Development of biotechnologies for membrane protein study
Abstract
The objectives of this research are for development of biotechnologies, which are to provide new information about physical and chemical properties of supported lipid layer and to facilitate membrane protein study. The structural and chemical properties of lipid monolayers assembled on hydrophobic surfaces through the adsorption of lipid vesicles composed of dioleoylphosphatidylglycerol (DOPG) and dioleoylphosphatidylcholine (DOPC) were studied with a surface plasmon resonance (SPR) spectrometer and atomic force microscope (AFM). The surface density of the lipid molecules in the monolayers was measured with the SPR spectrometer and was found to be strongly dependent on salt concentration of the solution and weakly dependent on the DOPG content of the vesicles. The salt concentration dependence of the surface charge of the lipid monolayers was measured with the AFM and used to determine the density of DOPG in the monolayer. The DOPG content in the monolayer was found to be strongly dependent on the salt concentration of the environment and weakly dependent on the DOPG content of the vesicles. The DOPG composition of the monolayers appears to be determined by a re-equilibration of DOPG during and after adsorption of the vesicles on the surface in a manner that is highly dependent on the ionic concentration of the environment. It was demonstrated in this study that the microreactor arrays with a microfluidic device could be used for high throughput screen of membrane protein function. As a model membrane peptide, gramicidin was used in this study. The gramicidin embedded lipid vesicles were immobilized on the surface in the microreactor structure by controlling the volume in the microreactor. By dispensing acidic drops into the reactor, the gramicidin function was monitored. The technique developed in this research also has a great potential to be used for discovery of drugs.
Degree
Ph.D.
Advisors
Lee, Purdue University.
Subject Area
Biophysics
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