Translational and Rotational Diffusion, and Conformational Dynamics of fd Virus on Freestanding Cationic Lipid Membranes

Abstract

Understanding of the mechanisms of interaction of macromolecules and colloidal particles with lipid membranes is far from complete, and the questions related to the effects of membrane local curvature and bending elasticity of the interacting partners are still largely unsolved. Recently, using single-molecule fluorescence video microscopy we discovered unexpected effects in interaction of single DNA molecules with freestanding cationic lipid membranes [1]. In the present contribution, using the same experimental approach, we investigate how much more rigid negatively charged particles - fd viruses [2] - behave upon electrostatic binding to freestanding cationic lipid membranes. We study the translational and rotational diffusion of fd viruses with the lengths in the range of (1-11)×0.88 μm bound to freestanding membranes and observe the crossover from the 2D membrane-controlled to 3D bulk fluid-controlled diffusion dynamics. For virus particles with lengths >4.4 μm we additionally study the effects of the membrane on their conformations and conformational dynamics.[1] C. Herold, P. Schwille, and E. P. Petrov, Phys. Rev. Lett. 104 (2010) 148102.[2] S. Fraden and Z. Dogic, in: Soft Matter, Vol. 2: Complex Colloidal Suspensions (eds. G. Gompper and M. Schick) Wiley-VCH, Weinheim, 2006, pp. 1–86.