The Strep-tag® story
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- Undisturbing short tag
- Rapid one-step purification under physiological conditions
- Unsurpassed purity and bioactivity
Being one of the foremost providers of expression cloning and protein purification technology in the post genomic era, IBA has developed a universal platform called Strep-tag®. This platform for the rapid and cost effective as well as versatile production and use of recombinant proteins was developed in close cooperation with Prof. Dr. Arne Skerra, TU Munich. In addition to our large product portfolio around Strep-tag, we also provide exclusive custom protein production using this technology.
The basis for the development of the Strep-tag principle was the well known binding of biotin to streptavidin. To take advantage of this strong interaction in protein purification applications we found it desirable to have a peptide that is capable of binding to the biotin binding pocket of streptavidin when fused to recombinant proteins. This peptide was supposed to serve as purification tag. Finally, we succeeded in engineering a short sequence consisting of only 8 amino acids (Trp-Ser-His-Pro-Gln-Phe-Glu-Lys) and named it Strep-tag II.
To optimize binding properties, also streptavidin has been engineered to obtain Strep-Tactin. Thus, the optimal binding partners have been found: The Strep-tag / Strep-Tactin system is now one of the most widely used affinity chromatography systems.
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Strep-Tactin coupled to various matrices allows affinity purification of Strep-tag fusion proteins under physiological conditions. In contrast to other tags, these mild purification parameters preserve bioactivity of the protein and may yield over 99% purity after a single chromatographical step (for example click here).
Using a simple and universal cloning strategy provided by the IBA expression vectors, Strep-tag can be genetically fused to a protein's N- or C-terminal end (see vectors.). In addition, the Strep-tag can also be used in the context of other expression systems (incl. mammalian systems). Detection systems based on Strep-Tactin directly conjugated to reporter enzymes or antibodies are fast, selective and sensitive. Furthermore, the specific interaction enables the selective and oriented immobilization of the target protein on Strep-Tactin coated surfaces. Thus, microplates coated with Strep-Tactin are a general platform for straightforward assays of tagged target proteins, in particular for high throughput screening assays. |
The tag
- Just 8 amino acids
- Balanced amino acid composition - generally no effect on protein structure or activity
- Highly selective and easily controllable binding properties
- C- or N-terminal fusion
- Removal not required
The technology
- Efficient and versatile bacterial expression vectors with standardized cloning strategy
- Affinity chromatography under physiological conditions
- Column regeneration and activity status is visualized by color change (see below)
- Over 99% purity can be achieved
The proteins
Strep-tag is the method of choice for:
- metalloproteins
- membrane proteins
- sensitive protein complexes with multiple subunits
- and any other protein (see examples and references)!
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The Strep-tag protein purification cycle
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