ENGINEERING OF PEPTIDE SYNTHETASES - KEY ROLE OF THE THIOESTERASE-LIKE DOMAIN FOR EFFICIENT PRODUCTION OF RECOMBINANT PEPTIDES

Peptide synthetases are large enzymatic complexes that catalyze the sy nthesis of biologically active peptides in microorganisms and fungi an d typically have an unusual structure and sequence, Peptide synthetase s have recently been engineered to modify the substrate specificity to produce peptides of a new sequence, In this study we show that surfac tin synthetase can also be modified by moving the carboxyl-terminal in trinsic thioesterase region to the end of the internal amino acid bind ing domains, thus generating strains that produce new truncated peptid es of the predicted sequence. Omission of the thioesterase domain resu lts in nonproducing strains, thus showing the essential role of this r egion and the possibility of obtaining peptides of different lengths b y genetic engineering. Secretion of the peptides depends on the presen ce of a functional sfp gene.