Identification of novel surfactin derivatives from NRPS modification of Bacillus subtilis and its antifungal activity against Fusarium moniliforme.
Identification of novel surfactin derivatives from NRPS modification of Bacillus subtilis and its antifungal activity against Fusarium moniliforme.
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DOI：
10.1186/s12866-016-0645-3
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发表时间：
2016-03-09
期刊：
影响因子：
4.2
通讯作者：
Zhao H
中科院分区：
文献类型：
--
作者：
Jiang J;Gao L;Bie X;Lu Z;Liu H;Zhang C;Lu F;Zhao H
枯草芽孢杆菌PB2-L1菌株产生脂肽表面素，这是一种由大的多模非核糖体肽合成酶(NRPS)合成的高效生物表面活性剂。在本研究中，利用pKS2介导的同源重组方法，成功地敲除了枯草杆菌BP2-L1中表面蛋白NRPS的模块SrfA-A-Leu、SrfA-B-Asp和SrfA-B-Leu。生产了三种新的表面素产品，分别缺少氨基酸Leu-3、Asp-5或Leu-6。用高效液相色谱和LC-FTICR-MS/MS对这些表面素类进行了检测、分离和表征。与天然表面素相比，[∆Leu3]和[∆Leu6]表面素有明显的减毒作用，而[∆Asp 5]表面素对短小芽孢杆菌和黄色微球菌的抑制作用比天然表面素强。结果表明，[∆Leu6]表面素对串珠镰刀菌的最低抑菌浓度为50μg/mL，可导致菌丝突起、细胞损伤、核酸和蛋白质泄漏。这些因素均可刺激念珠菌的细胞凋亡。结果表明，[∆-Leu6]表面蛋白对念珠菌有显著的抗真菌活性，有望用于控制食品中的真菌污染，提高食品安全性。
Bacillus subtilis strain PB2-L1 produces the lipopeptide surfactin, a highly potent biosurfactant synthesized by a large multimodular nonribosomal peptide synthetase (NRPS). In the present study, the modules SrfA-A-Leu, SrfA-B-Asp, and SrfA-B-Leu from surfactin NRPS in B. subtilis BP2-L1 were successfully knocked-out using a temperature-sensitive plasmid, pKS2-mediated-based, homologous, recombination method. Three novel surfactin products were produced, individually lacking amino acid Leu-3, Asp-5, or Leu-6. These surfactins were detected, isolated, and characterized by HPLC and LC-FTICR-MS/MS. In comparison with native surfactin, [∆Leu3]surfactin and [∆Leu6]surfactin showed evidence of reduced toxicity, while [∆Asp5]surfactin showed stronger inhibition than native surfactin against B. pumilus and Micrococcus luteus. These results showed that the minimum inhibitory concentration of [∆Leu6]surfactin for Fusarium moniliforme was 50 μg/mL, such that [∆Leu6]surfactin could lead to mycelium projection, cell damage, and leakage of nucleic acids and protein. These factors all contributed to stimulating apoptosis in F. moniliforme. The present results revealed that [∆Leu6]surfactin showed a significant antifungal activity against F. moniliforme and might successfully be employed to control fungal food contamination and improve food safety.