Discovery and Characterization of a Group of Fungal Polycyclic Polyketide Prenyltransferases
Discovery and Characterization of a Group of Fungal Polycyclic Polyketide Prenyltransferases
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DOI：
10.1021/ja3028636
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发表时间：
2012-06-06
影响因子：
15
通讯作者：
Tang, Yi
中科院分区：
文献类型：
--
作者：
Chooi, Yit-Heng;Wang, Peng;Tang, Yi
异丙烯基转移酶(PTase)基因VRTC被认为与青霉毒素(1)的生物合成有关。靶向基因缺失和体外重组VRTC活性的重建证实了VRTC是一种香叶基转移酶，它催化6碳上的环二酮甲酰胺中间体2与香叶基二磷酸发生区域特异性的Friedel-Craft烷基化反应。VRTC可以在没有二价离子的情况下发挥作用，并且可以利用类似的环二酮底物，例如乙酰基引发的TAN-1612(4)。使用VRTC蛋白序列的基因组挖掘导致在人类和动物相关真菌的基因组中鉴定出一组同源的PTase基因。这个新的PTase基因亚群编码的三种酶在体外能够催化二甲基烯丙基转移到几种四环的环二酮底物上。总共生成了7个C-5-或C-10-戊烯基环二酮化合物。这些新的多环PTase(PcPTase)的区域选择性通过对4在大肠杆菌中生物转化得到的产物9的鉴定得到了证实。这个新的PTase亚群的发现扩展了我们用于修饰多环化合物的酶工具，并使新的预烯基化聚酮的基因组挖掘成为可能。
The prenyltransferase (PTase) gene vrtC was proposed to be involved in viridicatumtoxin (1) biosynthesis in Penicillium aethiopicum. Targeted gene deletion and reconstitution of recombinant VrtC activity in vitro established that VrtC is a geranyl transferase that catalyzes a regiospecific Friedel-Crafts alkylation of the naphthacenedione carboxamide intermediate 2 at carbon 6 with geranyl diphosphate. VrtC can function in the absence of divalent ions and can utilize similar naphthacenedione substrates, such as the acetyl-primed TAN-1612 (4). Genome mining using the VrtC protein sequence leads to the identification of a homologous group of PTase genes in the genomes of human and animal-associated fungi. Three enzymes encoded by this new subgroup of PTase genes from Neosartorya fischeri, Microsporum can is, and Trichophyton tonsurans were shown to be able to catalyze transfer of dimethylallyl to several tetracyclic naphthacenedione substrates in vitro. In total, seven C-5- or C-10-prenylated naphthacenedione compounds were generated. The regioselectivity of these new polycyclic PTases (pcPTases) was confirmed by characterization of product 9 obtained from biotransformation of 4 in Escherichia coli expressing the N. fischeri pcPTase gene. The discovery of this new subgroup of PTases extends our enzymatic tools for modifying polycyclic compounds and enables genome mining of new prenylated polyketides.