Avidin, molecular recognition between

When two molecules need to be non-covalently brought together in the creation of a device, one can exploit the natural interaction between biotin and avidin. Biotin is a cofactor that binds to the protein receptor avidin (or strep-avidin), and the binding constant has been measured to be near 10 - M h This is one of the largest affinities associated with any molecular recognition event, and can be considered irreversible. Avidin is a tetrameric protein that binds four biotins independently. The fact that the protein binds four biotins and has such a large affinity for each, makes this system a powerful tool for assembly processes. 

The specific interaction based on molecular recognition of avidin—biotin provides a facile approach for the immobilization ofbiomolecules on solid-state smface. The avidin (streptoavidin)-based system is ideally suited for the well-controlled immobilization of biomolecules due to the specific and strong interaction between avidin and biotin. Since avidin has a nearly cubic shape with four biotin binding sites grouped in two pairs at opposite ends of the avidin molecule, it has been used for anchoring biotinylated biomolecules such as proteins and DNA thereby acting as a biocompatible linker between biotin and biotinylated biomolecules. 

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