The biosynthetic pathway for aurofusarin in Fusarium graminearum reveals a close link between the naphthoquinones and naphthopyrones
The biosynthetic pathway for aurofusarin in Fusarium graminearum reveals a close link between the naphthoquinones and naphthopyrones
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DOI：
10.1111/j.1365-2958.2006.05295.x
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发表时间：
2006-08-01
影响因子：
3.6
通讯作者：
Giese, Henriette
中科院分区：
文献类型：
--
作者：
Frandsen, Rasmus J. N.;Nielsen, Nikoline J.;Giese, Henriette
真菌聚酮生物合成通常涉及多个酶促步骤，并且编码基因通常以基因簇的形式存在。一个基因簇PKS12，聚酮合酶基因负责合成的色素金镰孢菌素，基因置换使用根癌农杆菌介导的转化，以确定金镰孢菌素的生物合成途径进行了分析。用hygB替换aurR1表明，它编码一种正作用转录因子，该因子是属于该基因簇的PKS12、aurJ、aurF、gip 1和FG02329.1的完全表达所需的。AurR1和PKS12缺失突变体不能产生金镰菌素和红镰菌素。生物信息学和化学信息学结合置换突变体（Delta aur J、Delta aur F、Delta gip 1、Delta aur O和Delta PKS 12）的化学分析表明，以红镰菌素为中间体的金镰菌素生物合成的酶催化途径为五步。这将萘并吡喃酮和萘醌的生物合成联系在一起。假定的转录因子aurR2的替换导致红镰菌素相对于金镰菌素的水平增加。Gip1是一种推定的漆酶，被认为是负责两个氧化红镰孢菌素分子的二聚化，从而形成金镰孢菌素。
Fungal polyketide biosynthesis typically involves multiple enzymatic steps and the encoding genes are often found in gene clusters. A gene cluster containing PKS12, the polyketide synthase gene responsible for the synthesis of the pigment aurofusarin, was analysed by gene replacement using Agrobacterium tumefaciens-mediated transformation to determine the biosynthesis pathway of aurofusarin. Replacement of aurR1 with hygB shows that it encodes a positively acting transcription factor that is required for the full expression of PKS12, aurJ, aurF, gip1 and FG02329.1, which belong to the gene cluster. AurR1 and PKS12 deletion mutants are unable to produce aurofusarin and rubrofusarin. Bio- and chemoinformatics combined with chemical analysis of replacement mutants (Delta aurJ, Delta aurF, Delta gip1, Delta aurO and Delta PKS12) indicate a five-step enzyme catalysed pathway for the biosynthesis of aurofusarin, with rubrofusarin as an intermediate. This links the biosynthesis of naphthopyrones and naphthoquinones together. Replacement of the putative transcription factor aurR2 results in an increased level of rubrofusarin relative to aurofusarin. Gip1, a putative laccase, is proposed to be responsible for the dimerization of two oxidized rubrofusarin molecules resulting in the formation of aurofusarin.