Self-assembly of linear aggregates on curved membranes

¹ Faculty of Electrical Engineering, University of Ljubljana Tržaška 25, 1000 Ljubljana, Slovenia
² University College for Health Care, University of Ljubljana Poljanska 26a, 1000 Ljubljana, Slovenia
³ Department of Physics, North Dakota State University Fargo, ND 58105-5566, USA

Received: 22 November 2004
Accepted: 27 April 2005

Abstract

Recent experiments evidence the strong influence that linear aggregation of beta-sheet peptides can have on the conformation and stability of lipid membranes. We have therefore studied in the dilute limit the self-assembly of one-dimensional aggregates bound to a fluid-like membrane of prescribed curvatures. Each aggregate is characterized by its persistence length and an interaction potential with the membrane. For strong adsorption of flexible aggregates the bending stiffness of the composite membrane grows linearly with the total concentration of aggregate-forming units. For weak adsorption of rigid aggregates the dependence is cubic for which we show —based on a hydrophobic matching hypothesis— that the aggregates can significantly contribute to or even dominate the bending stiffness. We also show how the membrane curvature affects the orientational and size distribution of the aggregates.