Quercetin pentaacetate inhibits in vitro human respiratory syncytial virus adhesion.

Made available in DSpace on 2020-12-12T01:06:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Human respiratory syncytial virus (hRSV) is one of the main etiological agents of diseases of the lower respiratory tract and is often responsible for the hospitalization of children and the elderly. To date, treatments are only palliative and there is no vaccine available. Natural products show exceptional structural diversity and they have played a vital role in drug research. Several investigations focused on applied structural modification of natural products to improved metabolic stability, solubility and biological actions them. Quercetin is a flavonoid that presents several biological activities, including anti-hRSV role. Some works criticize the pharmacological use of Quercetin because it has low solubility and low specificity. In this sense, we acetylated Quercetin structure and we used in vitro and in silico assays to compare anti-hRSV function between Quercetin (Q0) and its derivative molecule (Q1). Q1 shows lower cytotoxic effect than Q0 on HEp-2 cells. In addition, Q1 was more efficient than Q0 to protect HEp-2 cells infected with different multiplicity of infection (0.1–1 MOI). The virucidal effects of Q0 and Q1 suggest interaction between these molecules and viral particle. Dynamic molecular results suggest that Q0 and Q1 may interact with F-protein on hRSV surface in an important region to adhesion and viral infection. Q1 interaction with F-protein showed ΔG= -14.22 kcal/mol and it was more stable than Q0. Additional, MTT and plate assays confirmed that virucidal Q1 effects occurs during adhesion step of cycle hRSV replication. In conclusion, acetylation improves anti-hRSV Quercetin effects because Quercetin pentaacetate could interact with F-protein with lower binding energy and better stability to block viral adhesion. These results show alternative anti-hRSV strategy and contribute to drug discovery and development. Universidade Estadual Paulista UNESP (FCLAssis) Universidade Estadual Paulista UNESP IBILCE Centro Multiusuário de Inovação Biomolecular (CMIB) Universidade Estadual Paulista UNESP IBILCE Department of Biology University of Rome Tor Vergata, Via della Ricerca Scientifica 1 Universidade Estadual Paulista UNESP (FCLAssis) Universidade Estadual Paulista UNESP IBILCE Centro Multiusuário de Inovação Biomolecular (CMIB) Universidade Estadual Paulista UNESP IBILCE FAPESP: 2014/12298-

Comprehensive Fragment Screening of the SARS-CoV-2 Proteome Explores Novel Chemical Space for Drug Development

12 pags., 4 figs., 3 tabs.SARS-CoV-2 (SCoV2) and its variants of concern pose serious challenges to the public health. The variants increased challenges to vaccines, thus necessitating for development of new intervention strategies including anti-virals. Within the international Covid19-NMR consortium, we have identified binders targeting the RNA genome of SCoV2. We established protocols for the production and NMR characterization of more than 80 % of all SCoV2 proteins. Here, we performed an NMR screening using a fragment library for binding to 25 SCoV2 proteins and identified hits also against previously unexplored SCoV2 proteins. Computational mapping was used to predict binding sites and identify functional moieties (chemotypes) of the ligands occupying these pockets. Striking consensus was observed between NMR-detected binding sites of the main protease and the computational procedure. Our investigation provides novel structural and chemical space for structure-based drug design against the SCoV2 proteome.Work at BMRZ is supported by the state of Hesse. Work in Covid19-NMR was supported by the Goethe Corona Funds, by the IWBEFRE-program 20007375 of state of Hesse, the DFG through CRC902: “Molecular Principles of RNA-based regulation.” and through infrastructure funds (project numbers: 277478796, 277479031, 392682309, 452632086, 70653611) and by European Union’s Horizon 2020 research and innovation program iNEXT-discovery under grant agreement No 871037. BY-COVID receives funding from the European Union’s Horizon Europe Research and Innovation Programme under grant agreement number 101046203. “INSPIRED” (MIS 5002550) project, implemented under the Action “Reinforcement of the Research and Innovation Infrastructure,” funded by the Operational Program “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014–2020) and co-financed by Greece and the EU (European Regional Development Fund) and the FP7 REGPOT CT-2011-285950—“SEE-DRUG” project (purchase of UPAT’s 700 MHz NMR equipment). The support of the CERM/CIRMMP center of Instruct-ERIC is gratefully acknowledged. This work has been funded in part by a grant of the Italian Ministry of University and Research (FISR2020IP_02112, ID-COVID) and by Fondazione CR Firenze. A.S. is supported by the Deutsche Forschungsgemeinschaft [SFB902/B16, SCHL2062/2-1] and the Johanna Quandt Young Academy at Goethe [2019/AS01]. M.H. and C.F. thank SFB902 and the Stiftung Polytechnische Gesellschaft for the Scholarship. L.L. work was supported by the French National Research Agency (ANR, NMR-SCoV2-ORF8), the Fondation de la Recherche Médicale (FRM, NMR-SCoV2-ORF8), FINOVI and the IR-RMN-THC Fr3050 CNRS. Work at UConn Health was supported by grants from the US National Institutes of Health (R01 GM135592 to B.H., P41 GM111135 and R01 GM123249 to J.C.H.) and the US National Science Foundation (DBI 2030601 to J.C.H.). Latvian Council of Science Grant No. VPP-COVID-2020/1-0014. National Science Foundation EAGER MCB-2031269. This work was supported by the grant Krebsliga KFS-4903-08-2019 and SNF-311030_192646 to J.O. P.G. (ITMP) The EOSC Future project is co-funded by the European Union Horizon Programme call INFRAEOSC-03-2020—Grant Agreement Number 101017536. Open Access funding enabled and organized by Projekt DEALPeer reviewe

