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DOE OSTI · 1870422

Mapping the catalytic conformations of an assembly-line polyketide synthase module

Cogan, Dillon P.·Zhang, Kaiming·Li, Xiuyuan·Li, Shanshan·Pintilie, Grigore D.·Roh, Soung-Hun·Craik, Charles S.·Chiu, Wah·Khosla, Chaitan
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Abstract

Assembly-line polyketide synthases, such as the 6-deoxyerythronolide B synthase (DEBS), are large enzyme factories prized for their ability to produce specific and complex polyketide products. By channeling protein-tethered substrates across multiple active sites in a defined linear sequence, these enzymes facilitate programmed small-molecule syntheses that could theoretically be harnessed to access countless polyketide product structures. Additionally, using cryogenic electron microscopy to study DEBS module 1, we present a structural model describing this substrate-channeling phenomenon. Our 3.2- to 4.3-angstrom-resolution structures of the intact module reveal key domain-domain interfaces and highlight an unexpected module asymmetry. We also present the structure of a product-bound module that shines light on a recently described “turnstile” mechanism for transient gating of active sites along the assembly line.

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Cogan, Dillon P., Zhang, Kaiming, Li, Xiuyuan, Li, Shanshan, Pintilie, Grigore D., Roh, Soung-Hun, Craik, Charles S., Chiu, Wah, Khosla, Chaitan. 2021-11-05. Mapping the catalytic conformations of an assembly-line polyketide synthase module. https://doi.org/10.1126/science.abi8358

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