Regensburg 2010 – scientific programme

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BP: Fachverband Biologische Physik

BP 31: Posters: Membranes and Vesicles

BP 31.6: Poster

Thursday, March 25, 2010, 17:15–20:00, Poster B1

An in-house x-ray scattering study of membrane fusion intermediates: Sample environment and the effect of cholesterol — •Tobias Reusch, Sebastian Aeffner, Britta Weinhausen, and Tim Salditt — Institute for X-ray Physics, Göttingen, Germany

We have developed an x-ray scattering setup which allows to study membrane fusion intermediates or other nonlamellar lipid mesophases by laboratory-scale x-ray sources at quasi arbitrary degrees of hydration.

We report results of a study of pure lipid bilayers and phospholipid/cholesterol binary mixtures. Stalks, putative intermediate structures occurring during the membrane fusion process, can clearly be identified from reconstructed electron density maps. The choice of phases corresponding to the observed diffraction peaks can be narrowed down substantially by the application of the swelling method.

Phase diagrams of the lyotropic phase behavior of DOPC/cholesterol and DPhPC/cholesterol samples are presented. If cholesterol is present in moderate concentrations, it can substantially promote the formation of stalks at higher degrees of hydration or lower osmotic pressure respectively.