Improvement of Rimocidin Biosynthesis by Increasing Supply of Precursor Malonyl-CoA via Over-expression of Acetyl-CoA Carboxylase in Streptomyces rimosus M527
Improvement of Rimocidin Biosynthesis by Increasing Supply of Precursor Malonyl-CoA via Over-expression of Acetyl-CoA Carboxylase in Streptomyces rimosus M527
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DOI：
10.1007/s00284-022-02867-9
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发表时间：
2022-06-01
影响因子：
2.6
通讯作者：
Yu, Xiaoping
中科院分区：
文献类型：
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作者：
Liao, Zhijun;Zhang, Jinyao;Yu, Xiaoping
前体工程是解决次生代谢产物过剩的有效策略。多烯大环内酯环霉素是由链霉菌（Streptomyces rimosus M527）产生的，对多种植物病原真菌具有很强的活性。预测丙二酰辅酶a可作为环霉素生物合成的扩展单元。通过对三组不同发酵条件下的S. rimosus M527时间序列转录组芯片数据的系统分析，发现了编码乙酰辅酶a羧化酶（acc）的差异表达基因acc（sr）。为了了解acc（sr）基因的表达和丙二酰辅酶a的浓度如何影响环莫西丁的形成，本研究克隆了acc（sr）基因并在野生型菌株S. rimosus M527中过表达。在整个发酵过程中，含有过表达acc（sr）基因的重组菌株S. rimosus M527- acc在acc酶活性、细胞内丙二酰辅酶a浓度和环霉素产量方面表现优于S. rimosus M527。与S. rimosus M527相比，S. rimosus M527的ACC酶活性和细胞内丙二酰辅酶a浓度分别高出1.0倍和1.5倍。菌株M527- acc产环莫西丁的产率达到320.7 mg/L，比菌株M527的产率提高34.0%。这些结果证实丙二酰辅酶a是环莫西丁生物合成的重要前体，并提示acc（sr）基因过表达导致丙二酰辅酶a的充足供应导致环莫西丁产量的提高。
Precursor engineering is an effective strategy for the overproduction of secondary metabolites. The polyene macrolide rimocidin, which is produced by Streptomyces rimosus M527, exhibits a potent activity against a broad range of phytopathogenic fungi. It has been predicted that malonyl-CoA is used as extender units for rimocidin biosynthesis. Based on a systematic analysis of three sets of time-series transcriptome microarray data of S. rimosus M527 fermented in different conditions, the differentially expressed acc(sr) gene that encodes acetyl-CoA carboxylase (ACC) was found. To understand how the formation of rimocidin is being influenced by the expression of the acc(sr) gene and by the concentration of malonyl-CoA, the acc(sr) gene was cloned and over-expressed in the wild-type strain S. rimosus M527 in this study. The recombinant strain S. rimosus M527-ACC harboring the over-expressed acc(sr) gene exhibited better performances based on the enzymatic activity of ACC, intracellular malonyl-CoA concentrations, and rimocidin production compared to S. rimosus M527 throughout the fermentation process. The enzymatic activity of ACC and intracellular concentration of malonyl-CoA of S. rimosus M527-ACC were 1.0- and 1.5-fold higher than those of S. rimosus M527, respectively. Finally, the yield of rimocidin produced by S. rimosus M527-ACC reached 320.7 mg/L, which was 34.0% higher than that of S. rimosus M527. These results confirmed that malonyl-CoA is an important precursor for rimocidin biosynthesis and suggested that an adequate supply of malonyl-CoA caused by acc(sr) gene over-expression led to the improvement in rimocidin production.