Liu Huiming, Fan Zhiying, Tong Nian, Lin Jing, Huang Yong, Duan Yanwen, Zhu Xiangcheng
Xiangya International Academy of Translational Medicine, Central South University, Tongzipo Road, #172, Yuelu District, Changsha, Hunan, 410013, China.
National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, Changsha, Hunan, 410013, China.
Microb Cell Fact. 2024 Dec 19;23(1):337. doi: 10.1186/s12934-024-02613-9.
Universal stress proteins (USPs) are prevalent in various bacteria to cope with different adverse stresses, while their possible effects on secondary metabolisms of hosts are unclear. Tiancimycins (TNMs) are ten-membered endiynes possessing excellent potential for development of anticancer antibody-drug conjugates. During our efforts to improve TNMs titer, a high-producing strain Streptomyces sp. CB03234-S had been obtained and its possible high yield mechanism is being continuously explored to further enhance TNMs production.
In this work, the whole-genome resequencing and analysis results revealed a notable 583 kb terminal deletion containing 8 highly expressed usp genes in the genome of CB03234-S. The individual complementation of lost USPs in CB03234-S all showed differential effects on secondary metabolism, especially TNMs production. Among them, the overexpression of USP3 increased TNMs titer from 12.8 ± 0.2 to 31.1 ± 2.3 mg/L, while the overexpression of USP8 significantly reduced TNMs titer to only 1.0 ± 0.1 mg/L, but activated the production of porphyrin-type compounds. Subsequent genetic manipulations on USP3/USP8 orthologs in Streptomyces. coelicolor A3(2) and Streptomyces sp. CB00271 also presented clear effects on the secondary metabolisms of hosts. Further sequence similarity network analysis and Streptomyces-based pan‑genomic analysis suggested that the USP3/USP8 orthologs are widely distributed across Streptomyces.
Our studies shed light on the potential effects of USPs on secondary metabolisms of streptomycetes for the first time, and USPs could become novel targets for exploring and exploiting natural products in streptomycetes.
通用应激蛋白（USPs）在各种细菌中普遍存在，以应对不同的不利应激，但其对宿主次级代谢的可能影响尚不清楚。天蚕霉素（TNMs）是具有十个成员的烯二炔类化合物，在抗癌抗体药物偶联物的开发方面具有优异的潜力。在我们提高TNMs产量的过程中，获得了一株高产菌株链霉菌属CB03234-S，并不断探索其可能的高产机制以进一步提高TNMs产量。
在这项工作中，全基因组重测序和分析结果显示，CB03234-S基因组中存在一个显著的583 kb末端缺失，其中包含8个高表达的usp基因。在CB03234-S中对缺失的USPs进行单独互补，均对次级代谢产生了不同的影响，尤其是对TNMs的产量。其中，USP3的过表达使TNMs产量从12.8±0.2 mg/L提高到31.1±2.3 mg/L，而USP8的过表达则使TNMs产量显著降低至仅1.0±0.1 mg/L，但激活了卟啉类化合物的产生。随后对天蓝色链霉菌A3(2)和链霉菌属CB00271中的USP3/USP8直系同源物进行基因操作，也对宿主的次级代谢产生了明显影响。进一步的序列相似性网络分析和基于链霉菌的泛基因组分析表明，USP3/USP8直系同源物广泛分布于链霉菌中。
我们的研究首次揭示了USPs对链霉菌次级代谢的潜在影响，并且USPs可能成为探索和开发链霉菌中天然产物的新靶点。
