Andrew’s research
 
Honours Project: Development of Model Membrane Systems for Surface-Selective Spectroscopic Techniques Biological membranes perform and regulate a number of important functions in cell life, such as transport regulation and signal transduction. In signal transduction and immune response, a key role is played by the conformation and oligomerisation of biological macromolecules at the cell membrane; signaling networks formed by proteins embedded in the cell membrane are responsible for carrying these signals. Thus, perturbations to protein-protein interactions can cause abnormalities in signaling networks and can lead to disease states such as cancer. It has been suggested that within the cell membrane, cholesterol and sphingolipids spontaneously associate with one another to form platforms for the segregation of proteins and that these segregated microdomains (known as lipid “rafts”) mediate signaling by altering protein-protein interactions and protein conformations. Important information concerning signaling processes can be gathered using surface-sensitive analytical methods. However, physiological cells are extremely complex, multicomponent systems that undergo many dynamic operations and thus a system that can act as a cell membrane mimic is required; one that maintains the key features evident in physiological cells. In my honours project, a model membrane-peptide system was developed that will facilitate investigation through time-resolved evanescent wave-induced fluorescence spectroscopy (TREWIFS), a technique recently developed by our research group. TREWIFS is a sensitive spectroscopic technique that has the ability to provide information on molecular interactions and hence microenvironmental information in close proximity to an interface. Model membranes were formed by deposition of single-component lipid vesicles onto a solid substrate, which rupture to form supported lipid bilayers (SLBs). SLB formation was observed upon various solid substrates and the effects of the choice of buffer and electrolyte were investigated. In addition, the photophysics of a lipid-associating peptide were characterised in solution as a reference for future membrane-peptide studies. PhD Project: Probing Membrane Rafts Using Surface-Selective Spectroscopy My PhD project involves the continuation of the work involved in my honours project; with the model membrane-peptide system investigated using TREWIFS and other surface-specific spectroscopic techniques. Model membrane-peptide systems of varying complexity are to be developed; multi-component lipid bilayers are to be formed and the effects of cholesterol investigated, while various transmembrane and receptor proteins are to be incorporated into the model membrane. back  Surface%20Spectroscopy.htmlSurface%20Spectroscopy.htmlSurface%20Spectroscopy.htmlAndrew%20Rapson.htmlshapeimage_4_link_0shapeimage_4_link_1shapeimage_4_link_2
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Contact Michelle Gee
School of Chemistry
University of Melbourne, VIC 3010 Australia mlgee@unimelb.edu.au