Strep-Tactin®XT is the high affinity variant for the purification of strep-tagged fusion proteins, providing binding affinities in the picomolar range for Twin-Strep-tag® while still maintaining binding reversibility and mild recovery of immobilized proteins.

Rapid, one-step affinity purification of Strep•Tag ® fusion proteins can result in active proteins at greater than 95% purity. In a comparison of affinity tags, the Strep•Tag peptide was shown to provide excellent purification, with good yields, at a moderate cost (1).

Strep-Tactin®XT specifically interacts via the engineered biotin binding pocket with the Strep-tag®II as well as the Twin-Strep-tag® and has the highest affinity for both tags (nm range for Strep-tag®II and pM-range Twin-Strep-tag®).

Strep-Tactin® is a streptavidin variant and can be used for surface coating. It is optimized for the binding of Strep-tag®II and Twin-Strep-tag® fusion proteins but can still capture biotinylated targets.

Highly pure Strep-tag II and Twin-Strep-tag recombinant proteins. Fast purifications with simple elution. Physiological conditions and mild elution preserve target protein activity. Fast and easy regeneration. Compatible with a wide range of detergents, denaturants, and other additives.

Strep-Tactin Superflow Plus allows highly efficient purification of proteins (see figures Efficient purification of Strep-tagged GFP with Strep-Tactin Superflow Plus and Highly specific detection of Strep-tagged proteins in any expression system).

Strep-Tactin®XT has a binding affinity in low pM ranges for the Twin-Strep-tag® still maintaining the binding reversibility, the mild recovery of immobilized proteins and the high purity (> 95 %).

The Strep-tag®II/Strep-Tactin® interaction is compatible with a variety of reagents (see Table 1) making the system attractive for purifing metallo- and membrane proteins, large proteins and protein complexes.

The Strep-tag® purification system is based on the highly selective binding of engineered streptavidin, called Strep-Tactin®, to Strep-tag®II fusion proteins. This technology allows one-step purification of almost any recombinant protein under physiological conditions, thus preserving its biological activity.

Affinity purification of Strep-tagged fusion proteins on resins carrying an engineered streptavidin (Strep-Tactin) has become a widely used method for isolation of protein complexes under physiological conditions. Fusion proteins containing two ...