Objective
Interaction between ion transporting membrane proteins and lipids of the membrane-forming bilayer is assumed to be a general mechanism of protein regulation. To understand the involved mechanisms the project proposes to study the effects of two principal characteristics of the lipid bilayer, the distribution of the electric field in the membrane dielectric and the membrane elasticity, on the function of mechano-sensitive channels and the Na,K-ATPase.
The alteration of the membrane parameters will be caused by adsorption of lipophilic, membrane-active substances (styryl dyes as modificators of the dipole potential, amphiphilic ions, phospholipase), inorganic ions of high affinity to phospholipids (lanthanides) and ions with different chaotropic effects on the membrane surface.
It is planed to measure and analyse quantitatively characteristic properties of membranes of different lipid composition with different techniques on planar lipid bilayer (measurements of boundary potentials, charge relaxation and conductivity in the presence of hydrophobic ions, transversal membrane compressibility), on lipid monolayers (Volta potentials and pressure-area diagrams) and on liposome suspensions (electrokinetic studies, calorimetry, fluorescence). These approaches will be used to obtain information on the structure of ion-conducting pathway of Na,K-ATPase. The effects of local electric fields on the kinetics of charge transfer will be studied by electric measurements on lipid bilayer modified by fragments of cell membrane using the methods developed by authors of the project and by spectral measurements on free fragments with fluorescent dyes.
The results of the studies will be applied to develop physical models of ion transport by Na,K-ATPase and of blocking effects of lanthanides on the mechanosensitive channels.
Topic(s)
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78434 Konstanz
Germany