Translocation of Subunit PPSE in Plipastatin Synthase and Synthesis of Novel Lipopeptides

Nonribosomal peptide synthase (NRPS) is a unique molecular assembly mechanism with high hybridity. Its recombination is conducive to the development of novel lipopeptides. However, there are few reports on NRPS subunit recombination of plipastatin at present. In this paper, plipastatin synthase was modified by the forward movement of subunit PPSE and the replacement of the communication-mediating (COM) domain. The results showed that ppsABE, a new assembly line, could synthesize novel lipopeptides such as cycle pentapeptide (C16-18β-OHFA-E-O-cyclo(Y-T-I), and its antimicrobial activity against Rhizopus stolonifer and Staphylococcus aureus was better than that of plipastatin. However, the reactivity of ppsABCE disappeared, but the substitution of COMDppsC/COMAppsD or COMDppsD/COMAppsE for COMDppsC/COMAppsE could restore its activity and conduct the biosynthesis of linear hexapeptide (C16-17β-OHFA-E-O-Y-T-E-A/V) and heptapeptide (C17-18β-OHFA-E-O-Y-T-E-A-I). Collectively, these findings indicated that the COM donor domain at the C-terminus of PPSB could communicate with the COM acceptor domain at the N-terminus of PPSE and that the compatible COM domain is an important tool for communication between nonpartner subunits. Moreover, the integrity and selective compatibility of the COM acceptor domain of subunit PPSE are essential to promote the interaction between PPSE and other subunits. This work further complemented the rules of NRPS subunit recombination and provided a theoretical basis for the development of novel high-efficiency lipopeptides.