title: Biophysical characterization of the interaction between M2-1 protein of hRSV and quercetin.
abstract: hRSV is the major causative agent of acute respiratory infections. Among its eleven proteins, M2-1 is a transcription antiterminator, making it an interesting target for antivirals. Quercetin is a flavonol which inhibits some virus infectivity and replication. In the present work, the M2-1 gene was cloned, expressed and the protein was purified. Thermal stability and secondary structure were analyzed by circular dichroism and the interaction with Quercetin was evaluated by fluorescence spectroscopy. Molecular docking experiments were performed to understand this mechanism of interaction. The purified protein is mainly composed of α-helix, with a melting temperature of 328.6K (≈55°C). M2-1 titration with Quercetin showed it interacts with two sites, one with a strong constant association K1 (site 1≈1.5×106M-1) by electrostatic interactions, and another with a weak constant association K2 (site 2≈1.1×105M-1) by a hydrophobic interaction. Ligand's docking shows it interacts with the N-terminus face in a more polar pocket and, between the domains of oligomerization and RNA and P protein interaction, in a more hydrophobic pocket, as predicted by experimental data. Therefore, we postulated this ligand could be interacting with important domains of the protein, avoiding viral replication and budding.
authors.affiliation: Instituto de Biociências, Letras e Ciências Exatas, UNESP Univ Estadual Paulista, Campus São José do Rio Preto, Departamento de Biologia, Brazil; Instituto de Biociências, Letras e Ciências Exatas, UNESP Univ Estadual Paulista, Campus São José do Rio Preto, Centro Multiusuário de Inovação Biomolecular, Laboratório de Biologia Molecular, Brazil. Electronic address: thiago_spt@yahoo.com.br.
authors.forename: Thiago Salem Pançonato
authors.initials: TS
authors.lastname: Teixeira
authors.affiliation: Instituto de Biociências, Letras e Ciências Exatas, UNESP Univ Estadual Paulista, Campus São José do Rio Preto, Departamento de Física, Brazil; Instituto de Biociências, Letras e Ciências Exatas, UNESP Univ Estadual Paulista, Campus São José do Rio Preto, Centro Multiusuário de Inovação Biomolecular, Laboratório de Biologia Molecular, Brazil. Electronic address: ykrocaruso@hotmail.com.
authors.forename: Ícaro Putinhon
authors.initials: ÍP
authors.lastname: Caruso
authors.affiliation: Faculdade de Ciências e Letras, UNESP Univ Estadual Paulista, Campus Assis, Departamento de Ciências Biológicas, Laboratório de Imunologia Celular e Molecular, Brazil. Electronic address: brunorpl@hotmail.com.
authors.forename: Bruno Rafael Pereira
authors.initials: BR
authors.lastname: Lopes
authors.affiliation: Instituto de Biociências, Letras e Ciências Exatas, UNESP Univ Estadual Paulista, Campus São José do Rio Preto, Departamento de Química e Ciências Ambientais, Brazil. Electronic address: luisregasini@gmail.com.
authors.forename: Luis Octávio
authors.initials: LO
authors.lastname: Regasini
authors.affiliation: Faculdade de Ciências e Letras, UNESP Univ Estadual Paulista, Campus Assis, Departamento de Ciências Biológicas, Laboratório de Imunologia Celular e Molecular, Brazil. Electronic address: karinafcla@gmail.com.
authors.forename: Karina Alves de
authors.initials: KA
authors.lastname: Toledo
authors.affiliation: Instituto de Biociências, Letras e Ciências Exatas, UNESP Univ Estadual Paulista, Campus São José do Rio Preto, Departamento de Física, Brazil; Instituto de Biociências, Letras e Ciências Exatas, UNESP Univ Estadual Paulista, Campus São José do Rio Preto, Centro Multiusuário de Inovação Biomolecular, Laboratório de Biologia Molecular, Brazil. Electronic address: mafossey@gmail.com.
authors.forename: Marcelo Andrés
authors.initials: MA
authors.lastname: Fossey
authors.affiliation: Instituto de Biociências, Letras e Ciências Exatas, UNESP Univ Estadual Paulista, Campus São José do Rio Preto, Departamento de Física, Brazil; Instituto de Biociências, Letras e Ciências Exatas, UNESP Univ Estadual Paulista, Campus São José do Rio Preto, Centro Multiusuário de Inovação Biomolecular, Laboratório de Biologia Molecular, Brazil. Electronic address: fatyssouza@gmail.com.
authors.forename: Fátima Pereira de
authors.initials: FP
authors.lastname: Souza
mesh_terms: D000595:Amino Acid Sequence; D055592:Biophysical Phenomena; D019295:Computational Biology; D062105:Molecular Docking Simulation; D011485:Protein Binding; D011487:Protein Conformation; D011794:Quercetin / Q000378:metabolism*; D018113:Respiratory Syncytial Virus, Human; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014764:Viral Proteins; D011794:Quercetin
keywords: Biophysical analyses; M2-1; Molecular docking; Quercetin; hRSV