Artificial Splitting of a Non-Ribosomal Peptide Synthetase by Inserting Natural Docking Domains

The interaction in multisubunit non-ribosomal peptide synthetases (NRPSs) is mediated by docking domains that ensure the correct subunit-to-subunit interaction. We introduced natural docking domains into the three-module xefoampeptide synthetase (XfpS) to create two to three artificial NRPS XfpS subunits. The enzymatic performance of the split biosynthesis was measured by absolute quantification of the products by HPLC-ESI-MS. The connecting role of the docking domains was probed by deleting integral parts of them. The peptide production data was compared to soluble protein amounts of the NRPS using SDS-PAGE. Reduced peptide synthesis was not a result of reduced soluble NRPS concentration but a consequence of the deletion of vital docking domain parts. Splitting the xefoampeptide biosynthesis polypeptide by introducing docking domains was feasible and resulted in higher amounts of product in one of the two tested split-module cases compared to the full-length wild-type enzyme.