Modular Oxime Formation by a trans-AT Polyketide Synthase.
Minas, H.A., Francois, R.M.M., Hemmerling, F., Fraley, A.E., Dieterich, C.L., Rudisser, S.H., Meoded, R.A., Collin, S., Weissman, K.J., Gruez, A., Piel, J.(2023) Angew Chem Int Ed Engl 62: e202304481-e202304481
- PubMed: 37216334 
- DOI: https://doi.org/10.1002/anie.202304481
- Primary Citation of Related Structures:  
8ODW - PubMed Abstract: 
Modular trans-acyltransferase polyketide synthases (trans-AT PKSs) are enzymatic assembly lines that biosynthesize complex polyketide natural products. Relative to their better studied cis-AT counterparts, the trans-AT PKSs introduce remarkable chemical diversity into their polyketide products. A notable example is the lobatamide A PKS, which incorporates a methylated oxime. Here we demonstrate biochemically that this functionality is installed on-line by an unusual oxygenase-containing bimodule. Furthermore, analysis of the oxygenase crystal structure coupled with site-directed mutagenesis allows us to propose a model for catalysis, as well as identifying key protein-protein interactions that support this chemistry. Overall, our work adds oxime-forming machinery to the biomolecular toolbox available for trans-AT PKS engineering, opening the way to introducing such masked aldehyde functionalities into diverse polyketides.
Organizational Affiliation: 
Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Vladimir-Prelog-Weg 4, 8093, Zürich, Switzerland.