Strep-tag II is widely used in the fields of protein interaction and affinity purification. There are mainly two types of tags, Strep-tag II (W-S-H-P-Q-F-E-K) and Twin-Strep-tag (S-A-W-S-H-P-Q-F-E-K-G-G-G-S-G-G-G-S-G-G-S-A-W-S-H-P-Q-F-E-K).
The affinity of Streptactin-XT Agarose Beads to the fusion protein containing Strep-tag II is in the nM range, and the affinity to the recombinant protein containing Twin-Strep-tag tag is in the pM range. Therefore, it is possible to purify recombinant proteins containing Strep-tag II/Twin-Strep-tag tags with high selectivity and high affinity.
Streptactin-XT and Streptactin are two products used for protein purification, both of which can be used to bind to fusion proteins with the Strep-tag II tag. Streptactin-XT Agarose Beads is an upgraded product of the Streptactin series for protein purification, which has the following advantages:
1. Streptactin-XT can withstand different buffer conditions and additives, such as high salt, detergents, reducing agents, metal ions, and chelating agents. It can be used for protein purification under denaturing conditions. D-biotin below 50 μM in the sample will not affect the binding of the target protein to Streptactin-XT.
2. After binding to the target protein, this product can be reversibly eluted with an elution buffer for Streptactin-XT containing 50 mM D-biotin, eliminating the need for desthiobiotin and reducing reagent usage.
3. Streptactin-XT Agarose beads can be regenerated and used for more than 30 times with the regeneration buffer for Streptactin-XT without affecting the binding performance. If you need to increase the regeneration intensity, you can use a newly configured 10 mM NaOH. It is recommended to use it for regeneration within 5 times.