Demonstration of starter unit interprotein transfer from a fatty acid synthase to a multidomain, nonreducing polyketide synthase.
Demonstration of starter unit interprotein transfer from a fatty acid synthase to a multidomain, nonreducing polyketide synthase.
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DOI：
10.1002/cbic.201200267
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发表时间：
2012-09-03
期刊：
影响因子：
3.2
通讯作者：
Townsend, Craig A.
中科院分区：
文献类型：
--
作者：
Foulke-Abel, Jennifer;Townsend, Craig A.
起始单元选择是聚酮天然产物生物合成中的核心“编程”事件，也是其结构多样性的重要贡献者。 [1]在真菌中发现的迭代非还原聚酮合酶 (NR-PKS) 中，这项任务是由 N 端起始单元酰基转移酶 (SAT) 结构域执行的。一般来说，这些结构域接受细胞中普遍存在的乙酰辅酶A，以启动聚-β-酮化合物中间体的延伸，并解释“起始单元效应”的经典观察。[2]然而，这种模式的变化是已知的，其中一种专门的脂肪酸合酶（FAS）[2b, 3]或更高还原性的PKS [4]独立地制备结构更复杂的起始单元，该起始单元被选择性地用于启动整体合成。前者的一个实例是黄曲霉毒素途径。[3b, 5] 此处，由酵母样亚基 HexA 和 HexB 组成的 FAS、HexS 为 NR-PKS、PksA 提供 C6 脂肪酰基起始单元 1，以启动黄曲霉毒素 (3) 前体降茄酸蒽酮的生物合成（2，图 1）。 HexS 不仅产生比初级真菌 FAS 短得多的酰基链，而且它似乎与 PksA 组织成一种不寻常的 α2β2γ2 复合物。 [3a] 在哺乳动物中，脂肪酸合酶 (FAS) 是一种七结构域 α2-同二聚体，其硫酯酶 (TE) 结构域产生游离脂肪酸产物。在真菌中，FAS 是一种缺乏 TE 结构域的八结构域 α6β6-杂十二聚体，它使用丙二酰/棕榈酰转移酶 (MPT) 结构域将产物以脂肪酰辅酶 A 硫酯的形式排出。 HexS• PksA 复合物的体外放射化学研究未能表明 C6 单元以游离己酰基辅酶 A 的形式释放，因此暗示（但不能证明）已发生直接通向 PksA 的情况。 UMA 算法 [6] 引导的多域蛋白质解剖已被证明是通过提供用于体外重组的催化能力 PKS 片段来推断单个域功能的有价值的途径。 [2b, 7] 这种“解构”方法用于获得重建 HexS 和 PksA 之间的转酰基作用所需的域组合以进行详细分析。
Starter unit selection is a central “programming” event in the biosynthesis of polyketide natural products and an important contributor to their structural diversity.[1] Among the iterative, non-reducing polyketide synthases (NR-PKSs) found in fungi this task is carried out by an N-terminal starter unit acyl transferase (SAT) domain. Generally these domains accept acetyl-CoA ubiquitously available in cells to initiate elongation of poly-β-ketide intermediates and account for the classical observation of a “starter unit effect.”[2] Variations on this pattern are known, however, where a specialized fatty acid synthase (FAS)[2b, 3] or a more highly-reducing PKS [4] independently prepare a structurally more complex starter unit, which is selectively utilized to prime overall synthesis. An instance of the former is exemplified in the aflatoxin pathway.[3b, 5] Here the FAS, HexS, comprised of yeast-like subunits HexA and HexB provides a C6 fatty acyl starter unit 1 for the NR-PKS, PksA, to initiate biosynthesis of the aflatoxin (3) precursor norsolorinic acid anthrone (2, Figure 1). Not only does HexS generate a much shorter acyl chain than primary fungal FAS but also it appears to organize into an unusual α2β2γ2 complex with PksA.[3a] In mammals fatty acid synthase (FAS) is a seven domain α2-homodimer whose thioesterase (TE) domain yields free fatty acid products. In fungi, FAS is an eight domain α6β6-heterododecamer lacking TE-domains that uses a malonyl/palmitoyl transferase (MPT) domain to eject products as fatty acyl-CoA thioesters. In vitro radiochemical studies of the HexS• PksA complex failed to show that the C6 unit was released as free hexanoyl-CoA, thus implying, but not proving, that direct channeling to PksA had occurred. Multidomain protein dissection guided by the UMA algorithm [6] has been shown to be a valuable avenue for deducing individual domain function by providing catalytically competent PKS fragments for in vitro reassembly.[2b, 7] This “deconstruction” approach was employed to obtain the domain combinations necessary to reconstruct transacylation between HexS and PksA for detailed analysis.
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DOI：
10.1038/nrmicro2465
发表时间：
2010-12
期刊：
Nature reviews. Microbiology
影响因子：
--
作者：
通讯作者：
--
影响因子：
15
作者：
Zhou, Hui;Qiao, Kangjian;Gao, Zhizeng;Meehan, Michael J.;Li, Jesse W. -H.;Zhao, Xiling;Dorrestein, Pieter C.;Vederas, John C.;Tang, Yi
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Tang, Yi
影响因子：
2.9
作者：
Quadri, LEN;Weinreb, PH;Walsh, CT
通讯作者：
Walsh, CT
影响因子：
--
作者：
Watanabe, CMH;Townsend, CA
通讯作者：
Townsend, CA
影响因子：
56.9
作者：
Jenni, Simon;Leibundgut, Marc;Ban, Nenad
通讯作者：
Ban, Nenad