Navegando por Palavras-chave "Amphiphilic Antimicrobial Peptides"

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    Interação Entre Peptídeos Com Propriedades Antibacterianas E Membranas Lipídicas:Investigação Por Modelagem Computacional
    (Universidade Federal de São Paulo (UNIFESP), 2017-02-24) Outi, Felipe De Oliveira [UNIFESP]; Fileti, Eudes Eterno [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The antibacterial activity of amphiphilic peptides of the AnK type has been studied, which the letter n represents the alanine residue sequence. Such studies have shown that increasing the length of the polyalanine tail is related to the increase in the bactericidal power of the peptide, that is, A3K showing quite weak bactericidal activity whereas A9K shows the highest activity. In this work we propose the computational investigation of the interaction of AnK peptides (with n = 3, 6, and 9) in contact with two different types of lipid, DPPC and DPPG, representing mammals and bacterial membranes, respectively. The hypothesis to be investigated here is that the polyalanine tail length is directly proportional to the bactericidal power of the peptides. To access relevant information on the interaction between peptide and membrane, molecular dynamics simulations and techniques to calculate the potential of mean force were used to evaluate the energetic, dynamic, structural and thermodynamic properties. Our results elucidate, at the molecular level, the important details of the interaction between the peptides and the biological membrane, and provide a quantitative description of the energy and thermodynamics of the systems investigated. This description discards the hypothesis that the size of the polyalanine tail of the peptide is directly responsible for cell death. In addition, we observed that the simplified infinite dilution model, where a single peptide interacts with the biological membrane, was not sufficient to describe the membrane rupture process, and considerations involving peptide concentration, peptide nanostructures morphology, pH of the solutions, among other physical-chemical factors, should be taken into account.