Epoxomicin and Eponemycin Biosynthesis Involves gem‐Dimethylation and an Acyl‐CoA Dehydrogenase‐Like Enzyme
Epoxomicin and Eponemycin Biosynthesis Involves gem‐Dimethylation and an Acyl‐CoA Dehydrogenase‐Like Enzyme
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DOI：
10.1002/cbic.201500567
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发表时间：
2016-05
期刊：
影响因子：
3.2
通讯作者：
J. Zettler;Florian Zubeil;A. Kulik;S. Grond;Leonard Kaysser
中科院分区：
文献类型：
--
作者：
J. Zettler;Florian Zubeil;A. Kulik;S. Grond;Leonard Kaysser
蛋白酶体抑制剂的α′，β′-环氧酮部分赋予催化蛋白酶体β亚基中N-末端苏氨酸高结合特异性。我们最近确定了环氧霉素和eponemycin生物合成基因簇，现在已经进行了同位素富集前体喂养研究和全面的基因缺失实验，以进一步阐明其生物合成途径。亮氨酸和来自S-腺苷甲硫氨酸的两个甲基容易地掺入环氧酮弹头中，表明硫酯中间体脱羧。α′，β′-环氧酮的形成可能是由保守的酰基辅酶A脱氢酶样酶介导的，如在相应的敲除突变体中完全丧失环氧霉素和eponemycin生产所示。我们的研究结果澄清了环氧酮化合物形成中的关键问题，并为这类重要的蛋白酶体抑制剂的生物合成的体外生物化学研究奠定了基础。
The α′,β′‐epoxyketone moiety of proteasome inhibitors confers high binding specificity to the N‐terminal threonine in catalytic proteasome β‐subunits. We recently identified the epoxomicin and eponemycin biosynthetic gene clusters and have now conducted isotope‐enriched precursor feeding studies and comprehensive gene deletion experiments to shed further light on their biosynthetic pathways. Leucine and two methyl groups from S‐adenosylmethionine were readily incorporated into the epoxyketone warhead, suggesting decarboxylation of the thioester intermediate. Formation of the α′,β′‐epoxyketone is likely mediated by conserved acyl‐CoA dehydrogenase‐like enzymes, as indicated by complete loss of epoxomicin and eponemycin production in the respective knockout mutants. Our results clarify crucial questions in the formation of epoxyketone compounds and lay the foundation for in vitro biochemical studies on the biosynthesis of this pharmaceutically important class of proteasome inhibitors.