Estudo de interação dos flavonóides Isovitexina e 2-Fenilcromona com a Albumina do Soro Humano: abordagem experimental e computacional

Os flavonóides fazem parte de uma ampla classe de compostos polifenólicos os quais ocorrem naturalmente nas plantas e podem ser encontrados nas sementes, caules, folhas, flores e/ou frutos. Estudos recentes indicam que esses compostos polifenólicos podem apresentar uma variedade significativa de atividades biológicas benéficas para a saúde humana, como por exemplo: antioxidante, anti-inflamatória, antibacteriana, antiviral e anticancerígena. A Albumina do Soro Humano (HSA) é a principal proteína extracelular presente no plasma sanguíneo. A função central dessa proteína é transportar e distribuir ligantes endógenos e exógenos para diferentes alvos moleculares no corpo humano. Por tais aspectos, torna-se importante o desenvolvimento de estudos que caracterizam a interação dos flavonóides com a proteína transportadora HSA. Este trabalho investiga a interação dos flavonóides Isovitexina (ISO) e 2-Fenilcromona (2PHE) com a HSA, utilizando técnicas experimentais de espectroscopia de fluorescência, absorbância UV-Vis, dicroísmo circular (CD) e infravermelho com transformada de Fourier (FT-IR); juntamente com ferramentas computacionais de cálculo {\it{ab initio}}, dinâmica molecular e modelagem molecular. A integração dessas abordagens experimentais e computacionais possibilita caracterizar a formação dos complexos HSA-flavonóides, determinando aspectos físico-químicos como: constantes de afinidade, parâmetros termodinâmicos, número de sítios de ligação, perfil de cooperatividade e resíduos de aminoácidos responsáveis pelas interações proteína-flavonóides (hidrofóbicas e eletrostáticas).Flavonoids belong to a large class of polyphenolic compounds which occur naturally in plants and can be found seeds, stems, leaves, flowers and/or fruits. Recent studies indicate that these polyphenolic compounds can present a significant variety of beneficial biological activities on human health, such as: antioxidant, anti-inflammatory, antibacterial, antiviral, and anticancer. Human Serum Ambumin (HSA) is the main extracellular protein presents in blood plasma. The core function of this protein is to carry and distribute endogenous and exogenous ligands to different molecular targets in the human body. For these aspects, it is important to develop studies that characterize the interaction of the flavonoids with the carrier protein HSA. This work investigates the interaction of the flavonoids Isovitexin (ISO) and 2-Phenylchromone (2PHE) with the HSA, using experimental techniques of fluorescence, UV-Vis absorbance, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectroscopy; along with computational tools of ab initio calculation, molecular dynamics, and molecular modeling. The integration of these experimental and computational approaches allows to characterize the formation of the HSA-flavonoids complexes, determining physicochemical aspects, sucha as: affinity constants, thermodynamic parameters, number of binding sites, cooperativity profile and aminoacid residues responsable for the protein-flavonoids interactions (hydrophobic and electrostatic).Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Interaction between iron ion and dipole carbon monoxide inside spherical cavities

The interactions that occur within hemeproteins are important for biological systems and they are of interest for understanding living systems. In this way, it is important to know the vibrational and electrostatic interactions in this system. In this article, a study is made using a new approach to describe the interaction between iron ions and carbon monoxide inside spherical cavities that mimic volumes of protein cavities in three different media (vacuum, water and ice). We use an alternative trial wavefunction as an ansatz in the Variational Method for the calculation of the energy for a confined ion–dipole system. This trial function is inspired by Supersymmetric Quantum Mechanics. One of the results obtained is the value of the ground state energy of this interaction in a vacuum inside a spherical cavity of radius approximately equal to 12 Bohr radius obtained by the Variational Method. This result is compared with the energy value obtained by the second order Moller–Plesset perturbative method and there is a difference of approximately 1.9 10$$^{-3}$$ hartree (3.87$$\%$$)

Effect of modified clays on the structure and functional properties of biofilms produced with zein

