Desymmetrization of Cyclodepsipeptides by Assembly Mode Switching of Iterative Nonribosomal Peptide Synthetases.

Nonribosomal peptide synthetases assemble a considerable number of structurally complex peptides of pharmacological importance. This turns them into important biosynthetic machineries for peptide diversification by engineering approaches. To date, manifold reprogramming approaches focus on employing module and domain exchanges, or the engineering of domains responsible for amino acid recognition. In this work, we present an engineering strategy for the manipulation of product assembly modes by fusing iterative fungal cyclodepsipeptide synthetases. The reassignment of terminal condensation domains as canonical condensation domains induces a switch from an exclusively iterative into a mixed linear/iterative peptide assembly mode. In the heterologous host E. coli we thus produced in vivo novel hybrid cyclodepsipeptides with altered structural symmetry. Our findings contribute a new experimental set of nonribosomal peptide synthetase reprogramming to the engineering toolbox for peptide structure diversification.