Streptavidin mutein, immobilized.
Settled resin of 50% suspension Streptavidin Mutein Matrix.
The binding of biotin to avidin/streptavidin is the strongest known noncovalent interaction of biological molecules [(Kd 0.6 x 10-15 M (avidin), 4 x 10-14 M (streptavidin)]. Strong binding provides a great advantage for certain applications of the derived biotin-avidin/streptavidin technology, such as surface immobilization, blotting technologies, immunoassays, cross-linking studies, and histochemistry. However, the use of immobilized avidin/streptavidin for the purification of biotinylated proteins is limited. In this instance, the extreme affinity of the binding partners creates a drawback of enabling elution only under very harsh conditions that usually destroy the functionality of the protein of interest.
Recombinant streptavidin technology was used to screen for a mutant streptavidin with reduced binding affinity toward biotin. By substituting three amino acids, a mutein was obtained with a biotin dissociation constant of 1.3 x 10-7 M.
The Streptavidin Mutein Matrix provides this mutein immobilized onto cross-linked agarose beads in a highly stable and regenerable form, which allows purification of biotinylated proteins that results in excellent purity and recovery.