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Novel applications of nanobodies
Posted on February 25th, 2010 No commentsCamelid derived single domain peptides are a novel form of antibody which maintain the same antigen binding properties but have greater stability and smaller size than traditional antibody. These molecules can be conjugate with several chromophores, for instance with green fluorescent protein for cellular imaging applications.
A group from the University of Munich (German) applied its deepen knowledge about GFP modifications to nanobodies, this is the name of camelid peptides. The result was an improvement in GFP brightness modulation. By performing a phage display screening, they found out seven different molecules able recognize GFP and enhance or minimize its fluorescent signal. To validate the system, they produced a GFP- tagged oestrogen receptor and a nuclear binding enhancer nanobody, in presence of hormone the receptor moved into the nucleus and GFP signal increased five- fold its brightness. Several applications can be thought for this tool. For instance, nanobodies for each cellular compartment can be useful to determine how the protein of interest tagged with GFP change their position inside the cells in response to specific stimuli. Alternatively, protein- protein interaction can be studied because nanobody can bind one protein and after interaction with the second protein fluorescent signal can be modulated, as well as it should be possible to evaluate the duration of interaction self. A novel and flexible tool is now available for biologists. -
SPR a tool to study protein-protein interactions
Posted on June 8th, 2009 No commentsSurface plasmon resonance (SPR) is the best technique to explore protein- protein interactions. In particular, SPR is important to study multiple interactions simultaneously in a proteomic approach. How does SPR work?
Protein partner, potentially interacting with your protein of interest is bound on gold coated glass slide and a solution containing your protein is flowed across the slide’s surface. When a biomolecule is attached to gold surface, so when your protein and its partner interact, the refractivity of gold changes and different angle of light can be measured. SPR was set up for the first time in 1990, and very big advances have been done for this technology. Now SPR microscopy has been proposed. The novelty of this approach consists on studying protein- protein interactions in a flat array. In this way, it’s possible to save reagents and time and increase the efficiency. Arrays of DNA, peptides, antibodies and carbohydrates are frequently reported. In certain cases aptamers substitute antibodies in order to obtain more robust interaction. The challenge of this technology is choosing the right surface and functionalise it in the best way. In an array spots have to be properly separated but the extension of surface chemistry is totally chosen by researcher and this is a great advantage.
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