Two Related Pyrrolidinedione Synthetase Loci in Fusarium heterosporum ATCC 74349 Produce Divergent Metabolites
Two Related Pyrrolidinedione Synthetase Loci in Fusarium heterosporum ATCC 74349 Produce Divergent Metabolites
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DOI：
10.1021/cb400159f
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发表时间：
2013-07-01
影响因子：
4
通讯作者：
Schmidt, Eric W.
中科院分区：
文献类型：
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作者：
Kakule, Thomas B.;Sardar, Debosmita;Schmidt, Eric W.
木贼素合成酶（Equisetin synthetase，EqiS）来源于丝状真菌异孢镰刀菌（Fusarium heterosporum）ATCC 74349，通过基因敲除和表达分析，初步确定了该酶的基因型。实验结果越来越不一致，这使我们对这项任务提出了质疑。在这里，我们测序了F。Heterosporum基因组，揭示了两个杂交聚酮肽蛋白，是木贼素合成酶的候选者。两个簇中的周围基因都有可能负责产生木贼素的所需辅助基因。在真菌中的遗传突变，生化分析和重组表达使我们能够表明，最初分配的EqiS不产生木贼素，而是产生一种相关的24-吡咯烷二酮，fusaridione A，这是以前未知的。镰刀菌二酮A在3-位吡咯烷二酮中甲基化，这在天然产物中没有发现，导致自发的逆-Dieckmann反应。一个新发现的基因簇eqx负责产生木贼素。
Equisetin synthetase (EqiS), from the filamentous fungus Fusarium heterosporum ATCC 74349, was initially assigned on the basis of genetic knockout and expression analysis. Increasing inconsistencies in experimental results led us to question this assignment. Here, we sequenced the F. heterosporum genome, revealing two hybrid polyketide-peptide proteins that were candidates for the equisetin synthetase. The surrounding genes in both clusters had the needed auxiliary genes that might be responsible for producing equisetin. Genetic mutation, biochemical analysis, and recombinant expression in the fungus enabled us to show that the initially assigned EqiS does not produce equisetin but instead produces a related 24-pyrrolidinedione, fusaridione A, that was previously unknown. Fusaridione A is methylated in the 3-position pyrrolidinedione, which has not otherwise been found in natural products, leading to spontaneous reverse-Dieckmann reactions. A newly described gene cluster, eqx, is responsible for producing equisetin.