ジャーナル: Nat Commun / 年: 2023 タイトル: C-N bond formation by a polyketide synthase. 著者: Jialiang Wang / Xiaojie Wang / Xixi Li / LiangLiang Kong / Zeqian Du / Dandan Li / Lixia Gou / Hao Wu / Wei Cao / Xiaozheng Wang / Shuangjun Lin / Ting Shi / Zixin Deng / Zhijun Wang / Jingdan Liang / 要旨: Assembly-line polyketide synthases (PKSs) are molecular factories that produce diverse metabolites with wide-ranging biological activities. PKSs usually work by constructing and modifying the ...Assembly-line polyketide synthases (PKSs) are molecular factories that produce diverse metabolites with wide-ranging biological activities. PKSs usually work by constructing and modifying the polyketide backbone successively. Here, we present the cryo-EM structure of CalA3, a chain release PKS module without an ACP domain, and its structures with amidation or hydrolysis products. The domain organization reveals a unique "∞"-shaped dimeric architecture with five connected domains. The catalytic region tightly contacts the structural region, resulting in two stabilized chambers with nearly perfect symmetry while the N-terminal docking domain is flexible. The structures of the ketosynthase (KS) domain illustrate how the conserved key residues that canonically catalyze C-C bond formation can be tweaked to mediate C-N bond formation, revealing the engineering adaptability of assembly-line polyketide synthases for the production of novel pharmaceutical agents.