The vectors below are used for inducible expression of HQ- and GST-tagged fusion proteins in E. coli and cell-free systems using the T7 RNA polymerase promoter. The HQ tag and polyhistidine tag (His) are comparable in their affinity for Ni ions and will bind to all His-binding surfaces and resins. In certain cases the HQ-tagged proteins can be eluted from the affinity columns at lower concentrations of imidazole—a property useful for some downstream applications such as enzymatic reactions. As with His tag, proteins can be expressed from bacterial, insect and mammalian systems and purified under either native or denaturing conditions. The GST tag has been successfully used to boost tagged protein solubility during E. coli expression. The Flexi Vector System is a simple, directional cloning method for protein-coding sequences. It is based on two rare-cutting restriction enzymes, SgfI and PmeI, and provides a rapid, efficient and high-fidelity way to transfer protein-coding regions between a variety of Flexi Vectors without the need to resequence. Direct transfers can only occur between two N-terminal tagged vectors or from an N-terminal to a C-terminal vector. pFN2A/K (GST) Flexi Vectors are designed for protein expression with an N-terminal GST tag in E. coli and T7 cell-free expression systems. pFN6A/K (HQ) Flexi Vectors are designed for protein expression with an N-terminal HQ tag in E. coli and T7 cell-free expression systems. pFC7A/K (HQ) Flexi Vectors are designed for protein expression with an C-terminal HQ in E. coli and T7 cell-free expression systems. pF1A/K T7 Flexi Vectors (Cat.# C8441, C8451) are designed for inducible expression of native untagged protein. Note: Flexi Vectors contain the lethal barnase gene to reduce background colonies without inserts during the subcloning procedure. Using the Flexi Vector Cloning System replaces the barnase gene with your insert. These vectors, as purchased, cannot be cultured in normal laboratory strains of E. coli without an insert.|
Easy to Implement and Reliable: Choose between traditional His-affinity and GST-affinity resins for standard protein purification and prokaryotic expression applications. Cost-Effective: Technology for reusable and cost-efficient Ni (His-affinity) and gluthathione (GST-affinity) resins. Versatile Cloning: Choose from a variety of expression systems and fusion tag orientations and then transfer to others as required (for Flexi(R), system). Time Savings: Barnase insert (Flexi(R), system) decreases the number of background colonies, allowing efficient transfer of genetic constructs.