Recombinant bioactive peptide examples

Recent examples of the production of bioactive peptides, often antimicrobials, in bacterial and yeast host systems highlight examples of various fusion and cleavage strategies. 

Niu et al. (2008) used the methylotrophic yeast P. pastoris vector pPICZa-A in which transcription of the target protein is controlled by the very 

Chen et al. (2008) have expressed a codon-optimized form of the CM4 peptide in E. coli. In this case, two alternative expression/purification systems were examined namely the widely used glutathione-S-transferase (GST) and a chitin-binding domain (CBD) system with associated intein splicing (New England Biolabs Inc.). The GST system failed to allow recovery of expressed fusion protein. In contrast, the CBD/intein system allowed the recovery of 110 mg/L fusion protein with a final RP-HPLC purification step yielding 2.1 mg/L of pure peptide which displayed antimicrobial activity against E. coli Ki2D3i and Salmonella. 

Another study on expression of an insect cecropin in E. coli used a fusion to the thioredoxin protein (Xu et al., 2007b). In this case the Musca domestica (house fly) cecropin termed Mdmcec was cloned downstream of the thioredoxin with an intervening His-tag for purification and enterokinase (Table 2) cleavage site (bold) for release of peptide 

In this study, Li et al. (2007b) used an E. coli BL21(DE3) host in conjunction with the vector pET32a to express a thioredoxin fusion of the format  

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