Interaction of amphiphilic bioactive molecules with model lipid membranes

MARIA LAURA FANANI

Salto

Congreso; Latin American Crosstalk in Biophysics and Physiology (ISBN 978-987-27591-4-8); 2015

Sociedad Argentina de Biofísica y Seccional Biofísica de la Sociedad Uruguaya de Biociencias

The present work is an overview about the experimental approach of the main questions that as been investigated in our laboratory during the last years: which are the membranes physical properties that are important in controlling the incorporation of amphiphilic bioactive molecules? How the incorporation of those amphiphilic molecules affects in turn the membrane properties? and... are those effects related to biological function? Those questions will be revised for three different amphiphilic molecules: the enzyme Sphingomyelinase,1 the pore-forming toxin Sticholysin2 and the antioxidant drug family L-ascorbic acid alkyl esters.3 The experimental evidences was achieved mainly by using lipid monolayers as model lipid membranes since it allows the control and monitoring of both the rheological properties (compressibility and lateral diffusion of components) and visualization of lateral structure of the lipid films (by fluorescence and Brewster angle microscopy). The electrostatic properties, phase state and general rheology appear as key regulatory points for the insertion of those amphiphilic molecules, showing as a general rule a more favourable insertion to fluid membranes. On the contrary, the presence of lipid domains affects the diffusion and connectivity of the lipid components but no enhancement of the adsorption of the bioactive amphiphiles on the domain borders has been detected. In turn, the incorporation of some bioactive amphiphiles modifies the properties of the membrane and induces lateral reorganization of the membrane structure through phase separation and domain formation.1 Fanani, M.L.; Hartel, S.; Maggio, B.; De Tullio. L.; Jara, J.; Olmos, F.; Oliveira, R.G. Biochim. Biophys Acta 2010, 1798, 1309-1323.2 Pedrera, L.; Fanani, M. L.; Ros, U.; Lanio, M.E.; Maggio, B.; Alvarez, C. Biochim Biophys Acta 2014, 1838, 1752-1759.3 Mottola, M.; Vico, R. V.; Villanueva, M.E.; Fanani, M.L. J Colloid Interface Sci. 2015, 457, 232-242.This work was supported by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), and the General Secretary of Science and Technology of Universidad Nacional de Córdoba (SECyT-UNC), Argentina. MLF also thanks Dr. Bruno Maggio for his enriching discussions and unconditional support.