Recombinant streptomyces avidinii Streptavidin protein

Streptavidin, a tetrameric protein secreted by Streptomyces avidinii, binds tightly to a small growth factor biotin. It finds wide use in molecular biology through its extraordinarily strong affinity for the vitamin biotin; the dissociation constant (Kd) of the biotin-streptavidin complex is on the order of ~10-15 mol/L. The high affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. Recombinant His tagged streptavidin was expressed in E. coli and purified by using conventional chromatography techniques.