calculation of the electrostatic potential revealed that the variants of MCs present different charge distribution and correlated with the three patterns on the amplitudes of the blockages in the ionic current. Additionally, molecular docking analysis indicates different patterns of interaction of the variants of MCs with two specific regions of the nanopore. We conclude that αHL nanopore can discriminate variants of microcystins by a mechanism based mainly on electrostatic interaction. Finally, we propose the use of nanopore-based technology as a promising method for analyzing microcystins in aqueous solutions.
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Affiliation(s)
- Janilson J S Júnior
- Departamento de Biofísica e Radiobiologia, Universidade Federal de Pernambuco Avenida Prof. Moraes Rego, s/n, Cidade Universitária Recife Pernambuco 50670-901 Brazil +55 81 2126 8560 +55 81 2126 8535
- Programa de Pós-graduação em Inovação Terapêutica, Universidade Federal de Pernambuco Brazil
| | - Thereza A Soares
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitária 50740-560 Recife PE Brazil
| | - Laércio Pol-Fachin
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitária 50740-560 Recife PE Brazil
- Centro de Pesquisas Aggeu Magalhães Fundação Oswaldo Cruz, Cidade Universitária 50740-465 Recife PE Brazil
| | - Dijanah C Machado
- Departamento de Biofísica e Radiobiologia, Universidade Federal de Pernambuco Avenida Prof. Moraes Rego, s/n, Cidade Universitária Recife Pernambuco 50670-901 Brazil +55 81 2126 8560 +55 81 2126 8535
| | - Victor H Rusu
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitária 50740-560 Recife PE Brazil
| | - Juliana P Aguiar
- Departamento de Biofísica e Radiobiologia, Universidade Federal de Pernambuco Avenida Prof. Moraes Rego, s/n, Cidade Universitária Recife Pernambuco 50670-901 Brazil +55 81 2126 8560 +55 81 2126 8535
- Programa de Pós-graduação em Inovação Terapêutica, Universidade Federal de Pernambuco Brazil
| | - Cláudio G Rodrigues
- Departamento de Biofísica e Radiobiologia, Universidade Federal de Pernambuco Avenida Prof. Moraes Rego, s/n, Cidade Universitária Recife Pernambuco 50670-901 Brazil +55 81 2126 8560 +55 81 2126 8535
- Programa de Pós-graduação em Inovação Terapêutica, Universidade Federal de Pernambuco Brazil
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110
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Itliong JN, Villagracia ARC, Moreno JLV, Rojas KIM, Bernardo GPO, David MY, Manrique RB, Ubando AT, Culaba AB, Padama AAB, Ong HL, Chang JS, Chen WH, Kasai H, Arboleda NB. Investigation of reverse ionic diffusion in forward-osmosis-aided dewatering of microalgae: A molecular dynamics study. BIORESOURCE TECHNOLOGY 2019; 279:181-188. [PMID: 30731357 DOI: 10.1016/j.biortech.2019.01.109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 05/14/2023]
Abstract
This study aimed to investigate the transport mechanisms of ions during forward-osmosis-driven (FO-driven) dewatering of microalgae using molecular dynamics (MD) simulations. The dynamical and structural properties of ions in FO systems of varying NaCl or MgCl2 draw solution (DS) concentrations were calculated and correlated. Results indicate that FO systems with higher DS concentration caused ions to have lower hydration numbers and higher coordination numbers leading to lower diffusion coefficients. The higher hydration number of Mg2+ ions resulted in significantly lower ionic permeability as compared to Na+ ions at all concentrations (p = 0.002). The simulations also revealed that higher DS concentrations led to higher accumulation of ions in the membrane. This study provides insights on the proper selection of DS for FO systems.
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Affiliation(s)
- Jester N Itliong
- Physics Department, College of Science, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines; Applied Physics Department, Eulogio "Amang" Rodriguez Institute of Science and Technology, Nagtahan, Sampaloc, Manila, Philippines.
| | - Al Rey C Villagracia
- Physics Department, College of Science, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines; Advanced Nanomaterials Investigation and Molecular Simulations (ANIMoS) Research Unit, CENSER, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines; Department of Agricultural and Biosystems Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - Joaquin Lorenzo V Moreno
- Physics Department, College of Science, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines; Advanced Nanomaterials Investigation and Molecular Simulations (ANIMoS) Research Unit, CENSER, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines
| | - Kurt Irvin M Rojas
- Physics Department, College of Science, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines
| | - Gian Paolo O Bernardo
- Physics Department, College of Science, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines
| | - Melanie Y David
- Physics Department, College of Science, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines; Advanced Nanomaterials Investigation and Molecular Simulations (ANIMoS) Research Unit, CENSER, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines
| | - Robby B Manrique
- Mechanical Engineering Department, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines
| | - Aristotle T Ubando
- Mechanical Engineering Department, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines
| | - Alvin B Culaba
- Mechanical Engineering Department, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines
| | - Allan Abraham B Padama
- Institute of Mathematical Sciences and Physics, University of the Philippines, Los Baños, Laguna, Philippines
| | - Hui Lin Ong
- School of Materials Engineering, Universiti Malaysia Perlis, Kompleks Pusat Pengajian Jejawi 2, 02600 Arau, Perlis, Malaysia; Centre of Excellence for Biomass Utilization, Universiti Malaysia Perlis, Lot 17, Kompleks Pusat Pengajian Jejawi 2, 02600 Jejawi, Arau, Malaysia; Taiwan-Malaysia Innovation Center for Clean Water and Sustainable Energy (WISE Center), Lot 17, Kompleks Pusat Pengajian Jejawi 2, 02600 Jejawi, Arau, Malaysia
| | - Jo-Shu Chang
- Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan; Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan; College of Engineering, Tunghai University, Taichung 407, Taiwan
| | - Wei-Hsin Chen
- Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan; Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan
| | - Hideaki Kasai
- National Institute of Technology, 679-3 Nishioka, Uozumi-cho, Akashi-City, Hyogo-Prefecture 674-8501, Japan
| | - Nelson B Arboleda
- Physics Department, College of Science, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines; Advanced Nanomaterials Investigation and Molecular Simulations (ANIMoS) Research Unit, CENSER, De La Salle University, 2401 Taft Ave., Malate, 1004 Manila, Philippines; De La Salle University - Science and Technology Complex, Biñan, Laguna, Philippines
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111
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Thallmair S, Vainikka PA, Marrink SJ. Lipid Fingerprints and Cofactor Dynamics of Light-Harvesting Complex II in Different Membranes. Biophys J 2019; 116:1446-1455. [PMID: 30954210 PMCID: PMC6486485 DOI: 10.1016/j.bpj.2019.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/22/2019] [Accepted: 03/12/2019] [Indexed: 11/29/2022] Open
Abstract
Plant light-harvesting complex II (LHCII) is the key antenna complex for plant photosynthesis. We present coarse-grained molecular dynamics simulations of monomeric and trimeric LHCII in a realistic thylakoid membrane environment based on the Martini force field. The coarse-grained protein model has been optimized with respect to atomistic reference simulations. Our simulations provide detailed insights in the thylakoid lipid fingerprint of LHCII which compares well with experimental data from membrane protein purification. Comparing the monomer and trimeric LHCII reveals a stabilizing effect of trimerization on the chromophores as well as the protein. Moreover, the average chromophore distance shortens in the trimer leading to stronger excitonic couplings. When changing the native thylakoid environment to a model membrane the protein flexibility remains constant, whereas the chromophore flexibility is reduced. Overall, the presented LHCII model lays the foundation to investigate the μs dynamics of this key antenna protein of plants.
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Affiliation(s)
- Sebastian Thallmair
- Groningen Biomolecular Sciences and Biotechnology Institute and The Zernike Institute for Advanced Material, University of Groningen, Groningen, The Netherlands.
| | - Petteri A Vainikka
- Groningen Biomolecular Sciences and Biotechnology Institute and The Zernike Institute for Advanced Material, University of Groningen, Groningen, The Netherlands; Department of Chemistry, University of Turku, Turku, Finland
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and The Zernike Institute for Advanced Material, University of Groningen, Groningen, The Netherlands.
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112
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Santos DES, Li D, Ramstedt M, Gautrot JE, Soares TA. Conformational Dynamics and Responsiveness of Weak and Strong Polyelectrolyte Brushes: Atomistic Simulations of Poly(dimethyl aminoethyl methacrylate) and Poly(2-(methacryloyloxy)ethyl trimethylammonium chloride). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5037-5049. [PMID: 30869897 DOI: 10.1021/acs.langmuir.8b04268] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The complex solution behavior of polymer brushes is key to control their properties, including for biomedical applications and catalysis. The swelling behavior of poly(dimethyl aminoethyl methacrylate) (PDMAEMA) and poly(2-(methacryloyloxy)ethyl trimethylammonium chloride) (PMETAC) in response to changes in pH, solvent, and salt types has been investigated using atomistic molecular dynamics simulations. PDMAEMA and PMETAC have been selected as canonical models for weak and strong polyelectrolytes whose complex conformational behavior is particularly challenging for the development and validation of atomistic models. The GROMOS-derived atomic parameters reproduce the experimental swelling coefficients obtained from ellipsometry measurements for brushes of 5-15 nm thickness. The present atomistic models capture the protonated morphology of PDMAEMA, the swollen and collapsed conformations of PDMAEMA and PMETAC in good and bad solvents, and the salt-selective response of PMETAC. The modular nature of the molecular models allows for the simple extension of atomic parameters to a variety of polymers or copolymers.
