Strep-Tactin Superflow Plus

• Three-fold increase in binding capacity (up to 9 mg/ml)
• Ideal for purification from prokaryotic and eukaryotic systems
• Enables automated purification on any liquid chromatography system
• Minimal influence on protein structure, function, and immunogenicity

The small Strep-tag II (WSHPQFEK) can be used to purify active, native conformation proteins to high purity on Strep-Tactin resins. In addition, it can be used in combination with the His tag in a standardized two-step purification procedure. Strep-Tactin is available as Superflow chromatography resin for larger scale purification (up to 9 mg/ml resin). Strep-Tactin resin is also available in prefilled cartridges for automated purification on liquid chromatography systems.

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).  

Meanwhile, pQE TriSystem His·Strep TriSystem Vectors can be used to express proteins doubly-tagged with a His- and a Strep-tag, which are purified in a two-step affinity procedure.  Sequential Ni-NTA and Strep-Tactin purification steps are standardized, very fast, and deliver ultrapure proteins.

Strep-tagged proteins bind with high affinity and specificity to Strep-Tactin, an engineered form of streptavidin (see table Protein binding capacities of Strep-Tactin matrices). After washing, proteins are eluted using low concentrations of biotin (the natural ligand of streptavidin) or desthiobiotin (a stable, reversibly binding biotin analog, see figure  Binding of Strep-tagged proteins to Strep-Tactin and elution using desthiobiotin). Labeling proteins with the small Strep-tag II enables efficient, standardized purification of recombinant proteins expressed in prokaryotic and eukaryotic systems, and delivers highly pure proteins. In addition, the Strep-tag II is the system of choice in situations where other tags may be unsuitable, e.g., when buffer additives such as EDTA may strip IMAC columns.

Strep-tagged proteins are expressed using the pQE TriSystem Vector and obtained at very high purity from cell lysates using Strep-Tactin Superflow Plus affinity purification procedures. Strep-tagged proteins can be purified using batch or gravity-flow methods, or FPLC-compatible columns can be filled with Strep-Tactin Superflow Plus for purification on liquid chromatography systems. Strep-Tactin Superflow Plus is available in 5 ml cartridges for automated purification on liquid chromatography systems such as the FPLC, ÄkTA, and BioLogic systems, or manual purification using a syringe. For reagents compatible with the Strep-Tactin resins, see table Reagents compatible with the Strep-tag Strep-Tactin interaction.

The C-terminal location of the tag ensures that only full-length proteins are purified. The purification process is highly reproducible, guaranteeing the same high quality protein preparations time after time. Monoclonal Strep-tag antibodies are used to detect Strep-tagged proteins in immunodetection procedures with high sensitivity and specificity.

Strep-Tactin Superflow Plus can be used for efficient and reproducible purification of up to 9 mg Strep-tagged protein per ml resin. Purified proteins can be used for:

• Functional or interaction studies
• Crystallization screening
• Structural analysis
• Generation of antibodies