Discovery of demurilactone A; a novel growth inhibitor of L-form Bacillus Subtilis Yousef Dashti 1 , Fatemeh Mazraati Tajabadi 2 , Ling Juan Wu 1 , Alexander Escasinas 2 , Nicholas Edward Ellis Allenby 2 , Jeff Errington 1,2 1 Newcastle University, UK, 2 Odyssey Therapeutics Inc, UK Metabolic profiling of the extracts from a library of actinobacteria of Demuris Ltd. led to identification of novel polyketide demurilactone A produced by Streptomyces strain DEM21308. The structure of the compound was assigned based on detailed investigation of 1D/2D NMR spectra and HR-MS. Whole genome DNA sequencing followed by bioinformatics analysis, identified type I polyketide synthases encoded by dml gene cluster to direct the biosynthesis of this polyene macrolide. While the number of modules is consistent with the carbon backbone of the assigned structures, some discrepancies were identified in the domain organization of some modules. Close investigation of the amino acid sequences identified several mutations in the conserved motifs of nonfunctional domains. Furthermore, the absolute configuration of hydroxy bearing stereocenters was proposed based on analysis of ketoreductase domains. Remarkably, although demurilactone A has little detectable activity against normal walled bacteria it specifically inhibits the growth of cell wall deficient “L-form” Bacillus subtilis at an MIC value of 16 μg/ml. Time-lapse microscopy analyses revealed that demurilactone affects membrane dynamics, probably by reducing membrane fluidity. This compound could be a powerful reagent for studying long standing questions about the involvement of L-forms in recurrent infection.
P11
© The Author(s), 2022
Made with FlippingBook Learn more on our blog