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SYPF: Struktur und Dynamik in dünnen Polymerfilmen
SYPF 2: Poster Session
SYPF 2.40: Poster
Donnerstag, 14. März 2002, 09:00–18:00, Poster B
Phosphoinositide Monolayers at the Air/Water Interface — •Carsten Selle1, Undine Dietrich1, Markus Weygand1, Jens Pittler1, Bernd Kohlstrunk1, Kristian Kjaer2, and Mathias Lösche1 — 1University of Leipzig, Institute of Experimental Physics I, Linnestr. 5, D-04103 Leipzig — 2Materials Research Department, Risoe National Laboratory, 4000 Roskilde, Denmark
Phosphoinositides (PIs) represent a minor component but important class of phospholipids occurring in the plasma membrane.
We have measured the x-ray specular reflectivity (XR) and grazing incidence diffration (GID) of stereochemically pure dipalmitoyl phosphatidylinositol (DPPI) and three respective monophosphates (DPPIPs) in monolayers on water and on a physiological buffer at room temperature (20 centigrade degrees) in dependence on the lateral pressure.
Electron density profiles - derived from respective XR curves using a model-free data inversion technique - demonstrate significant differences between monolayers on pure water and buffer solution. To arrive at a more detailed structural characterization of the PI lipids at the aqueous surface we are currently applying a new data inversion algorithm which uses distribution functions to map the spatial organization of submolecular fragments (volume-restricted distribution function, VRDF, model).
It is hoped that such a molecular-scale insight in lipid headgroup organization will help understanding the distinct physiological roles of the PIs. Support by the DFG (SFB 294) is gratefully acknowledged.