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Affiliation(s)
- Denys E S Santos
- Departamento de Química Fundamental , Universidade Federal de Pernambuco , Cidade Universitária, 50670-901 Recife , Brazil
| | | | | | | | - Thereza A Soares
- Departamento de Química Fundamental , Universidade Federal de Pernambuco , Cidade Universitária, 50670-901 Recife , Brazil
- Department of Chemistry , Umeå University , 90187 Umeå , Sweden
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113
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Messina GML, Di Napoli B, De Zotti M, Mazzuca C, Formaggio F, Palleschi A, Marletta G. Molecular Sponge: pH-Driven Reversible Squeezing of Stimuli-Sensitive Peptide Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:4813-4824. [PMID: 30864802 DOI: 10.1021/acs.langmuir.8b03895] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The cyclic change of structure, thickness, and density, with pH switching from acidic (pH = 3) to basic (pH = 11) condition, has been revealed for chemisorbed monolayers of the peptide Lipo-Aib-Lys-Leu-Aib-Lys-Lys-Leu-Aib-Lys-Ile-Lol, a trichogin GA IV-analogue carrying Lys residues instead of Gly ones at positions 2, 5, 6, and 9, while a homologous peptide not containing Lys residues does not show any response to pH changes. Experimental and theoretical results, obtained by means of quartz crystal microbalance with dissipation monitoring, surface plasmon resonance, nanoplasmonic sensing technique, Fourier transform infrared-reflection attenuated spectroscopy and dynamic force spectroscopy, and molecular dynamics simulations provide detailed information on the overall monolayer structure changes with pH, including the analysis of the intra- and interchain peptide dynamics, the structure of the peptide layer/water/solid interface, as well as the position and role of solvation and nonsolvation water. The observed stimuli-responsive behavior of L1 peptide monolayers is accounted in terms of the occurrence of a pH-induced wetting/dewetting process, due to the pH-induced switching of the hydrophilic character of charged lysine groups to hydrophobic one of the same uncharged groups, along the peptide chain. This behavior in turn promotes the collective change of the aggregation state of the peptide chains. The present results may pave the way to critically reexamine the mechanism of stimuli-responsive systems.
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Affiliation(s)
- Grazia M L Messina
- Laboratory for Molecular Surfaces and Nanotechnology (LAMSUN), Department of Chemical Sciences , University of Catania and CSGI , Viale Andrea Doria 6 , 95125 Catania , Italy
| | - Benedetta Di Napoli
- Department of Chemical Sciences and Technologies , University of Roma Tor Vergata , Via della Ricerca Scientifica , 00133 Roma , Italy
| | - Marta De Zotti
- CB Padova Unit, CNR, Department of Chemistry , University of Padova , 35131 Padova , Italy
| | - Claudia Mazzuca
- Department of Chemical Sciences and Technologies , University of Roma Tor Vergata , Via della Ricerca Scientifica , 00133 Roma , Italy
| | - Fernando Formaggio
- CB Padova Unit, CNR, Department of Chemistry , University of Padova , 35131 Padova , Italy
| | - Antonio Palleschi
- Department of Chemical Sciences and Technologies , University of Roma Tor Vergata , Via della Ricerca Scientifica , 00133 Roma , Italy
| | - Giovanni Marletta
- Laboratory for Molecular Surfaces and Nanotechnology (LAMSUN), Department of Chemical Sciences , University of Catania and CSGI , Viale Andrea Doria 6 , 95125 Catania , Italy
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114
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Yan H, Wang Y, Zhang L, Li G, Wei X, Liu C. Molecular dynamics simulation of spherical-to -threadlike micelle transition in a cationic surfactant solution. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1601190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Hui Yan
- College of Pharmacy & College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, People’s Republic of China
| | - Yue Wang
- College of Pharmacy & College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, People’s Republic of China
| | - Luge Zhang
- College of Pharmacy & College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, People’s Republic of China
| | - Guangyong Li
- College of Pharmacy & College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, People’s Republic of China
| | - Xilian Wei
- College of Pharmacy & College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, People’s Republic of China
| | - Chongfeng Liu
- Department of Pharmacy, Liaocheng City People’s Hospital, Liaocheng, People’s Republic of China
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115
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Fortes-Dias CL, Fernandes CAH, Ortolani PL, Campos PC, Melo LA, Felicori LF, Fontes MRM. Identification, description and structural analysis of beta phospholipase A 2 inhibitors (sbβPLIs) from Latin American pit vipers indicate a binding site region for basic snake venom phospholipases A 2. Toxicon X 2019; 2:100009. [PMID: 32550566 PMCID: PMC7286088 DOI: 10.1016/j.toxcx.2019.100009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 02/04/2019] [Accepted: 02/13/2019] [Indexed: 11/17/2022] Open
Abstract
Several snake species possess, in their circulating blood, endogenous PLA2 inhibitors (sbPLIs) with the primary function of natural protection against toxic enzymes from homologous and heterologous venoms. Among the three structural classes of sbPLIs – named α, β, and γ − the β class (sbβPLIs) is the least known with only four identified sequences, so far. The last class of inhibitors encompass molecules with leucine rich repeats (LRRs) motifs containing repeating amino acid segments. In the present study, we identified and characterized putative sbβPLIs from the liver and venom glands of six Latin American pit vipers belonging to Bothrops and Crotalus genera. The inhibitor from Crotalus durissus terrificus snakes (CdtsbβPLI) was chosen as a reference for the construction of the first in silico structural model for this class of inhibitors, using molecular modeling and molecular dynamics simulations. Detailed analyses of the electrostatic surface of the CdtsbβPLI model and protein-protein docking with crotoxin B from homologous venoms predict the interacting surface between these proteins. Transcripts of phospholipases A2 inhibitors from the β-class (sbβPLIs) were identified in Latin American pit vipers. Structural features of sbβPLIs were compared and discussed, including their characteristic leucine-rich repeats (LRRs). One sbβPLI (CdtsbβPLI) was chosen for the in silico construction of the first structural model of a sbβPLI. A possible mechanism of interaction between sbβPLIs and basic snake venom PLA2s was suggested. Docking predictions between CdtsbβPLI and crotoxin B highlighted the amino acids residues at the interaction surfaces.
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Affiliation(s)
- Consuelo Latorre Fortes-Dias
- Serviço de Enzimologia, Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brazil
| | - Carlos Alexandre H Fernandes
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil.,Departamento de Genética, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Paula Ladeira Ortolani
- Serviço de Enzimologia, Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brazil
| | - Patrícia Cota Campos
- Serviço de Enzimologia, Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brazil
| | - L A Melo
- Serviço de Enzimologia, Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brazil
| | - Liza Figueiredo Felicori
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Marcos Roberto M Fontes
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
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116
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Dolai S, Barrio J, Peng G, Grafmüller A, Shalom M. Tailoring carbon nitride properties and photoactivity by interfacial engineering of hydrogen-bonded frameworks. NANOSCALE 2019; 11:5564-5570. [PMID: 30860536 DOI: 10.1039/c9nr00711c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The rational synthesis of carbon nitride materials, ranging from polymeric carbon nitride to nitrogen-doped carbon, by supramolecular preorganization of their monomers is a powerful tool for the design of their morphology and photophysical and catalytic activities. Here we show a new facile and scalable approach for the synthesis of ordered CN materials with excellent photoactivity, which consists of supramolecular interfacial preorganization of CN monomers at the interface of two non-miscible solvents. Molecular dynamic simulations supported by experimental results reveal that an appropriate choice of monomers and solvents leads to the formation of a supramolecular assembly solely at the interface of the solvents. As a proof of concept, we show that the properties of the CN materials after thermal condensation can be tuned by adding an additional monomer to one solvent only. The advantages of the new method are demonstrated here through the tunable morphologies and surface area, the formation of new electronic junctions and high activity as a photocatalyst for hydrogen evolution and pollutant degradation of the CN materials.
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Affiliation(s)
- Susmita Dolai
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
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117
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Shearer J, Jefferies D, Khalid S. Outer Membrane Proteins OmpA, FhuA, OmpF, EstA, BtuB, and OmpX Have Unique Lipopolysaccharide Fingerprints. J Chem Theory Comput 2019; 15:2608-2619. [PMID: 30848905 DOI: 10.1021/acs.jctc.8b01059] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The outer membrane of Gram-negative bacteria has a highly complex asymmetrical architecture, containing a mixture of phospholipids in the inner leaflet and almost exclusively lipopolysaccharide (LPS) molecules in the outer leaflet. In E. coli, the outer membrane contains a wide range of proteins with a β barrel architecture, that vary in size from the smallest having eight strands to larger barrels composed of 22 strands. Here we report coarse-grained molecular dynamics simulations of six proteins from the E. coli outer membrane OmpA, OmpX, BtuB, FhuA, OmpF, and EstA in a range of membrane environments, which are representative of the in vivo conditions for different strains of E. coli. We show that each protein has a unique pattern of interaction with the surrounding membrane, which is influenced by the composition of the protein, the level of LPS in the outer leaflet, and the differing mobilities of the lipids in the two leaflets of the membrane. Overall we present analyses from over 200 μs of simulation for each protein.
