Science
AFM-studies on Solid Supported Lipid-bilayers with Bound Proteins
Proteins are involved in all processes which are necessary for living, e.g. they are responsible for growth and cleavage of cells, which makes them an interesting topic for science and medical application. Small GTPases, like Ras, are GTP-binding proteins involved in cellular processes, e.g. vesicle transport, cell cycles, nuclear import and signal transduction. GTPases act as molecular switches, which cycle between a GDP-bound inactive and a GTP-bound active state regulated through different factors. In oncogenic mutants of Ras this regulation is disturbed. Most small GTPases are associated with membranes within the cell. The association with the lipid membrane is achieved by posttranslational added lipidanchors at N- or C- terminus, mostly containing farnesyl-residues.
In this study our first AFM-studies on solid supported lipid-bilayers with bound proteins are shown. Considering the protein Ras, so far most investigations were done without membrane. We want to study the protein in its natural environment bound to a lipid-bilayer, in order to get a more detailed view of the function of GTPases within the cell. Furthermore we want to observe the interaction between GTPases and its interacting proteins. Therefore the aim of the project is to combine spectroscopic methods like trFTIR-Spectroscopy with imaging methods like Atomic Force Microscopy and Confocal Raman Microscopy. By means of time-resolved Fourier-transform infrared (trFTIR) spectroscopy detailed information on reaction mechanisms of proteins can be gained. Especially the method of Attenuated Total Reflection-FTIR-Spectroscopy (ATR-FTIR) enables measurement of proteins in a more in vivo like environment, e.g. Ras bound to a lipid-bilayer. However, ATR-FTIR can only detect the overall changes on the surface without spatial resolution. In order to attain the space-resolved information, e.g. on the distribution of the proteins on a membrane, this method can be combined with Atomic Force Microscopy (AFM), which allows the characterization of the three-dimensional topography and the physical properties of a surface. A further step is possible with Tip Enhanced Raman Scattering (TERS), a technique where the AFM tip provides the surface enhanced effect and molecular information on nanometre scale can be obtained.
This poster was presented at NanoBioViews 2009; 14-15 October 2009: http://www.nanobioviews.net
Click this link to view the complete poster as a PDF
Contact:
Laven Mavarani
LS für Biophysik
Ruhr-Universität Bochum
Universitätsstr.
150
44801 Bochum, Germany
mavarani@bph.rub.de
Authors:
Laven Mavarani
Jörn Güldenhaupt
Carsten Kötting
Klaus Gerwert
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