Engineered biosynthesis of milbemycins in the avermectin high-producing strain Streptomyces avermitilis.
Engineered biosynthesis of milbemycins in the avermectin high-producing strain Streptomyces avermitilis.
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DOI：
10.1186/s12934-017-0626-8
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发表时间：
2017-01-17
影响因子：
6.4
通讯作者：
Yoon YJ
中科院分区：
文献类型：
--
作者：
Kim MS;Cho WJ;Song MC;Park SW;Kim K;Kim E;Lee N;Nam SJ;Oh KH;Yoon YJ
从吸湿链霉菌亚种产生米尔贝菌素。金黄色葡萄球菌和冰城链霉菌是由16个成员组成的大环内酯类化合物，与阿维链霉菌产生的阿维菌素在结构上有相似之处。Milbemycins具有较强的杀螨、杀虫和驱虫活性，但毒性较低。由于米贝霉素的高商业价值和对阿维菌素及其衍生物日益增加的耐药性，开发一种高效的组合生物合成系统，利用高产的宿主菌株来大量生产米贝霉素及其新的类似物势在必行。将阿维菌素高产菌株SA-01中阿维菌素聚酮合成酶(PKS)的AveA1和AveA3(或AveA3中的模块7)分别替换为米尔贝霉素PKS的MilA1和MilA3(或MilA3中的模块7)，导致少量产生米尔贝菌素A3、A4和D及其各自的C5-O甲基化同源米尔贝霉素B2、B3、随后C5-O-甲基转移酶的失活使得商品化产品米贝菌素的主要成分米贝霉素A3/A4在摇瓶和L发酵罐中的产量分别为225 mg/L和377 mg/L，同时还有微量的米贝霉素D。我们证明了米贝霉素的生物合成可以在阿维菌素产生菌中通过组合生物合成进行，其产量水平只有轻微的下降。应用类似的策略，利用高产工业菌株，将提供一个更有效的基于阿维链霉菌的组合生物合成系统，以进一步提高米贝霉素及其新类似物的生产，并提高杀虫潜力。本文的在线版本(doi：10.1186/s12934-0170626-8)包含补充材料，授权用户可以使用。
Milbemycins, produced from Streptomyces hygroscopicus subsp. aureolacrimosus and Streptomyces bingchenggensis, are 16-membered macrolides that share structural similarity with avermectin produced from Streptomyces avermitilis. Milbemycins possess strong acaricidal, insecticidal, and anthelmintic activities but low toxicity. Due to the high commercial value of the milbemycins and increasing resistance to the avermectins and their derivatives, it is imperative to develop an efficient combinatorial biosynthesis system exploiting an overproduction host strain to produce the milbemycins and novel analogs in large quantities. The respective replacement of AveA1 and AveA3 (or module 7 in AveA3) of the avermectin polyketide synthase (PKS) in the avermectin high-producing strain S. avermitilis SA-01 with MilA1 and MilA3 (or module 7 in MilA3) of the milbemycin PKS resulted in the production of milbemycins A3, A4, and D in small amounts and their respective C5-O-methylated congener milbemycins B2, B3, and G as major products with total titers of approximately 292 mg/l. Subsequent inactivation of the C5-O-methyltransferase AveD led to a production of milbemycins A3/A4 (the main components of the commercial product milbemectin) in approximately 225 and 377 mg/l in the flask and 5 l fermenter culture, respectively, along with trace amounts of milbemycin D. We demonstrated that milbemycin biosynthesis can be engineered in the avermectin-producing S. avermitilis by combinatorial biosynthesis with only a slight decrease in its production level. Application of a similar strategy utilizing higher producing industrial strains will provide a more efficient combinatorial biosynthesis system based on S. avermitilis for further enhanced production of the milbemycins and their novel analogs with improved insecticidal potential. The online version of this article (doi:10.1186/s12934-017-0626-8) contains supplementary material, which is available to authorized users.