Fig. 3

Schematic representation of the expression vectors that contain fusion tags with and without redox properties, which were used for cytoplasmic and periplasmic expression of venom peptides in Escherichia coli. All vectors include a T7 promoter, a ribosome binding site (rbs), a lac operator, a 6HIS tag for nickel affinity purification and a Tobacco Etch Virus (TEV) protease cleavage site. The 6HIS tag is N-terminal for pHTP1 vector (a) and internal for expression vectors including fusion tags (b). pHTP4 (DsbC) and pHTP6 (MBP) carry fusion tags containing a signal peptide (represented in crossed green lines) to target exportation of the fusion protein to the periplasm of E. coli cells. The inactive DsbC fusion partner, which contains two mutations at the catalytic site (C100A and C103A), was inserted into pHTP3 (LLmutDsbC)