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Affiliation(s)
- Jonathan Shearer
- School of Chemistry , University of Southampton, Highfield , Southampton , SO17 1BJ United Kingdom
| | - Damien Jefferies
- School of Chemistry , University of Southampton, Highfield , Southampton , SO17 1BJ United Kingdom
| | - Syma Khalid
- School of Chemistry , University of Southampton, Highfield , Southampton , SO17 1BJ United Kingdom
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118
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Mechanism of glucocerebrosidase activation and dysfunction in Gaucher disease unraveled by molecular dynamics and deep learning. Proc Natl Acad Sci U S A 2019; 116:5086-5095. [PMID: 30808805 DOI: 10.1073/pnas.1818411116] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The lysosomal enzyme glucocerebrosidase-1 (GCase) catalyzes the cleavage of a major glycolipid glucosylceramide into glucose and ceramide. The absence of fully functional GCase leads to the accumulation of its lipid substrates in lysosomes, causing Gaucher disease, an autosomal recessive disorder that displays profound genotype-phenotype nonconcordance. More than 250 disease-causing mutations in GBA1, the gene encoding GCase, have been discovered, although only one of these, N370S, causes 70% of disease. Here, we have used a knowledge-based docking protocol that considers experimental data of protein-protein binding to generate a complex between GCase and its known facilitator protein saposin C (SAPC). Multiscale molecular-dynamics simulations were used to study lipid self-assembly, membrane insertion, and the dynamics of the interactions between different components of the complex. Deep learning was applied to propose a model that explains the mechanism of GCase activation, which requires SAPC. Notably, we find that conformational changes in the loops at the entrance of the substrate-binding site are stabilized by direct interactions with SAPC and that the loss of such interactions induced by N370S and another common mutation, L444P, result in destabilization of the complex and reduced GCase activation. Our findings provide an atomistic-level explanation for GCase activation and the precise mechanism through which N370S and L444P cause Gaucher disease.
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119
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Liu X, Li Y, Tian S, Yan H. Reversible Solubilization of Pyrene by a Gas Switchable Surfactant Investigated by Molecular Dynamics Simulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:15445-15454. [PMID: 30475632 DOI: 10.1021/acs.langmuir.8b03310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The reversible solubilization behavior of pyrene by a CO2/N2 switchable surfactant (named N'-dodecyl- N, N-dimethylacetamidinium bicarbonate (DDAB)) was investigated with molecular dynamics (MD) simulations. We first individually simulated the aggregation of the inactive surfactant N'-dodecyl- N, N-dimethylacetamidines (DDA) and effective surfactant DDAB in water. Detailed structural properties analysis showed that DDAB molecules aggregated into a micelle, while the aggregation of DDA molecules was considered to be an oil droplet that was separated from the water phase. MD simulations revealed that pyrene molecule was solubilized in the interior hydrophobic region of the micelle as expected. Pyrene was adsorbed on the surface of the oil droplet which is due to the dense packing of DDA molecules inside the oil droplet. The simulated release process showed that the solubilized pyrene in the interior was squeezed out when the micelle was changed to an oil droplet. Reduced density gradient (RDG) function was used to study the weak interactions and explore the molecular driving force behind the reversible solubilization. The results demonstrated that repulsion effects of water molecules on the DDA headgroups play an important role on the pyrene release. Because of the persistent molecular motion of DDA molecules into the droplet center, pyrene was finally repelled out of the oil droplet. Our study provided a molecular mechanism into the reversible solubilization of a gas-controlled switchable surfactant. This is expected to be useful for surfactant-enhanced remediation (SER) experiments.
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Affiliation(s)
- Xiangliang Liu
- Faculty of Environmental Science and Engineering , Kunming University of Science and Technology , Kunming 650500 , China
| | - Yingjie Li
- Faculty of Environmental Science and Engineering , Kunming University of Science and Technology , Kunming 650500 , China
| | - Senlin Tian
- Faculty of Environmental Science and Engineering , Kunming University of Science and Technology , Kunming 650500 , China
| | - Hui Yan
- School of Pharmacy , Liaocheng University , Liaocheng 252059 , China
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120
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Wu X, Xu G, Li X, Xu W, Li Q, Liu W, Kirby KA, Loh ML, Li J, Sarafianos SG, Qu CK. Small Molecule Inhibitor that Stabilizes the Autoinhibited Conformation of the Oncogenic Tyrosine Phosphatase SHP2. J Med Chem 2018; 62:1125-1137. [PMID: 30457860 DOI: 10.1021/acs.jmedchem.8b00513] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Genetic mutations in the phosphatase PTPN11 (SHP2) are associated with childhood leukemias. These mutations cause hyperactivation of SHP2 due to the disruption of the autoinhibitory conformation. By targeting the activation-associated protein conformational change, we have identified an SHP2 inhibitor ( E)-1-(1-(5-(3-(2,4-dichlorophenyl)acryloyl)-2-ethoxy-4-hydroxybenzyl)-1,2,5,6-tetrahydropyridin-3-yl)-1 H-benzo[ d]imidazol-2(3 H)-one (LY6, 1) using computer-aided drug design database screening combined with cell-based assays. This compound inhibited SHP2 with an IC50 value of 9.8 μM, 7-fold more selective for SHP2 than the highly related SHP1. Fluorescence titration, thermal shift, and microscale thermophoresis quantitative binding assays confirmed its direct binding to SHP2. This compound was further verified to effectively inhibit SHP2-mediated cell signaling and proliferation. Furthermore, mouse and patient leukemia cells with PTPN11 activating mutations were more sensitive to this inhibitor than wild-type cells. This small molecule SHP2 inhibitor has a potential to serve as a lead compound for further optimization studies to develop novel anti-SHP2 therapeutic agents.
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Affiliation(s)
- Xiaoqin Wu
- Department of Pediatrics, Division of Hematology/Oncology, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta , Emory University School of Medicine , Atlanta , Georgia 30322 , United States
| | - Gang Xu
- Department of Medicine, Division of Hematology and Oncology, Case Comprehensive Cancer Center , Case Western Reserve University , Cleveland , Ohio 44106 , United States
| | - Xiaobo Li
- Department of Pediatrics, Division of Hematology/Oncology, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta , Emory University School of Medicine , Atlanta , Georgia 30322 , United States.,Department of Medicine, Division of Hematology and Oncology, Case Comprehensive Cancer Center , Case Western Reserve University , Cleveland , Ohio 44106 , United States
| | - Weiren Xu
- Department of Medicine, Division of Hematology and Oncology, Case Comprehensive Cancer Center , Case Western Reserve University , Cleveland , Ohio 44106 , United States
| | - Qianjin Li
- Department of Pediatrics, Division of Hematology/Oncology, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta , Emory University School of Medicine , Atlanta , Georgia 30322 , United States
| | - Wei Liu
- Department of Medicine, Division of Hematology and Oncology, Case Comprehensive Cancer Center , Case Western Reserve University , Cleveland , Ohio 44106 , United States
| | - Karen A Kirby
- Department of Pediatrics, Laboratory of Biochemical Pharmacology , Emory University School of Medicine , Atlanta , Georgia 30322 , United States
| | - Mignon L Loh
- Department of Pediatrics, Division of Pediatric Hematology-Oncology , University of California, San Francisco , San Francisco , California 94122 , United States
| | - Jun Li
- School of Pharmacy , Anhui Medical University , Hefei 230032 , China
| | - Stefan G Sarafianos
- Department of Pediatrics, Laboratory of Biochemical Pharmacology , Emory University School of Medicine , Atlanta , Georgia 30322 , United States
| | - Cheng-Kui Qu
- Department of Pediatrics, Division of Hematology/Oncology, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta , Emory University School of Medicine , Atlanta , Georgia 30322 , United States.,Department of Medicine, Division of Hematology and Oncology, Case Comprehensive Cancer Center , Case Western Reserve University , Cleveland , Ohio 44106 , United States
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121
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Sindhu T, Venkatesan T, Prabhu D, Jeyakanthan J, Gracy GR, Jalali SK, Rai A. Insecticide-resistance mechanism of Plutella xylostella (L.) associated with amino acid substitutions in acetylcholinesterase-1: A molecular docking and molecular dynamics investigation. Comput Biol Chem 2018; 77:240-250. [DOI: 10.1016/j.compbiolchem.2018.09.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/01/2018] [Accepted: 09/03/2018] [Indexed: 01/22/2023]
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122
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Larin SV, Nazarychev VM, Dobrovskiy AY, Lyulin AV, Lyulin SV. Structural Ordering in SWCNT-Polyimide Nanocomposites and Its Influence on Their Mechanical Properties. Polymers (Basel) 2018; 10:E1245. [PMID: 30961170 PMCID: PMC6401868 DOI: 10.3390/polym10111245] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 11/06/2018] [Accepted: 11/07/2018] [Indexed: 12/01/2022] Open
Abstract
Using fully-atomistic models, tens-microseconds-long molecular-dynamic modelling was carried out for the first time to simulate the kinetics of polyimides ordering induced by the presence of single-walled carbon nanotube (SWCNT) nanofillers. Three polyimides (PI) were considered with different dianhydride fragments, namely 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,3',3,4'-biphenyltetracarboxylic dianhydride (aBPDA), and 3,3',4,4'-oxidiphthalic dianhydride (ODPA) and same diamine 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene (diamine P3). Both crystallizable PI BPDA-P3 and two amorphous polyimides ODPA-P3 and aBPDA-P3 reinforced by SWCNTs were studied. The structural properties of the nanocomposites at temperature close to the bulk polymer melting point were studied. The mechanical properties were determined for the nanocomposites cooled down to the glassy state. It was found that the SWCNT nanofiller initiates' structural ordering not only in the crystallizable BPDA-P3 but also in the amorphous ODPA-P3 samples were in agreement with previously obtained experimental results. Two stages of the structural ordering were detected in the presence of SWCNTs, namely the orientation of the planar moieties followed by the elongation of whole polymer chains. The first type of local ordering was observed on the microsecond time scale and did not lead to the change of the mechanical properties of a polymer binder in considered nanocomposites. At the end of the second stage, both BPDA-P3 and ODPA-P3 PI chains extended completely along the SWCNT surface, which in turn led to enhanced mechanical characteristics in their glassy state.
