Figure 4.

Example of the tandem-repeat strategy for high yield peptide production in the pET31b expression vector. A fusion protein comprising ketosteroid isomerase (KSI) is targeted to inclusion bodies in E. coli together with tandem repeat peptides encoding the P₁₁-4 sequence and a His tag. The fusion protein and peptides are cleaved with cyanogen bromide (CNBr), which acts on intervening methionine residues. This results in the presence of a C-terminal homoserine lactone (hsl) on each resulting peptide monomer.