Speaker
Prof.
Luca Monticelli
(INSERM, Paris)
Description
Biological membranes compartmentalize cells and form the
interface between the cell and its environment. Lipid
bilayers are fundamental components of cell membranes. Due
to their fluidity, it is very difficult to obtain
experimentally atomic level structural information on lipid
bilayers in their physiologically relevant state. One
property that is difficult to explore in experiments is the
membrane ability to dissolve different solutes, including
transmembrane peptides and synthetic compounds. We
investigated the solubility of fullerene in lipid bilayers,
and compared it to its solubility in alkanes. Fullerenes and
their derivatives have unique properties that make them
interesting for a number of technological applications.
Moreover, they are biologically active and can enter easily
liposomes and different kinds of cells. Despite numerous
studies on both synthetic and biological systems, it is yet
unclear how these materials interact with lipid bilayers,
and their aggregation in membranes is controversial. I will
present results on the validation of all-atom models for C60
fullerene, and on the development of a coarse-grained (CG)
model compatible with the MARTINI CG force field for lipids
and proteins [1-2]. Using both unbiased and non-equilibrium
MD techniques, we characterize the thermodynamics and the
kinetics of fullerene aggregation in lipid bilayers and in
alkanes. We find that, despite the apparent similarity
between alkanes and the bilayer interior, membranes are much
better solvents for fullerene. Our results are compatible
with experiments showing small perturbations of membrane
properties upon addition of fullerene.
[1] SJ Marrink et al., J Phys Chem B, 111 (2007) 7812
[2] L Monticelli et al., J Chem Theory Comput, 4 (2008) 819