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Affiliation(s)
- Sergey V Larin
- Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg 199004, Russia.
| | - Victor M Nazarychev
- Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg 199004, Russia.
| | - Alexey Yu Dobrovskiy
- Faculty of Physics, St. Petersburg State University, Petrodvorets, St. Petersburg 198504, Russia.
| | - Alexey V Lyulin
- Theory of Polymers and Soft Matter Group and Center for Computational Energy Research, Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven, The Netherlands.
| | - Sergey V Lyulin
- Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg 199004, Russia.
- Faculty of Physics, St. Petersburg State University, Petrodvorets, St. Petersburg 198504, Russia.
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123
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Silva TFD, Vila-Viçosa D, Reis PBPS, Victor BL, Diem M, Oostenbrink C, Machuqueiro M. The Impact of Using Single Atomistic Long-Range Cutoff Schemes with the GROMOS 54A7 Force Field. J Chem Theory Comput 2018; 14:5823-5833. [DOI: 10.1021/acs.jctc.8b00758] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Tomás F. D. Silva
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Diogo Vila-Viçosa
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Pedro B. P. S. Reis
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Bruno L. Victor
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Matthias Diem
- Department of Material Sciences and Process Engineering, Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences Vienna, Muthgasse 18, A-1190 Vienna, Austria
| | - Chris Oostenbrink
- Department of Material Sciences and Process Engineering, Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences Vienna, Muthgasse 18, A-1190 Vienna, Austria
| | - Miguel Machuqueiro
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
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124
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Thompson HN, Thompson CE, Andrade Caceres R, Dardenne LE, Netz PA, Stassen H. Prion protein conversion triggered by acidic condition: a molecular dynamics study through different force fields. J Comput Chem 2018; 39:2000-2011. [DOI: 10.1002/jcc.25380] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/15/2018] [Accepted: 05/26/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Helen Nathalia Thompson
- Departamento de Físico-Química, Instituto de Química; Universidade Federal do Rio Grande do Sul; 91501-970 Porto Alegre Rio Grande do Sul Brazil
| | - Claudia Elizabeth Thompson
- Departamento de Farmacociências; Universidade Federal de Ciências da Saúde de Porto Alegre; 90050-170 Porto Alegre Rio Grande do Sul Brazil
| | - Rafael Andrade Caceres
- Departamento de Farmacociências; Universidade Federal de Ciências da Saúde de Porto Alegre; 90050-170 Porto Alegre Rio Grande do Sul Brazil
| | | | - Paulo Augusto Netz
- Departamento de Físico-Química, Instituto de Química; Universidade Federal do Rio Grande do Sul; 91501-970 Porto Alegre Rio Grande do Sul Brazil
| | - Hubert Stassen
- Departamento de Físico-Química, Instituto de Química; Universidade Federal do Rio Grande do Sul; 91501-970 Porto Alegre Rio Grande do Sul Brazil
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125
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Haynes T, Smith IPS, Wallace EJ, Trick JL, Sansom MSP, Khalid S. Electric-Field-Driven Translocation of ssDNA through Hydrophobic Nanopores. ACS NANO 2018; 12:8208-8213. [PMID: 29985578 DOI: 10.1021/acsnano.8b03365] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The accurate sequencing of DNA using nanopores requires control over the speed of DNA translocation through the pores and also of the DNA conformation. Our studies show that ssDNA translocates through hourglass-shaped pores with hydrophobic constriction regions when an electric field is applied. The constriction provides a barrier to translocation and thereby slows down DNA movement through the pore compared with pores without the constriction. We show that ssDNA moves through these hydrophobic pores in an extended conformation and therefore does not form undesirable secondary structures that may affect the accuracy of partial current blockages for DNA sequencing.
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Affiliation(s)
- Taylor Haynes
- School of Chemistry , University of Southampton , Highfield Campus , Southampton SO17 1BJ , United Kingdom
| | - Iain P S Smith
- School of Chemistry , University of Southampton , Highfield Campus , Southampton SO17 1BJ , United Kingdom
| | - E Jayne Wallace
- Oxford Nanopore Technologies, Ltd. , Oxford Science Park OX4 4DQ , United Kingdom
| | - Jemma L Trick
- Department of Physics , King's College London , London WC2R 2LS , United Kingdom
| | - Mark S P Sansom
- Department of Biochemistry , University of Oxford , South Parks Road , Oxford OX1 3QU , United Kingdom
| | - Syma Khalid
- School of Chemistry , University of Southampton , Highfield Campus , Southampton SO17 1BJ , United Kingdom
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127
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Yahyaei M, Mehrnejad F, Naderi-manesh H, Rezayan AH. Protein adsorption onto polysaccharides: Comparison of chitosan and chitin polymers. Carbohydr Polym 2018; 191:191-197. [DOI: 10.1016/j.carbpol.2018.03.034] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/25/2017] [Accepted: 03/13/2018] [Indexed: 12/21/2022]
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128
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Lau QY, Li J, Sani MA, Sinha S, Li Y, Ng FM, Kang C, Bhattacharjya S, Separovic F, Verma C, Chia CSB. Elucidating the bactericidal mechanism of action of the linear antimicrobial tetrapeptide BRBR-NH 2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1517-1527. [PMID: 29758185 DOI: 10.1016/j.bbamem.2018.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 12/22/2022]
Abstract
Linear antimicrobial peptides, with their rapid bactericidal mode of action, are well-suited for development as topical antibacterial drugs. We recently designed a synthetic linear 4-residue peptide, BRBR-NH2, with potent bactericidal activity against Staphylococcus aureus (MIC 6.25 μM), the main causative pathogen of human skin infections with an unknown mechanism of action. Herein, we describe a series of experiments conducted to gain further insights into its mechanism of action involving electron microscopy, artificial membrane dye leakage, solution- and solid-state NMR spectroscopy followed by molecular dynamics simulations. Experimental results point towards a SMART (Soft Membranes Adapt and Respond, also Transiently) mechanism of action, suggesting that the peptide can be developed as a topical antibacterial agent for treating drug-resistant Staphylococcus aureus infections.
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Affiliation(s)
- Qiu Ying Lau
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - Jianguo Li
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; Singapore Eye Research Institute, The Academia, 20 College Road, Singapore 168751, Singapore
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Sheetal Sinha
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Yan Li
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - Fui Mee Ng
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - CongBao Kang
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - Surajit Bhattacharjya
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Chandra Verma
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore
| | - Cheng San Brian Chia
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore.
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Enhanced delivery of fixed-dose combination of synergistic antichagasic agents posaconazole-benznidazole based on amorphous solid dispersions. Eur J Pharm Sci 2018; 119:208-218. [PMID: 29679707 DOI: 10.1016/j.ejps.2018.04.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/26/2018] [Accepted: 04/17/2018] [Indexed: 10/17/2022]
Abstract
Posaconazole (PCZ) and benznidazole (BNZ) are known to show synergetic effect in treating the acute and chronic phases of Chagas disease, a neglected parasitic disease. However, as both compounds are poorly water soluble, the development of amorphous solid dispersions (ASDs) of a PCZ/BNZ fixed-dose combination in a water-soluble polymer becomes an attractive option to increase their apparent solubility and dissolution rate, potentially improving their oral bioavailability. The initial approach was to explore solvent evaporated solid dispertion (SD) systems for a PCZ/BNZ 50:50 (wt%) combination at several total drug loading levels (from SD with 10% to 50% drug loading) in water-soluble carriers, including polyvinylpyrrolidone (PVP K-30) and vinylpyrrolidone-vinyl acetate copolymer (PVPVA 64). Based on comparison of non-sink in vitro dissolution performance, ASD systems based on PVPVA was identified as the most effective carrier for a 50:50 (w/w %) fixed-dose combination of PCZ/BNZ to increase their apparent solubility and dissolution rate, mainly at 10% drug loading, which shows more expressive values of area under the curve (AUC) (7336.04 ± 3.77 min.μL/mL for PCZ and 15,795.02 ± 7.29 min.μL/mL for BNZ). Further characterization with polarized microscopy, powder X-ray diffraction, and thermal analysis reveals that there exists a threshold drug loading level at about 30% PCZ/BNZ, below which ASDs are obtained and above which a certain degree of crystallinity tends to result. Moreover, infrared spectroscopic analysis reveals the lack of hydrogen bonding interactions between the drugs (PCZ and BNZ) and the polymer (PVPVA) in the ASD, this is also confirmed through molecular dynamics simulations. The molecular modeling results further show that even in the absence of meaningful hydrogen bonding interactions, there is a greater tendency for PVPVA to interact preferentially with PCZ and BNZ through electrostatic interactions thereby contributing to the stability of the system. Thus, the present SD system has the advantage of presenting a fixed-dese combination of two synergistic antichagasic agents PCZ and BNZ together in amorphous form stabilized in the PVPVA matrix with enhanced dissolution, potentially improving their bioavailability and therapeutic activity in treating Chagas disease.