The purpose of this study was to evaluate changes in the structure and some functional properties of biofilms added with modified clays (Cloisite® 15A and Cloisite® 30B) prepared by the casting method. The analysis of the microstructure of the films, scanning electron microscopy (SEM), Optical microscopy (MO), and Infrared Spectroscopy (FTIR) indicated that the addition of clay in the films resulted in the formation of a heterogeneous microstructure, microcomposite or tactoid. Due to the formation of a microcomposite structure, functional properties of the films added with both clays such as opacity, solubility, and permeability to water vapor (PVA), were not better than those of the control film. Thus, it was concluded that although it is possible to produce a film added with modified clays using the casting method, it was not possible to obtain intercalation or exfoliation in a nanocomposite, which would result in improved functional properties

Effect of modified clays on the structure and functional properties of biofilms produced with zein Efeito das argilas modificadas na estrutura e propriedades funcionais de biofilmes produzidos com zeína

The purpose of this study was to evaluate changes in the structure and some functional properties of biofilms added with modified clays (Cloisite® 15A and Cloisite® 30B) prepared by the casting method. The analysis of the microstructure of the films, scanning electron microscopy (SEM), Optical microscopy (MO), and Infrared Spectroscopy (FTIR) indicated that the addition of clay in the films resulted in the formation of a heterogeneous microstructure, microcomposite or tactoid. Due to the formation of a microcomposite structure, functional properties of the films added with both clays such as opacity, solubility, and permeability to water vapor (PVA), were not better than those of the control film. Thus, it was concluded that although it is possible to produce a film added with modified clays using the casting method, it was not possible to obtain intercalation or exfoliation in a nanocomposite, which would result in improved functional properties.<br>O propósito deste estudo foi avaliar mudanças na estrutura e em algumas propriedades funcionais de biofilmes de zeína adicionados de argilas modificadas (Cloisite® 15A e Cloisite® 30B) elaborados pela técnica casting. Por meio do uso de técnicas de análise de microestrutura dos filmes, Microscopia Eletrônica de Varredura (MEV), Microscopia Ótica (MO) e Espectroscopia no Infravermelho (FTIR), observou-se que os acréscimos de argilas resultaram na formação de uma microestrutura heterogênea, formando um microcompósito ou tactoide. Devido à formação da estrutura tipo tactoide, as propriedades funcionais de opacidade, solubilidade e permeabilidade ao vapor d'água (PVA), para os filmes adicionados de argilas, não foram melhores do que as obtidas para o filme controle. Assim, concluiu-se que é possível elaborar um filme adicionado de argilas modificadas usando a técnica casting, porém não foi possível obter intercalação ou esfoliação em nanocompósito, os quais resultariam em melhores propriedades funcionais

Biophysical and flavonoid-binding studies of the G protein ectodomain of group A human respiratory syncytial virus

The human Respiratory Syncytial Virus (hRSV) is the major causative agent of lower respiratory tract diseases in infants, young children and elderly. The membrane protein G is embedded in the viral lipid envelope and plays an adhesion function of the virus to host cells. The present study reports the production of the group A hRSV recombinant G protein ectodomain (edG) and its characterization of secondary structure and thermal unfolding by circular dichroism (CD), as well as the binding investigation of flavonoids quercetin and morin to this protein by fluorescent quenching. CD data reveal that edG is composed mostly of β-structure and its melting temperature is of 325 K. Fluorescence quenching experiments of hRSV edG show that the dissociation constants for the flavonoids binding are micromolar and the binding affinity for the edG/quercetin complex is inversely dependent on rising temperature while is directly dependent for the edG/morin interaction. The thermodynamic parameters suggest that hydrophobic contacts are important for the edG/morin association while van der Waals forces and hydrogen bonds contribute to the stabilization of the edG/quercetin complex. Thus, data reported herein may contribute to the development of new treatment strategies that prevent the viral infection by hRSV

A comprehensive evolutionary scenario for the origin and neofunctionalization of the Drosophila speciation gene Odysseus ( OdsH )

International audienceAbstract Odysseus (OdsH) was the first speciation gene described in Drosophila related to hybrid sterility in offspring of mating between D. mauritiana and D. simulans. Its origin is attributed to the duplication of the gene unc-4 in the subgenus Sophophora. By using a much larger sample of Drosophilidae species, we showed that contrary to what has been previously proposed, OdsH origin occurred 62 million years ago. Evolutionary rates, expression and transcription factor binding sites of OdsH evidence that it may have rapidly experienced neofunctionalization in male sexual functions. Furthermore, the analysis of the OdsH peptide allowed the identification of mutations of D. mauritiana that could result in incompatibility in hybrids. In order to find if OdsH could be related to hybrid sterility, beyond Sophophora, we explored the expression of OdsH in D. arizonae and D. mojavensis, a pair of sister species with incomplete reproductive isolation. Our data indicated that OdsH expression is not atypical in their male-sterile hybrids. In conclusion, we have proposed that the origin of OdsH occurred earlier than previously proposed, followed by neofunctionalization. Our results also suggested that its role as a speciation gene might be restricted to D. mauritiana and D. simulans