Download MendeleyStructural Basis for Enzymatic Off-Loading of Hybrid Polyketides by Dieckmann Condensation.
Cogan, D.P., Ly, J., Nair, S.K.(2020) ACS Chem Biol
- PubMed: 33017142
- DOI: https://doi.org/10.1021/acschembio.0c00579
- Primary Citation of Related Structures:
6E6T, 6E6U, 6E6Y - PubMed Abstract:
While several bioactive natural products that contain tetramate or pyridone heterocycles have been described, information on the enzymology underpinning these functionalities has been limited. Here we biochemically characterize an off-loading Dieckmann cyclase, NcmC, that installs the tetramate headgroup in nocamycin, a hybrid polyketide/nonribosomal peptide natural product. Crystal structures of the enzyme (1.6 Å) and its covalent complex with the epoxide cerulenin (1.6 Å) guide additional structure-based mutagenesis and product-profile analyses. Our results offer mechanistic insights into how the conserved thioesterase-like scaffold has been adapted to perform a new chemical reaction, namely, heterocyclization. Additional bioinformatics combined with docking and modeling identifies likely candidates for heterocycle formation in underexplored gene clusters and uncovers a modular basis of substrate recognition by the two subdomains of these Dieckmann cyclases.