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130
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Zhang C, Lu C, Jing Z, Wu C, Piquemal JP, Ponder JW, Ren P. AMOEBA Polarizable Atomic Multipole Force Field for Nucleic Acids. J Chem Theory Comput 2018; 14:2084-2108. [PMID: 29438622 PMCID: PMC5893433 DOI: 10.1021/acs.jctc.7b01169] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The AMOEBA polarizable atomic multipole force field for nucleic acids is presented. Valence and electrostatic parameters were determined from high-level quantum mechanical data, including structures, conformational energy, and electrostatic potentials, of nucleotide model compounds. Previously derived parameters for the phosphate group and nucleobases were incorporated. A total of over 35 μs of condensed-phase molecular dynamics simulations of DNA and RNA molecules in aqueous solution and crystal lattice were performed to validate and refine the force field. The solution and/or crystal structures of DNA B-form duplexes, RNA duplexes, and hairpins were captured with an average root-mean-squared deviation from NMR structures below or around 2.0 Å. Structural details, such as base pairing and stacking, sugar puckering, backbone and χ-torsion angles, groove geometries, and crystal packing interfaces, agreed well with NMR and/or X-ray. The interconversion between A- and B-form DNAs was observed in ethanol-water mixtures at 328 K. Crystal lattices of B- and Z-form DNA and A-form RNA were examined with simulations. For the RNA tetraloop, single strand tetramers, and HIV TAR with 29 residues, the simulated conformational states, 3 J-coupling, nuclear Overhauser effect, and residual dipolar coupling data were compared with NMR results. Starting from a totally unstacked/unfolding state, the rCAAU tetranucleotide was folded into A-form-like structures during ∼1 μs molecular dynamics simulations.
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Affiliation(s)
- Changsheng Zhang
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Chao Lu
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States
| | - Zhifeng Jing
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Chuanjie Wu
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States
| | - Jean-Philip Piquemal
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
- Laboratoire de Chimie Théorique, Sorbonne Universités, UPMC, UMR7616 CNRS, Paris, France
| | - Jay W. Ponder
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States
| | - Pengyu Ren
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
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131
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Panczyk K, Gaweda K, Drach M, Plazinski W. Extension of the GROMOS 56a6 CARBO/CARBO_R Force Field for Charged, Protonated, and Esterified Uronates. J Phys Chem B 2018; 122:3696-3710. [PMID: 29558620 DOI: 10.1021/acs.jpcb.7b11548] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
An extension of the GROMOS 56a6CARBO/CARBO_R force field for hexopyranose-based carbohydrates is presented. The additional parameters describe the conformational properties of uronate residues. The three distinct chemical states of the carboxyl group are considered: deprotonated (negatively charged), protonated (neutral), and esterified (neutral). The parametrization procedure was based on quantum-chemical calculations, and the resulting parameters were tested in the context of (i) flexibility of the pyranose rings under different pH conditions, (ii) conformation of the glycosidic linkage of the (1 → 4)-type for uronates with different chemical states of carboxyl moieties, (iii) conformation of the exocyclic (i.e., carboxylate and lactol) moieties, and (iv) structure of the Ca2+-linked chain-chain complexes of uronates. The presently proposed parameters in combination with the 56a6CARBO/CARBO_R set can be used to describe the naturally occurring polyuronates, composed either of homogeneous (e.g., glucuronans) or heterogeneous (e.g., pectins, alginates) segments. The results of simulations relying on the new set of parameters indicate that the conformation of glycosidic linkage is nearly unaffected by the chemical state of the carboxyl group, in contrary to the ring conformational equilibria. The calculations for the poly(α-d-galacturonate)-Ca2+ and poly(α-l-guluronate)-Ca2+ complexes show that both parallel and anitiparallel arrangements of uronate chains are possible but differ in several structural aspects.
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Affiliation(s)
- Karina Panczyk
- Jerzy Haber Institute of Catalysis and Surface Chemistry , Polish Academy of Sciences , ul. Niezapominajek 8 , 30-239 Cracow , Poland
| | - Karolina Gaweda
- Jerzy Haber Institute of Catalysis and Surface Chemistry , Polish Academy of Sciences , ul. Niezapominajek 8 , 30-239 Cracow , Poland
| | - Mateusz Drach
- Department of Theoretical Chemistry, Faculty of Chemistry , M. Curie-Sklodowska University , pl. M. Curie-Sklodowskiej 3 , 20-031 Lublin , Poland
| | - Wojciech Plazinski
- Jerzy Haber Institute of Catalysis and Surface Chemistry , Polish Academy of Sciences , ul. Niezapominajek 8 , 30-239 Cracow , Poland
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132
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Kalms J, Schmidt A, Frielingsdorf S, Utesch T, Gotthard G, von Stetten D, van der Linden P, Royant A, Mroginski MA, Carpentier P, Lenz O, Scheerer P. Tracking the route of molecular oxygen in O 2-tolerant membrane-bound [NiFe] hydrogenase. Proc Natl Acad Sci U S A 2018; 115:E2229-E2237. [PMID: 29463722 PMCID: PMC5877991 DOI: 10.1073/pnas.1712267115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
[NiFe] hydrogenases catalyze the reversible splitting of H2 into protons and electrons at a deeply buried active site. The catalytic center can be accessed by gas molecules through a hydrophobic tunnel network. While most [NiFe] hydrogenases are inactivated by O2, a small subgroup, including the membrane-bound [NiFe] hydrogenase (MBH) of Ralstonia eutropha, is able to overcome aerobic inactivation by catalytic reduction of O2 to water. This O2 tolerance relies on a special [4Fe3S] cluster that is capable of releasing two electrons upon O2 attack. Here, the O2 accessibility of the MBH gas tunnel network has been probed experimentally using a "soak-and-freeze" derivatization method, accompanied by protein X-ray crystallography and computational studies. This combined approach revealed several sites of O2 molecules within a hydrophobic tunnel network leading, via two tunnel entrances, to the catalytic center of MBH. The corresponding site occupancies were related to the O2 concentrations used for MBH crystal derivatization. The examination of the O2-derivatized data furthermore uncovered two unexpected structural alterations at the [4Fe3S] cluster, which might be related to the O2 tolerance of the enzyme.
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Affiliation(s)
- Jacqueline Kalms
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, D-10117 Berlin, Germany
| | - Andrea Schmidt
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, D-10117 Berlin, Germany
| | | | - Tillmann Utesch
- Institut für Chemie, Technische Universität Berlin, D-10623 Berlin, Germany
| | | | | | - Peter van der Linden
- European Synchrotron Radiation Facility, F-38043 Grenoble, France
- Partnership for Soft Condensed Matter (PSCM), F-38043 Grenoble, France
| | - Antoine Royant
- European Synchrotron Radiation Facility, F-38043 Grenoble, France
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38000 Grenoble, France
| | | | - Philippe Carpentier
- European Synchrotron Radiation Facility, F-38043 Grenoble, France
- Univ. Grenoble Alpes, CNRS, CEA, Institut de Biosciences et Biotechnologies de Grenoble (BIG)-Laboratoire Chimie et Biologie des Métaux (LCBM), F-38000 Grenoble, France
| | - Oliver Lenz
- Institut für Chemie, Technische Universität Berlin, D-10623 Berlin, Germany
| | - Patrick Scheerer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, D-10117 Berlin, Germany;
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133
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Lin FY, Esposito EX, Tseng YJ. LeadOp+R: Structure-Based Lead Optimization With Synthetic Accessibility. Front Pharmacol 2018; 9:96. [PMID: 29556192 PMCID: PMC5845126 DOI: 10.3389/fphar.2018.00096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/29/2018] [Indexed: 11/13/2022] Open
Abstract
We previously described a structure-based fragment hopping for lead optimization using a pre-docked fragment database, “LeadOp,” that conceptually replaced “bad” fragments of a ligand with “good” fragments while leaving the core of the ligand intact thus improving the compound's activity. LeadOp was proven to optimize the query molecules and systematically developed improved analogs for each of our example systems. However, even with the fragment-based design from common building blocks, it is still a challenge for synthesis. In this work, “LeadOp+R” was developed based on 198 classical chemical reactions to consider the synthetic accessibility while optimizing leads. LeadOp+R first allows user to identify a preserved space defined by the volume occupied by a fragment of the query molecule to be preserved. Then LeadOp+R searches for building blocks with the same preserved space as initial reactants and grows molecules toward the preferred receptor-ligand interactions according to reaction rules from reaction database in LeadOp+R. Multiple conformers of each intermediate product were considered and evaluated at each step. The conformer with the best group efficiency score would be selected as the initial conformer of the next building block until the program finished optimization for all selected receptor-ligand interactions. The LeadOp+R method was tested with two biomolecular systems: Tie-2 kinase and human 5-lipoxygenase. The LeadOp+R methodology was able to optimize the query molecules and systematically developed improved analogs for each of our example systems. The suggested synthetic routes for compounds proposed by LeadOp+R were the same as the published synthetic routes devised by the synthetic/organic chemists.
