The pFN2A (GST) Flexi® Vector is designed for use with the Flexi® System, Entry/Transfer (Cat.# C8640), and the Flexi® System, Transfer (Cat.# C8820). The vector contains a T7 promoter for bacterial or in vitro protein expression of a protein-coding region. The vector appends an N-terminal glutathione-S-transferase (GST) coding region that can be used to purify the expressed protein. The GST tag contains a TEV protease site for removal of the tag after purification. The vector also contains the lethal barnase gene for positive selection of the insert, an ampicillin-resistance gene for selection of the plasmid and unique SgfI and PmeI sites that allow easy insertion or transfer of the sequence of interest. Inserts containing a protein-coding region can easily be transferred from the pFN2A (GST) Flexi® Vector to other Flexi® Vectors with different expression options.