Macromolecules and colloids on lipid membranes: Brownian motion, conformational dynamics, and local perturbations
Eugene Petrov
Biotec, TU Dresden

June 14, 2012, 1 p.m.


The plasma membrane is one of the most important units of the cell, not only because it defines the boundaries of cell components and the cell itself, but also because of its functionality. The functionality of the membrane is largely determined by the Brownian motion of lipids, membrane proteins, and membrane domains (rafts). Therefore, in order to properly understand the dynamics of membrane processes, one should understand the laws governing the Brownian motion of membrane inclusions. In this context, I will discuss experimental results on translational and rotational diffusion of micrometer-sized solid domains in two-component lipid membranes, as well as the behavior of negatively charged rod-like fd virus particles and DNA macromolecules weakly adhering to freestanding cationic lipid bilayers. I will show that these experimental observations are in a good agreement with the predictions of a hydrodynamics-based theory for the viscous drag on membrane inclusions. Stronger interactions of macromolecules and colloidal particles with lipid membranes can lead to local lipid demixing and curvature perturbations of the membrane. As an example of such a behavior, I will discuss the recently discovered phenomenon of DNA condensation on freestanding cationic lipid membranes.



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Macromolecules and colloids on lipid membranes: Brownian motion, conformational dynamics, and local perturbations
Eugene Petrov
Biotec, TU Dresden

June 14, 2012, 1 p.m.


The plasma membrane is one of the most important units of the cell, not only because it defines the boundaries of cell components and the cell itself, but also because of its functionality. The functionality of the membrane is largely determined by the Brownian motion of lipids, membrane proteins, and membrane domains (rafts). Therefore, in order to properly understand the dynamics of membrane processes, one should understand the laws governing the Brownian motion of membrane inclusions. In this context, I will discuss experimental results on translational and rotational diffusion of micrometer-sized solid domains in two-component lipid membranes, as well as the behavior of negatively charged rod-like fd virus particles and DNA macromolecules weakly adhering to freestanding cationic lipid bilayers. I will show that these experimental observations are in a good agreement with the predictions of a hydrodynamics-based theory for the viscous drag on membrane inclusions. Stronger interactions of macromolecules and colloidal particles with lipid membranes can lead to local lipid demixing and curvature perturbations of the membrane. As an example of such a behavior, I will discuss the recently discovered phenomenon of DNA condensation on freestanding cationic lipid membranes.



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