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Affiliation(s)
- Fang-Yu Lin
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan
| | | | - Yufeng J Tseng
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.,Department of Computer Science and Information Engineering, National Taiwan University, Taipei, Taiwan
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134
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Ni T, Williams SI, Rezelj S, Anderluh G, Harlos K, Stansfeld PJ, Gilbert RJC. Structures of monomeric and oligomeric forms of the Toxoplasma gondii perforin-like protein 1. SCIENCE ADVANCES 2018; 4:eaaq0762. [PMID: 29750191 PMCID: PMC5943054 DOI: 10.1126/sciadv.aaq0762] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 02/09/2018] [Indexed: 05/30/2023]
Abstract
Toxoplasma and Plasmodium are the parasitic agents of toxoplasmosis and malaria, respectively, and use perforin-like proteins (PLPs) to invade host organisms and complete their life cycles. The Toxoplasma gondii PLP1 (TgPLP1) is required for efficient exit from parasitophorous vacuoles in which proliferation occurs. We report structures of the membrane attack complex/perforin (MACPF) and Apicomplexan PLP C-terminal β-pleated sheet (APCβ) domains of TgPLP1. The MACPF domain forms hexameric assemblies, with ring and helix geometries, and the APCβ domain has a novel β-prism fold joined to the MACPF domain by a short linker. Molecular dynamics simulations suggest that the helical MACPF oligomer preserves a biologically important interface, whereas the APCβ domain binds preferentially through a hydrophobic loop to membrane phosphatidylethanolamine, enhanced by the additional presence of inositol phosphate lipids. This mode of membrane binding is supported by site-directed mutagenesis data from a liposome-based assay. Together, these structural and biophysical findings provide insights into the molecular mechanism of membrane targeting by TgPLP1.
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Affiliation(s)
- Tao Ni
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Sophie I. Williams
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Saša Rezelj
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Karl Harlos
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Phillip J. Stansfeld
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Robert J. C. Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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135
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Willems N, Lelimousin M, Skjold-Jørgensen J, Svendsen A, Sansom MS. The effect of mutations in the lid region of Thermomyces lanuginosus lipase on interactions with triglyceride surfaces: A multi-scale simulation study. Chem Phys Lipids 2018; 211:4-15. [DOI: 10.1016/j.chemphyslip.2017.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/25/2017] [Accepted: 08/08/2017] [Indexed: 10/19/2022]
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136
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Yan H, Han Z, Li K, Li G, Wei X. Molecular Dynamics Simulation of the pH-Induced Structural Transitions in CTAB/NaSal Solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:351-358. [PMID: 29215892 DOI: 10.1021/acs.langmuir.7b03715] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We performed molecular dynamics simulations to study the pH-induced structural transitions for aqueous mixtures of a cationic surfactant (cetyltrimethylammonium bromide, CTAB) and a hydrotrope (sodium salicylate, NaSal). We obtained rigid cylindrical, spherical, and flexible cylindrical micelles at pH 7, 2, and 0, respectively, which agrees well with the experimental results of Umeasiegbu et al. (Langmuir 2016, 32, 655). By analyzing the different micellar structural properties, including distribution and molecular orientation of CTA+ and Sal- inside the micelle, we found that the binding form of the protonated salicylate molecules with CTA+ is different from that of Sal- ions. Because of the protonation of salicylate molecules with reduction in pH, their hydrogen bonding interactions with water molecules strengthened and the electrostatic interactions with CTA+ headgroups weakened. Thus, the repulsion of the CTA+ headgroups led to the breakage of the cylindrical micelle into spherical ones. At pH 0, the H-bond-strengthened cation-π interactions between salicylate and CTA+ were verified. We concluded that the penetration of salicylate molecules inside the micelle and the strong association of Cl- ions on the micellar surface play a key role in the formation of a flexible cylindrical micelle. This work provides an atomic-level insight into the mechanism of pH-induced shape transitions in the CTAB/NaSal systems, which is expected to be helpful to understand the aggregate behavior of cationic surfactant-hydrotrope solution.
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Affiliation(s)
| | - Zhe Han
- Environmental Engineering Materials, Advanced Materials Institute, Shandong Academy of Sciences , Jinan 250014, China
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137
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Suhaj A, Le Marois A, Williamson DJ, Suhling K, Lorenz CD, Owen DM. PRODAN differentially influences its local environment. Phys Chem Chem Phys 2018; 20:16060-16066. [DOI: 10.1039/c8cp00543e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PRODAN influences its local environment at the nanoscale differently between ordered and disordered phases as shown by MD simulations.
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Affiliation(s)
- Adam Suhaj
- Department of Physics and Randall Division of Cell and Molecular Biophysics
- King's College London
- London
- UK
| | | | - David J. Williamson
- Randall Division of Cell and Molecular Biophysics
- King's College London
- London
- UK
| | | | | | - Dylan M. Owen
- Department of Physics and Randall Division of Cell and Molecular Biophysics
- King's College London
- London
- UK
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138
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Musso L, Mazzini S, Rossini A, Castagnoli L, Scaglioni L, Artali R, Di Nicola M, Zunino F, Dallavalle S. c-MYC G-quadruplex binding by the RNA polymerase I inhibitor BMH-21 and analogues revealed by a combined NMR and biochemical Approach. Biochim Biophys Acta Gen Subj 2017; 1862:615-629. [PMID: 29229300 DOI: 10.1016/j.bbagen.2017.12.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 11/03/2017] [Accepted: 12/07/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND Pyridoquinazolinecarboxamides have been reported as RNA polymerase I inhibitors and represent a novel class of potential antitumor agents. BMH-21, was reported to intercalate with GC-rich rDNA, resulting in nucleolar stress as a primary mechanism of cytotoxicity. METHODS The interaction of BMH-21 and analogues with DNA G-quadruplex structures was studied by NMR and molecular modelling. The cellular response was investigated in a panel of human tumor cell lines and protein expression was examined by Western Blot analysis. RESULTS AND CONCLUSIONS We explored the ability of BMH-21 and its analogue 2 to bind to G-quadruplex present in the c-MYC promoter, by NMR and molecular modelling studies. We provide evidence that both compounds are not typical DNA intercalators but are effective binders of the tested G-quadruplex. The interaction with c-MYC G-quadruplex was reflected in down-regulation of c-Myc expression in human tumor cells. The inhibitory effect was almost complete in lymphoma cells SUDHL4 characterized by overexpression of c-Myc protein. This downregulation reflected an early and persistent modulation of cMyc mRNA. Given the relevance of c-MYC in regulation of ribosome biogenesis, it is conceivable that the inhibition of c-MYC contributes to the perturbation of nuclear functions and RNA polymerase I activity. Similar experiments with CX-5461, another RNA polymerase I transcription inhibitor, indicate the same behaviour in G-quadruplex stabilization. GENERAL SIGNIFICANCE Our results support the hypothesis that BMH-21 and analogue compounds share the same mechanism, i.e. G-quadruplex binding as a primary event of a cascade leading to inhibition of RNA polymerase I and apoptosis.
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MESH Headings
- Antineoplastic Agents/pharmacology
- Benzothiazoles/pharmacology
- Blotting, Western
- Cell Line, Tumor
- DNA, Neoplasm/drug effects
- DNA, Neoplasm/genetics
- Enzyme Inhibitors/pharmacology
- G-Quadruplexes/drug effects
- Gene Expression Regulation, Neoplastic/drug effects
- Genes, myc/drug effects
- Heterocyclic Compounds, 4 or More Rings/pharmacology
- Humans
- Models, Molecular
- Molecular Docking Simulation
- Molecular Structure
- Naphthyridines/pharmacology
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Nuclear Magnetic Resonance, Biomolecular
- Organelle Biogenesis
- Promoter Regions, Genetic/drug effects
- RNA Polymerase I/antagonists & inhibitors
- Ribosomes/metabolism
- Transcription, Genetic/drug effects
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Affiliation(s)
- Loana Musso
- Department of Food, Environmental and Nutritional Sciences, Division of Chemistry and Molecular Biology, Università degli Studi di Milano, via Celoria 2, I-20133 Milano, Italy
| | - Stefania Mazzini
- Department of Food, Environmental and Nutritional Sciences, Division of Chemistry and Molecular Biology, Università degli Studi di Milano, via Celoria 2, I-20133 Milano, Italy.
| | - Anna Rossini
- Fondazione IRCCS, Istituto Nazionale dei Tumori, via Venezian 1, 20133 Milano, Italy
| | - Lorenzo Castagnoli
- Molecular Targeting Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale Tumori, via Venezian 1, 20133 Milano, Italy
| | - Leonardo Scaglioni
- Department of Food, Environmental and Nutritional Sciences, Division of Chemistry and Molecular Biology, Università degli Studi di Milano, via Celoria 2, I-20133 Milano, Italy
| | - Roberto Artali
- Scientia Advice, di Roberto Artali, 20832 Desio, MB, Italy
| | - Massimo Di Nicola
- Fondazione IRCCS, Istituto Nazionale dei Tumori, via Venezian 1, 20133 Milano, Italy
| | - Franco Zunino
- Fondazione IRCCS, Istituto Nazionale dei Tumori, via Venezian 1, 20133 Milano, Italy
| | - Sabrina Dallavalle
- Department of Food, Environmental and Nutritional Sciences, Division of Chemistry and Molecular Biology, Università degli Studi di Milano, via Celoria 2, I-20133 Milano, Italy
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Li LJ, Wu ZY, Yu Y, Zhang LJ, Zhu YB, Ni H, Chen F. Development and characterization of an α-l-rhamnosidase mutant with improved thermostability and a higher efficiency for debittering orange juice. Food Chem 2017; 245:1070-1078. [PMID: 29287324 DOI: 10.1016/j.foodchem.2017.11.064] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 11/11/2017] [Accepted: 11/16/2017] [Indexed: 10/18/2022]
Abstract
The glycoside hydrolase, α-l-rhamnosidase, could remove the bitter taste of naringin from citrus juices. However, most α-l-rhamnosidases are easily deactivated at high temperatures, limiting the practice in debittering citrus juices. The V529A mutant of the α-l-rhamnosidase r-Rha1 from Aspergillus niger JMU-TS528 was developed with improved thermostability using directed evolution technology and site-directed mutagenesis. The enzyme mutant had a half-live of thermal inactivation T(1/2) of 1.92 h, 25.00 min, and 2 min at 60, 65, and 70 °C, respectively. In addition, it had improved substrate affinity and better resistance to the inhibition of glucose. The improved substrate affinity was related to its lowered binding energy. Most significantly, the naringin content was reduced to below the bitter taste threshold by treatment with 75 U/mL of the mutant during the preheating process of orange juice production. The comprehensive results indicate that thermostability improvement could promote the practical value of α-l-rhamnosidase in citrus juice processing.
