一株诺西肽产生菌的发掘及发酵条件优化

Discovery of a new nosiheptide-producing strain and its fermentation optimization for nosiheptide production

诺西肽是一种典型的硫肽类抗菌化合物,对多种革兰氏阳性耐药菌具有良好的抗菌活性。尽管水溶性低、体内活性差和结构类似物多等限制了诺西肽的临床应用,但糖基化类似物有望成为解决诺西肽成药难题的方式之一。基于诺西肽的生物合成基因簇信息,利用基因组数据挖掘方法定位了Actinoalloteichus sp.AHMU CJ021菌株,该菌基因组中存在一个由诺西肽合成模块和糖基化模块组成的全新基因簇。但是,在尝试单菌多次级代谢产物策略(OSMAC)和引入调控蛋白NocP等方法后,Actinoalloteichus sp.AHMU CJ021仍无法生物合成糖基化诺西肽,仅能产生结构类似物较少的诺西肽。在此基础上,针对诺西肽的生物合成,采用响应面法优化了Actinoalloteichus sp.AHMU CJ021的发酵条件,使诺西肽合成效价提高了近6倍,达到58.73 mg/L,且极少产生结构类似物。本研究通过基因组挖掘和发酵条件优化,发现了一株适合工业化生产高质量诺西肽的候选菌株,为诺西肽结构类似物的研究提供了基础。

Nosiheptide is a typical thiopeptide antibiotic displaying potent activity toward various drug-resistant strains of Gram-positive pathogens.Although nosiheptide lacks in vivo activity,and good water-solubility with a series of uncontrollable analogues,which may limit its clinical application,glycosylated analogues may overcome problem of low activity and may improve its druggability.In search of novel glycosylated nosiheptide producers,we applied a genome mining strategy that identified Actinoalloteichus sp.AHMU CJ021 that contains all genes required.However,despite the presence of a predicted glycosyltransferase,glycosylated derivatives of nosiheptide were not detected,after following one strain many compounds(OSMAC)strategy and heterologous expression of a regulatory protein NocP.Nevertheless,nosiheptide produced by this strain was remarkably pure,and further experiments were conducted to improve its production by optimization of the culture medium.Under optimal conditions,58.73 mg/L nosiheptide was produced,representing an almost 6-fold improvement compared to the original fermentation medium.Therefore,we consider Actinoalloteichus sp.AHMU CJ021 a suitable potential candidate for industrial production of nosiheptide,which provides the basis for solving the problem of nosiheptide structural analogues.