Freitag vormittags Vorträge - Bunsentagung - Technische Universität ...

Samstag 22.05.2004, 09:10 Uhr
Vortrag - Hauptthema
A
47
Diffusion in inhomogenous lipid monolayers as
models for lipid raftmembranes
Carsten Selle 1 , Florian Rückerl 1 , Natalie Bordag 1 , Marlis
Wilke 1 , Douglas S. Martin 2 , Martin B. Forstner 2 , Josef A.
1 ,2
Käs
1 Fakultät fuer Physik und Geowissenschaften, Universität
Leipzig
2 University of Texas at Austin
Lateral diffusion within membranes plays an important role for
essential cellular processes as, e.g., membrane formation and
inter- / intracellular signaling. We model the diffusion of a protein
- represented by a charged polystyrene latex - within a
biomembrane with spatial inhomogeneities - e.g. lipid rafts -
constituted by a lipid monolayer at the air-water interface on
an expanded scale. To obtain data about this diffusion process
the motion of carboxylated polystyrene latexes within simple
lipid monolayers (pure (i) dimyristoyl phosphatidylethanolamine,
DMPE and (ii) methyl palmitate) on aqueous subphases has
been tracked. We observed that the diffusion of single particles
is apparently influenced by the presence of condensed domains.
Presumably, dipolar interactions between the domains
and the charged particles induce this behavior. This diffusive
motion was qualitatively modeled by Monte Carlo simulations.
Furthermore, we synthesized the antimicrobial peptide gramicidin
S in order to perform investigations on the effect of this
peptide on the phase behavior of monolayers from various lipids
and lipid mixtures at the air-water interface. In another series
of experiments, the diffusion of polystyrene latexes within
monolayers comprising gramicidin S has been studied.