Cloning and characterization of an Armillaria gallica cDNA encoding protoilludene synthase, which catalyzes the first committed step in the synthesis of antimicrobial melleolides.
Cloning and characterization of an Armillaria gallica cDNA encoding protoilludene synthase, which catalyzes the first committed step in the synthesis of antimicrobial melleolides.
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DOI：
10.1074/jbc.m110.165845
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发表时间：
2011-03-04
期刊：
影响因子：
--
通讯作者：
Jennewein S
中科院分区：
文献类型：
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作者：
Engels B;Heinig U;Grothe T;Stadler M;Jennewein S
蜜环内酯和相关的真菌倍半萜芳香酯是从蜜环菌属真菌培养物中提取的具有抗菌和细胞毒性的天然产物。所有蜜环内酯生物合成的第一步涉及到普遍存在的倍半萜前体法尼基二磷酸的环化反应，这是一个由原紫杉烯合成酶催化的反应。我们实现了从蜜环菌菌丝培养物中分离纯化原紫罗兰烯合成酶，发现6-原紫罗兰烯是其唯一的反应产物。因此，需要进一步的异构化反应才能将6-7双键转化为7-8双键。我们在大肠杆菌中表达了一种原紫杉烯合成酶的基因，这也导致了6-原紫罗兰烯的独家生产。分离的倍半萜合成酶的序列比较表明，它与其他真菌萜类合成酶有较远的亲缘关系。基因组序列的分离表明，6-原生紫草烯合成酶以单拷贝基因形式存在于鸡冠花基因组中，具有一个被8个内含子打断的开放阅读框。
Melleolides and related fungal sesquiterpenoid aryl esters are antimicrobial and cytotoxic natural products derived from cultures of the Homobasidiomycetes genus Armillaria. The initial step in the biosynthesis of all melleolides involves cyclization of the universal sesquiterpene precursor farnesyl diphosphate to produce protoilludene, a reaction catalyzed by protoilludene synthase. We achieved the partial purification of protoilludene synthase from a mycelial culture of Armillaria gallica and found that 6-protoilludene was its exclusive reaction product. Therefore, a further isomerization reaction is necessary to convert the 6–7 double bond into the 7–8 double bond found in melleolides. We expressed an A. gallica protoilludene synthase cDNA in Escherichia coli, and this also led to the exclusive production of 6-protoilludene. Sequence comparison of the isolated sesquiterpene synthase revealed a distant relationship to other fungal terpene synthases. The isolation of the genomic sequence identified the 6-protoilludene synthase to be present as a single copy gene in the genome of A. gallica, possessing an open reading frame interrupted with eight introns.