•E. coli expression vectors•

In the Protein Structure Factory, expression vector are used that equip the target proteins with short affinity peptide tags on C- and N-terminus (pQStrep2 and pQStrep4). These affinity tags allow for purification of proteins via two consecutive steps of affinity purification. Six consecutive histidines fused to a target protein (histidine tag) allow for purification by metalchelate affinity chromatography. The Strep tag II consists of eight amino acids which bind to streptavidin and permit affinity chromatography with immobilized variants of this protein. The vectors pGEX-6p1 and pQTEV are currently used to produce tag-free proteins. With pGEX-6p1 and pQTEV, fusion proteins of glutathione S-transferase (GST) or a histidine tag are produced. The vectors encode recognition sequences for specific proteases, the protease 3C from a picornavirus (“PreScission”) and a protease from tobacco etch virus (TEV), that allow for removal of affinity tags from the synthesized proteins.

The helper plasmid pSE111 is used in combination with expression vectors to overexpress the lac repressor and a rare arginine tRNA.

pQE30NST is the vector of the cDNA expression library hEx1 (RZPD library no. 800).

Vectors are available from the Protein Structure Factory.

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© 2003 by V. Sievert, Konrad Büssow last changed 12 Sep 2006