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Affiliation(s)
- Li Jun Li
- College of Food and Biology Engineering, Jimei University, Xiamen, Fujian Province 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, Fujian Province 361021, China; Research Center of Food Biotechnology of Xiamen City, Xiamen, Fujian Province 361021, China
| | - Zhe Yu Wu
- College of Food and Biology Engineering, Jimei University, Xiamen, Fujian Province 361021, China
| | - Yue Yu
- College of Food and Biology Engineering, Jimei University, Xiamen, Fujian Province 361021, China
| | - Lu Jia Zhang
- College of Chemistry and Molecular Engineering, East China Normal University, Shanghai 201100, China
| | - Yan Bing Zhu
- College of Food and Biology Engineering, Jimei University, Xiamen, Fujian Province 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, Fujian Province 361021, China; Research Center of Food Biotechnology of Xiamen City, Xiamen, Fujian Province 361021, China
| | - Hui Ni
- College of Food and Biology Engineering, Jimei University, Xiamen, Fujian Province 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, Fujian Province 361021, China; Research Center of Food Biotechnology of Xiamen City, Xiamen, Fujian Province 361021, China.
| | - Feng Chen
- College of Food and Biology Engineering, Jimei University, Xiamen, Fujian Province 361021, China; Department of Food, Nutrition and Packaging Sciences, Clemson University, Clemson, SC 29634, USA
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140
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Garcia-Jimenez A, Teruel-Puche JA, Garcia-Ruiz PA, Saura-Sanmartin A, Berna J, Garcia-Canovas F, Rodriguez-Lopez JN. Structural and kinetic considerations on the catalysis of deoxyarbutin by tyrosinase. PLoS One 2017; 12:e0187845. [PMID: 29136639 PMCID: PMC5685642 DOI: 10.1371/journal.pone.0187845] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 10/26/2017] [Indexed: 11/18/2022] Open
Abstract
Deoxyarbutin, a potent inhibitor of tyrosinase, could act as substrate of the enzyme. Oxytyrosinase is able to hydroxylate deoxyarbutin and finishes the catalytic cycle by oxidizing the formed o-diphenol to quinone, while the enzyme becomes deoxytyrosinase, which evolves to oxytyrosinase in the presence of oxygen. This compound is the only one described that does not release o-diphenol after the hydroxylation step. Oxytyrosinase hydroxylates the deoxyarbutin in ortho position of the phenolic hydroxyl group by means of an aromatic electrophilic substitution. As the oxygen orbitals and the copper atoms are not coplanar, but in axial/equatorial position, the concerted oxidation/reduction cannot occur and the release of a copper atom to bind again in coplanar position, enabling the oxidation/reduction or release of the o-diphenol from the active site to the medium. In the case of deoxyarbutin, the o-diphenol formed is repulsed by the water due to its hydrophobicity, and so can bind correctly and be oxidized to a quinone before being released. Deoxyarbutin has been characterized with: [Formula: see text] = 1.95 ± 0.06 s-1 and [Formula: see text] = 33 ± 4 μM. Computational simulations of the interaction of β-arbutin, deoxyarbutin and their o-diphenol products with tyrosinase show how these ligands bind at the copper centre of tyrosinase. The presence of an energy barrier in the release of the o-diphenol product of deoxyarbutin, which is not present in the case of β-arbutin, together with the differences in polarity and, consequently differences in their interaction with water help understand the differences in the kinetic behaviour of both compounds. Therefore, it is proposed that the release of the o-diphenol product of deoxyarbutin from the active site might be slower than in the case of β-arbutin, contributing to its oxidation to a quinone before being released from the protein into the water phase.
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Affiliation(s)
- Antonio Garcia-Jimenez
- GENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Espinardo, Murcia, Spain
| | - Jose Antonio Teruel-Puche
- Group of Molecular Interactions in Membranes, Department of Biochemistry and Molecular Biology-A, University of Murcia, Espinardo, Murcia, Spain
| | - Pedro Antonio Garcia-Ruiz
- Group of Chemistry of Carbohydrates, Industrial Polymers and Additives, Department of Organic Chemistry, Faculty of Veterinary, University of Murcia, Espinardo, Murcia, Spain
| | - Adrian Saura-Sanmartin
- Group of Synthetic Organic Chemistry, Department of Organic Chemistry, Faculty of Chemistry, University of Murcia, Espinardo, Murcia, Spain
| | - Jose Berna
- Group of Synthetic Organic Chemistry, Department of Organic Chemistry, Faculty of Chemistry, University of Murcia, Espinardo, Murcia, Spain
| | - Francisco Garcia-Canovas
- GENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Espinardo, Murcia, Spain
- * E-mail:
| | - José Neptuno Rodriguez-Lopez
- GENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Espinardo, Murcia, Spain
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141
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Nazarychev VM, Larin SV, Lyulin AV, Dingemans T, Kenny JM, Lyulin SV. Atomistic Molecular Dynamics Simulations of the Initial Crystallization Stage in an SWCNT-Polyetherimide Nanocomposite. Polymers (Basel) 2017; 9:polym9100548. [PMID: 30965851 PMCID: PMC6418835 DOI: 10.3390/polym9100548] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 10/13/2017] [Accepted: 10/19/2017] [Indexed: 01/23/2023] Open
Abstract
Crystallization of all-aromatic heterocyclic polymers typically results in an improvement of their thermo-mechanical properties. Nucleation agents may be used to promote crystallization, and it is well known that the incorporation of nanoparticles, and in particular carbon-based nanofillers, may induce or accelerate crystallization through nucleation. The present study addresses the structural properties of polyetherimide-based nanocomposites and the initial stages of polyetherimide crystallization as a result of single-walled carbon nanotube (SWCNT) incorporation. We selected two amorphous thermoplastic polyetherimides ODPA-P3 and aBPDA-P3 based on 3,3′,4,4′-oxydiphthalic dianhydride (ODPA), 2,3′,3,4′-biphenyltetracarboxylic dianhydride (aBPDA) and diamine 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene (P3) and simulated the onset of crystallization in the presence of SWCNTs using atomistic molecular dynamics. For ODPA-P3, we found that the planar phthalimide and phenylene moieties show pronounced ordering near the CNT (carbon nanotube) surface, which can be regarded as the initial stage of crystallization. We will discuss two possible mechanisms for ODPA-P3 crystallization in the presence of SWCNTs: the spatial confinement caused by the CNTs and π–π interactions at the CNT-polymer matrix interface. Based on our simulation results, we propose that ODPA-P3 crystallization is most likely initiated by favorable π–π interactions between the carbon nanofiller surface and the planar ODPA-P3 phthalimide and phenylene moieties.
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Affiliation(s)
- Victor M Nazarychev
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bol'shoi pr. 31 (V.O.), St. Petersburg 199004, Russia.
| | - Sergey V Larin
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bol'shoi pr. 31 (V.O.), St. Petersburg 199004, Russia.
| | - Alexey V Lyulin
- Theory of Polymers and Soft Matter Group, Technische Universiteit Eindhoven, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
| | - Theo Dingemans
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Murray Hall 1113, 121 South Road, Chapel Hill, NC 27599-3050, USA.
| | - Jose M Kenny
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bol'shoi pr. 31 (V.O.), St. Petersburg 199004, Russia.
- Materials Science and Technology Centre, University of Perugia, Loc. Pentima, 4, 05100 Terni, Italy.
| | - Sergey V Lyulin
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bol'shoi pr. 31 (V.O.), St. Petersburg 199004, Russia.
