ジャーナル: Nature / 年: 2014 タイトル: Structure of a modular polyketide synthase. 著者: Somnath Dutta / Jonathan R Whicher / Douglas A Hansen / Wendi A Hale / Joseph A Chemler / Grady R Congdon / Alison R H Narayan / Kristina Håkansson / David H Sherman / Janet L Smith / Georgios Skiniotis / 要旨: Polyketide natural products constitute a broad class of compounds with diverse structural features and biological activities. Their biosynthetic machinery, represented by type I polyketide synthases ...Polyketide natural products constitute a broad class of compounds with diverse structural features and biological activities. Their biosynthetic machinery, represented by type I polyketide synthases (PKSs), has an architecture in which successive modules catalyse two-carbon linear extensions and keto-group processing reactions on intermediates covalently tethered to carrier domains. Here we used electron cryo-microscopy to determine sub-nanometre-resolution three-dimensional reconstructions of a full-length PKS module from the bacterium Streptomyces venezuelae that revealed an unexpectedly different architecture compared to the homologous dimeric mammalian fatty acid synthase. A single reaction chamber provides access to all catalytic sites for the intramodule carrier domain. In contrast, the carrier from the preceding module uses a separate entrance outside the reaction chamber to deliver the upstream polyketide intermediate for subsequent extension and modification. This study reveals for the first time, to our knowledge, the structural basis for both intramodule and intermodule substrate transfer in polyketide synthases, and establishes a new model for molecular dissection of these multifunctional enzyme systems.
全体 : 5th module from Pikromycin biosynthetic pathway (PikAIII) with ph...
全体
名称: 5th module from Pikromycin biosynthetic pathway (PikAIII) with phosphopantetheinylated ACP
要素
試料: 5th module from Pikromycin biosynthetic pathway (PikAIII) with phosphopantetheinylated ACP
タンパク質・ペプチド: PikAIII
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超分子 #1000: 5th module from Pikromycin biosynthetic pathway (PikAIII) with ph...
超分子
名称: 5th module from Pikromycin biosynthetic pathway (PikAIII) with phosphopantetheinylated ACP タイプ: sample / ID: 1000 詳細: Sample was not frozen prior to loading on the grid. The sample was monodisperse. 集合状態: Dimer / Number unique components: 1