Influence of dengue fusion peptide in Langmuir monolayers and model bilayers

Abstract

The possibility to study functioning mechanisms and the complexity of a biological system using self-organized systems is of great interest in the scientific community. A major part of the biological processes take place at the biological membrane interface and its modeling with Langmuir monolayers and lipid bilayers are valuable because of their easy preparation and molecular control. The development of methods that allow a direct characterization at the molecular level opens a new way to study, for example, systems involving the basic mechanism of virus entry into host cells by membrane fusion process. Studies involving membrane fusion suggest that Dengue virus has access to the host membrane by fusion via the so-called fusion peptide, forming a single membrane. Currently, Dengue virus represents a serious case of public health in Brazil; until April this year, more than thirty thousand cases of Dengue were confirmed only in São Paulo city. The constant changes of the virus make advances of new drugs and vaccines to combat this disease a challenge to the scientific community. Studies in mechanisms of action for improved protocols in the treatment and achievement of new drugs to combat the dissemination of the virus are increasingly necessary. In this project we intend to investigate the behavior of the fusion peptide from Dengue virus (FLAg) in Langmuir monolayers in different lipid composition. We will use Brewster angle microscopy (BAM) and surface infrared spectroscopy (PM-IRRAS) as monolayers characterization techniques in order to observe changes in lipid packing caused by adsorption of the peptide into the monolayer, possible formation of domains and phase separations. Adsorption kinetics experiments will reveal how the peptide incorporates at the interface. Furthermore, we will monitor the FLAg-induced fusion between giant unilamellar vesicles (GUVs) through combination of confocal microscopy observation with FRET assays (Foster resonance energy transfer). (AU)