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142
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da Costa CT, Pedebos C, Verli H, Fett-Neto AG. The role of Zn2+, dimerization and N-glycosylation in the interaction of Auxin-Binding Protein 1 (ABP1) with different auxins. Glycobiology 2017; 27:1109-1119. [DOI: 10.1093/glycob/cwx080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 09/04/2017] [Indexed: 01/12/2023] Open
Affiliation(s)
- Cibele Tesser da Costa
- Center for Biotechnology, Federal University of Rio Grande do Sul (UFRGS), CP 15005, Porto Alegre, RS 91501-970, Brazil
| | - Conrado Pedebos
- Center for Biotechnology, Federal University of Rio Grande do Sul (UFRGS), CP 15005, Porto Alegre, RS 91501-970, Brazil
| | - Hugo Verli
- Center for Biotechnology, Federal University of Rio Grande do Sul (UFRGS), CP 15005, Porto Alegre, RS 91501-970, Brazil
| | - Arthur Germano Fett-Neto
- Center for Biotechnology, Federal University of Rio Grande do Sul (UFRGS), CP 15005, Porto Alegre, RS 91501-970, Brazil
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143
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Li J, Han Y, Qu G, Cheng J, Xue C, Gao X, Sun T, Ding W. Molecular dynamics simulation of the aggregation behavior of N-Dodecyl-N,N-Dimethyl-3-Ammonio-1-Propanesulfonate/sodium dodecyl benzene sulfonate surfactant mixed system at oil/water interface. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.07.088] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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144
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Yahyaei M, Mehrnejad F, Naderi-manesh H, Rezayan AH. Follicle-stimulating hormone encapsulation in the cholesterol-modified chitosan nanoparticles via molecular dynamics simulations and binding free energy calculations. Eur J Pharm Sci 2017; 107:126-137. [DOI: 10.1016/j.ejps.2017.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 06/02/2017] [Accepted: 07/07/2017] [Indexed: 12/17/2022]
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145
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Zhu W, Khalifa I, Peng J, Li C. Position and orientation of gallated proanthocyanidins in lipid bilayer membranes: influence of polymerization degree and linkage type. J Biomol Struct Dyn 2017; 36:2862-2875. [DOI: 10.1080/07391102.2017.1369163] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Wei Zhu
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Ibrahim Khalifa
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jinming Peng
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Chunmei Li
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Environment Correlative Food Science, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China
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146
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Santos DES, Pol-Fachin L, Lins RD, Soares TA. Polymyxin Binding to the Bacterial Outer Membrane Reveals Cation Displacement and Increasing Membrane Curvature in Susceptible but Not in Resistant Lipopolysaccharide Chemotypes. J Chem Inf Model 2017; 57:2181-2193. [DOI: 10.1021/acs.jcim.7b00271] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Denys E. S. Santos
- Department
of Fundamental Chemistry, Federal University of Pernambuco, 50740-560 Recife, Brazil
| | - Laércio Pol-Fachin
- Department
of Fundamental Chemistry, Federal University of Pernambuco, 50740-560 Recife, Brazil
- Aggeu Magalhães Institute, Oswaldo Cruz Foundation, 50740-465 Recife, Brazil
| | - Roberto D. Lins
- Aggeu Magalhães Institute, Oswaldo Cruz Foundation, 50740-465 Recife, Brazil
| | - Thereza A. Soares
- Department
of Fundamental Chemistry, Federal University of Pernambuco, 50740-560 Recife, Brazil
- Department
of Chemistry, Umeå Center for Microbial Research, Umeå University, 90.187 Umeå, Sweden
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147
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Pappalardo M, Collu F, Macpherson J, Michaelis M, Fraternali F, Wass MN. Investigating Ebola virus pathogenicity using molecular dynamics. BMC Genomics 2017; 18:566. [PMID: 28812539 PMCID: PMC5558184 DOI: 10.1186/s12864-017-3912-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Ebolaviruses have been known to cause deadly disease in humans for 40 years and have recently been demonstrated in West Africa to be able to cause large outbreaks. Four Ebolavirus species cause severe disease associated with high mortality in humans. Reston viruses are the only Ebolaviruses that do not cause disease in humans. Conserved amino acid changes in the Reston virus protein VP24 compared to VP24 of other Ebolaviruses have been suggested to alter VP24 binding to host cell karyopherins resulting in impaired inhibition of interferon signalling, which may explain the difference in human pathogenicity. Here we used protein structural analysis and molecular dynamics to further elucidate the interaction between VP24 and KPNA5. RESULTS As a control experiment, we compared the interaction of wild-type and R137A-mutant (known to affect KPNA5 binding) Ebola virus VP24 with KPNA5. Results confirmed that the R137A mutation weakens direct VP24-KPNA5 binding and enables water molecules to penetrate at the interface. Similarly, Reston virus VP24 displayed a weaker interaction with KPNA5 than Ebola virus VP24, which is likely to reduce the ability of Reston virus VP24 to prevent host cell interferon signalling. CONCLUSION Our results provide novel molecular detail on the interaction of Reston virus VP24 and Ebola virus VP24 with human KPNA5. The results indicate a weaker interaction of Reston virus VP24 with KPNA5 than Ebola virus VP24, which is probably associated with a decreased ability to interfere with the host cell interferon response. Hence, our study provides further evidence that VP24 is a key player in determining Ebolavirus pathogenicity.
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Affiliation(s)
| | - Francesca Collu
- Randall Division of Cell and Molecular Biophysics King's College London, London, UK
| | - James Macpherson
- Randall Division of Cell and Molecular Biophysics King's College London, London, UK
| | | | - Franca Fraternali
- Randall Division of Cell and Molecular Biophysics King's College London, London, UK.
| | - Mark N Wass
- School of Biosciences, University of Kent, Kent, UK.
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148
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Farrotti A, Conflitti P, Srivastava S, Ghosh JK, Palleschi A, Stella L, Bocchinfuso G. Molecular Dynamics Simulations of the Host Defense Peptide Temporin L and Its Q3K Derivative: An Atomic Level View from Aggregation in Water to Bilayer Perturbation. Molecules 2017; 22:molecules22071235. [PMID: 28737669 PMCID: PMC6152314 DOI: 10.3390/molecules22071235] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/20/2017] [Accepted: 07/20/2017] [Indexed: 12/03/2022] Open
Abstract
Temporin L (TempL) is a 13 residue Host Defense Peptide (HDP) isolated from the skin of frogs. It has a strong affinity for lipopolysaccharides (LPS), which is related to its high activity against Gram-negative bacteria and also to its strong tendency to neutralize the pro-inflammatory response caused by LPS release from inactivated bacteria. A designed analog with the Q3K substitution shows an enhancement in both these activities. In the present paper, Molecular Dynamics (MD) simulations have been used to investigate the origin of these improved properties. To this end, we have studied the behavior of the peptides both in water solution and in the presence of LPS lipid-A bilayers, demonstrating that the main effect through which the Q3K substitution improves the peptide activities is the destabilization of peptide aggregates in water.
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Affiliation(s)
- Andrea Farrotti
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma "Tor Vergata", Rome 00133, Italy.
| | - Paolo Conflitti
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma "Tor Vergata", Rome 00133, Italy.
| | - Saurabh Srivastava
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India.
| | - Jimut Kanti Ghosh
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India.
| | - Antonio Palleschi
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma "Tor Vergata", Rome 00133, Italy.
| | - Lorenzo Stella
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma "Tor Vergata", Rome 00133, Italy.
| | - Gianfranco Bocchinfuso
- Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma "Tor Vergata", Rome 00133, Italy.
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149
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Mohan S, Hemachandran H, Sneha P, George Priya Doss C, Godwin Christopher J, Jayaraman G, Ramamoorthy S. Structural insights into the binding mode and conformational changes of BSA induced by bixin and crocin. J Biomol Struct Dyn 2017; 36:2085-2098. [DOI: 10.1080/07391102.2017.1342565] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Sankari Mohan
- School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India
| | - Hridya Hemachandran
- School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India
| | - P. Sneha
- School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India
| | - C. George Priya Doss
- School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India
| | - J. Godwin Christopher
- School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India
| | - Gurunathan Jayaraman
- School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India
| | - Siva Ramamoorthy
- School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India
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150
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Ortiz-Suarez ML, Samsudin F, Piggot TJ, Bond PJ, Khalid S. Full-Length OmpA: Structure, Function, and Membrane Interactions Predicted by Molecular Dynamics Simulations. Biophys J 2017; 111:1692-1702. [PMID: 27760356 PMCID: PMC5071624 DOI: 10.1016/j.bpj.2016.09.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/30/2016] [Accepted: 09/06/2016] [Indexed: 12/02/2022] Open
Abstract
OmpA is a multidomain protein found in the outer membranes of most Gram-negative bacteria. Despite a wealth of reported structural and biophysical studies, the structure-function relationships of this protein remain unclear. For example, it is still debated whether it functions as a pore, and the precise molecular role it plays in attachment to the peptidoglycan of the periplasm is unknown. The absence of a consensus view is partly due to the lack of a complete structure of the full-length protein. To address this issue, we performed molecular-dynamics simulations of the full-length model of the OmpA dimer proposed by Robinson and co-workers. The N-terminal domains were embedded in an asymmetric model of the outer membrane, with lipopolysaccharide molecules in the outer leaflet and phospholipids in the inner leaflet. Our results reveal a large dimerization interface within the membrane environment, ensuring that the dimer is stable over the course of the simulations. The linker is flexible, expanding and contracting to pull the globular C-terminal domain up toward the membrane or push it down toward the periplasm, suggesting a possible mechanism for providing mechanical stability to the cell. The external loops were more stabilized than was observed in previous studies due to the extensive dimerization interface and presence of lipopolysaccharide molecules in our outer-membrane model, which may have functional consequences in terms of OmpA adhesion to host cells. In addition, the pore-gating behavior of the protein was modulated compared with previous observations, suggesting a possible role for dimerization in channel regulation.
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Affiliation(s)
- Maite L Ortiz-Suarez
- School of Chemistry, Highfield Campus, University of Southampton, Southampton, United Kingdom
| | - Firdaus Samsudin
- School of Chemistry, Highfield Campus, University of Southampton, Southampton, United Kingdom
| | - Thomas J Piggot
- School of Chemistry, Highfield Campus, University of Southampton, Southampton, United Kingdom
| | - Peter J Bond
- Bioinformatics Institute (A(∗)STAR), Singapore, Singapore; Department of Biological Sciences, National University of Singapore, Singapore, Singapore.
| | - Syma Khalid
- School of Chemistry, Highfield Campus, University of Southampton, Southampton, United Kingdom.
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