Artificial binding proteins are also referred to as the next-generation antibodies.1,2 Based on novel scaffold proteins they can circumvent some problems that antibodies are faced with today when applied in fields like medicine or biotechnology. The scaffold proteins can be chosen to:
- be highly thermodynamically stable and free of disulfide bonds
- be easily producible in prokaryotes, e.g. E. coli
have low molecular weight
By protein engineering and evolutionary selection techniques we are able to equip the scaffold proteins with the desired binding specificities. To achieve this we start from creating a protein variant library by randomizing the surface of the scaffold proteins. This either generates a de novo binding patch or alters an existing patch. The library is subsequently screened for binding activity against specific targets by evolutionary selection methods, e.g. ribosome display or phage display. Applications for such selected artificial binding proteins can be found for example in therapy, diagnostics and research.
We aim to integrate optimized existing and novel innovative methods into a complete technology platform
which can then be used for the routine creation of artificial binding proteins. Our work will also give us a deeper insight into molecular principles influencing protein-protein interactions as well as protein folding and stability.
Selection and screening of libraries as well as production and purification of the so-called hit-variants is extremely suited for automation. Optimized automation protocols allow a high through-put in these steps and in return create large amounts of data on biochemical and biophysical properties of selected proteins.
Different selection systems (ribosome display, various phage display methods) are analyzed for selection efficiency and characteristics of the selected binding proteins (affinity, solubility and thermodynamical stability). With the aquired data we are able to optimise the selection procedure.
Chemical and genetical fusion methods are analyzed for advantages and disadvantages in ease of handling, avidity effects and other characteristics.
Scaffolds & Library design
The scaffolds we evaluate and use currently are the human gamma-Crystallin3 and the thermodynamically extremely stable computationally designed protein M7.4,5 Various library formats are developed for selection of artificial binding proteins.