Speaker
Prof.
Peter Tieleman
(University of Calgary, Canada)
Description
The thermodynamics of interactions between the lipid bilayer
and other molecules determines to a large extend the
transport rate of these molecules across the bilayer as well
as the nature of the process involved in partitioning. In
the past few years we have studied these interactions for a
range of organic molecules, for lipids, cholesterol,
fullerenes, and models of carbon nanotubes. The large
gradients in density, order, and hydrophobicity in a bilayer
make partitioning a highly non-trivial process that is
difficult to predict. Insertion of polar or charged
molecules in particular involves significant changes in the
bilayer structure, which dominate the cost of partitioning.
An extreme example of this is the partitioning of multiple
arginine side chains into the bilayer, which is a highly
non-additive process with most of the energetic cost
determined by the formation of an initial water defect.
Similar observations are made for transport of lipids.
Coarse-grained simulations of fullerene show little membrane
perturbation, but investigations of nanotubes show
significant and non-trivial effects that depend on the
orientation of the nanotube. The systematic series of
calculations from our lab may be useful in understanding the
transport of functionalized nanoparticles through lipid
membranes as one of the determinants of bioavailability and
toxicity.
References:
W.F.D. Bennett, J.L. MacCallum, D.P. Tieleman. 2009.
Thermodynamic analysis of the effect of cholesterol on
dipalmitoylphosphatidylcholine lipid membranes., J. Am.
Chem. Soc. 131, pp.1972-1978.
J. Wong-Ekkabut, S. Baoukina, W. Triampo, I-M. Tang, D.P.
Tieleman, L. Monticelli. 2008. Computer simulation study of
fullerene translocation through lipid membranes, Nature
Nanotechnology 3, pp. 363 – 368
J.L. MacCallum, D.P. Tieleman. 2008. Interactions between
small molecules and lipid bilayers, Curr. Top. Memb. 60, pp.
227-256
J.L. MacCallum, W.F. D. Bennett, D. P. Tieleman. 2008.
Distribution of Amino Acids in a Lipid Bilayer from Computer
Simulations, Biophys. J. 94, pp. 3393-3404
Primary author
Prof.
Peter Tieleman
(University of Calgary, Canada)
