National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM079429
米国
引用
ジャーナル: Science / 年: 2021 タイトル: Mapping the catalytic conformations of an assembly-line polyketide synthase module. 著者: Dillon P Cogan / Kaiming Zhang / Xiuyuan Li / Shanshan Li / Grigore D Pintilie / Soung-Hun Roh / Charles S Craik / Wah Chiu / Chaitan Khosla / 要旨: 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 ...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. 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.