Accession Number : ADA195814

Title :   Electrical Field Dependence of Protein Conformation and Channel Function in Lipid Membranes of Different Compositions.

Descriptive Note : Annual rept. 1 Jul 87-1 Jul 88,

Corporate Author : WEIZMANN INST OF SCIENCE REHOVOT (ISRAEL) DEPT OF MEMBRANE RESEARCH

Personal Author(s) : Miller, Israel R

PDF Url : ADA195814

Report Date : 14 Jun 1988

Pagination or Media Count : 6

Abstract : The objective is to study the effect of electricla fields on the conformation of membrane proteins on their lateral distribution and on their function as channels or as receptors. The research has been conducted in three experimental systems, namely lipid monolayers, lipid bilayers (planar or in ulilamellar vesicles) and in whole biological membranes. The key problem in the current research was the vehavior of membrane component under the influence of transmembrane or tangential fields. The transmembrane electric field affects the structure and the permeability of the membrane as a whole as well as the conformation of specific membrane components and interacting groups. The effect on the properties of monolayers has been inferred from the measured capacitance and permeability of monolayers transferred to the polarized mercury/water interface. Ionic permeability of unilamellar vesicles upon applying transmembrane electric potentials served for monitoring of the interaction between the membrane components and of its field dependence. The change inconformation of specific components or groups was investigated by measuring circular dichoism and infra red spectra. Electric field below electorporation level (100v/cm) were applied on swollen thylakoid vesicles approx 4 micrometers in diameter to induce electrophoretic mobility of the latter has been determined by measuring electrostimulated photoluminescence (EPL) from the accumulated and from the depleted photosystems on the two poles of the field polarized vesicles. Keywords: Ganglioside/choleratoxin interaction, lipid monolayer and bilayer permeability. (KT).

Descriptors :   CAPACITANCE, CHANNELS, CONFORMITY, ELECTRIC FIELDS, ELECTROPHORESIS, FUNCTIONS, INFRARED SPECTRA, INTERACTIONS, INTERFACES, LAYERS, LIPIDS, MEMBRANES, MEMBRANES(BIOLOGY), MERCURY, MOBILITY, MONITORING, PERMEABILITY, PHOTOLUMINESCENCE, POLARIZATION, PROTEINS, TANGENTS, WATER

Subject Categories : Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE