“New insights in membrane fusion: role of surface electrostatic potential

ROSANA CHEHÍN

Buenos Aires

Conferencia; II Jornadas Iberoamericanas de Bioinformática; 2006

Red Iberoamericana de Bioinformática

Membrane fusion is an ubiquitous cell event present in process such as membrane trafficking, exocitosis, virus infection and gamete formation. Lipids membranes do not spontaneously fuse and energy must be invested to overcome hydration repulsion between membranes that approach each other and to disrupt normal bilayer structure of the fusing membranes. Understanding the molecular events that occur in cell membranes upon binding and insertion of fusogenic proteins represents an intriguing challenge. For several proteins it has been demonstrated that non-specific electrostatic and hydrophobic interactions play a major role in their association to lipid bilayers and the segments involved have been identified. In vitro studies demonstrated the ability of some dehydrogenases to induce fusion of liposomes. Glyceraldehide-3-phosphate dehydrogenase has also been involved in fusion events in vivo and its ability to bind to phospholipids monolayers has been studied. In the present communication a comparative study on the ability of several dehydrogenases to associate to liposomes was carried out using fluorescent probes. We also report calculations of the nonspecific electrostatic contribution to the binding of the proteins to membranes. The calculations were carried out with the finite-difference Poisson-Boltzmann method, which has proved accurate in its ability to account for electrostatic of protein-membrane systems. The results provide evidence on the importance of nonspecific electrostatic interactions for the membrane association properties of this group of proteins.