Enzymatic Synthesis of 1,3,6,8-Tetrahydroxynaphthalene Solely from Malonyl Coenzyme A by a Fungal Iterative Type I Polyketide Synthase PKS1

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• 作者：Isao Fujii ; Yuichiro Mori ; Akira Watanabe ; Yasuyuki Kubo ; Gento Tsuji ; and Yutaka Ebizuka
• 刊名：Biochemistry
• 出版年：2000
• 出版时间：August 1, 2000
• 年：2000
• 卷：39
• 期：30
• 页码：8853 - 8858
• 全文大小：112K
• 年卷期：v.39,no.30(August 1, 2000)
• ISSN：1520-4995

文摘

The Colletotrichum lagenarium PKS1 gene encoding iterative type I polyketide synthase of1,3,6,8-tetrahydroxynaphthalene (T4HN) was overexpressed in Aspergillus oryzae. SDS-PAGE analysisof the cell-free extract prepared from the transformant showed an intense band of 230000 which corresponded to the molecular weight of the deduced PKS1 protein. By using this cell-free extract, in vitrosynthesis of T4HN was successfully confirmed as the first example of the fungal multi-aromatic ringpolyketide synthase activity ever detected. To identify the starter unit for T4HN synthesis, ¹⁴C-labeledacetyl CoA and/or ¹⁴C-labeled malonyl CoA were used as substrates for T4HN synthase reaction. Observedwas the incorporation of ¹⁴C label into T4HN solely from malonyl CoA even in the absence of acetylCoA and not from acetyl CoA. This in vitro result unambiguously identified that malonyl CoA serves asthe starter as well as extender units in the formation of T4HN by fungal polyketide synthase PKS1.