Structure Function Analysis of Plant Type III Polyketide Synthases

植物III型聚酮化合物合成酶的结构功能分析

• 批准号: 16510164
• 负责人: ABE Ikuro
• 金额: $ 2.18万
• 依托单位: University of Shizuoka
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16510164/
• 关键词: plant polyketide synthase; chalcone synthase; type III polyketide synthase; structure-function analysis; protein engineering; secondary metabolism; biologically active compounds; unnatural natural products

A growing number of functionally divergent type III polyketide synthases (PKSs), the chalcone synthase (CHS) superfamily enzymes, have been cloned and characterized. In this study, we succeeded in molecular cloning and characterization of novel type III PKSs, pentaketide chromone synthase (PCS) and octaketide synthase (OKS) from aloe (Aloe arborescens). Recombinant PCS expressed in Escherichia coli catalyzed successive condensations of malonyl-CoA to produce a pentaketide, 5,7-dihydroxy-2-methylchromone, while recombinant OKS yielded octaketides, SEK4 and SEK4b, the longest polyketides produced by the structurally simple type III PKS. PCS and OKS share 92% amino acid sequence identity, and maintain the conserved Cys-His-Asn catalytic triad. The most characteristic feature is that the CHS active site residue 197 (numbering in Medicago sativa CHS) is uniquely replaced with Met in PCS and Gly in OKS, respectively. Site-directed mutagenesis revealed that the chemically inert single residue 197 lining the active-site cavity determines the polyketide chain length and the product specificity depending on the size of the side chain.

越来越多的功能不同的III型聚酮酶（PKS），查尔酮合酶（CHS）超家族酶，已被克隆和表征。在这项研究中，我们成功地从芦荟（Aloe arborescens）中克隆和鉴定了新的III型PKSs，pentaketide色酮合酶（PCS）和octaketide合酶（OKS）。在大肠杆菌中表达的重组PCS催化丙二酰辅酶A的连续缩合以产生pentaketide，5，7-二羟基-2-甲基色酮，而重组OKS产生octaketides，SEK 4和SEK 4 b，结构简单的III型PKS产生的最长的聚酮化合物。PCS和OKS具有92%的氨基酸序列同源性，并保持保守的Cys-His-Asn催化三联体。最典型的特征是CHS活性位点残基197（在紫花苜蓿CHS中编号）分别被PCS中的Met和OKS中的Gly唯一地取代。定点诱变表明，化学惰性的单一残基197内衬活性位点腔决定聚酮化合物链的长度和产品的特异性，这取决于侧链的大小。

项目成果

Mechanism and stereochemistry of enzymatic cyclization of 24,30-bisnor-2,3-oxidosqualene by recombinant β-amyrin synthase

• DOI: 10.1021/ja0490368
• 发表时间: 2004-06-09
• 期刊: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
• 影响因子: 15
• 作者: Abe, I;Sakano, Y;Ebizuka, Y
• 通讯作者: Ebizuka, Y

Engineered biosynthesis of plant polyketides: Manipulation of chalcone synthase

• DOI: 10.1021/ol052912h
• 发表时间: 2006-02-02
• 期刊: ORGANIC LETTERS
• 影响因子: 5.2
• 作者: Abe, I;Watanabe, T;Noguchi, H
• 通讯作者: Noguchi, H

Active Site Residues Governing Substrate Selectivity and Polvketide Chain Length in Aloesone Synthase

芦荟酮合酶中控制底物选择性和聚酮化合物链长的活性位点残基

• 发表时间: 2006
• 期刊: FEBS J. 273
• 作者: LAW;T.Watanabe;W.Lou;H.Noguchi
• 通讯作者: H.Noguchi

A Plant Type III Polyketide Synthases that Produces Pentaketide Chromone

一种产生五肽色酮的植物 III 型聚酮化合物合成酶

• 发表时间: 2005
• 期刊: J.Am.Chem.Soc. 127
• 作者: I.Abe^*;Y.Utsumi;S.Oguro;H.Morita;Y.Sano;H.Noguchi
• 通讯作者: H.Noguchi

Chalcone Synthase Superfamily of Type III Polyketide Svnthases from Rhubarb (Rheum nalmatum)

来自大黄 (Rheum nalmatum) 的 III 型聚酮化合物合成酶的查尔酮合成酶超家族

• 发表时间: 2005
• 期刊: Proc.Japan Acad., Ser.B. 81
• 作者: I.Abe*;T.Watanabe;H.Noguchi
• 通讯作者: H.Noguchi