Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China.
School of Medicine, Linyi University, Shuangling Road, Linyi 276000, China.
Molecules. 2023 Oct 5;28(19):6937. doi: 10.3390/molecules28196937.
Glutarimide-containing polyketides exhibiting potent antitumor and antimicrobial activities were encoded via conserved module blocks in various strains that favor the genomic mining of these family compounds. The bioinformatic analysis of the genome of ATCC 10248 showed a silent -AT PKS biosynthetic gene cluster (BGC) on chromosome 2 (Chr2C8), which was predicted to produce new glutarimide-containing derivatives. Then, the silent polyketide synthase gene cluster was successfully activated via in situ promoter insertion and heterologous expression. As a result, seven glutarimide-containing analogs, including five new ones, gladiofungins D-H (-), and two known gladiofungin A/gladiostatin () and (named gladiofungin C), were isolated from the fermentation of the activated mutant. Their structures were elucidated through the analysis of HR-ESI-MS and NMR spectroscopy. The structural diversities of gladiofungins may be due to the degradation of the butenolide group in gladiofungin A () during the fermentation and extraction process. Bioactivity screening showed that and had moderate anti-inflammatory activities. Thus, genome mining combined with promoter engineering and heterologous expression were proved to be effective strategies for the pathway-specific activation of the silent BGCs for the directional discovery of new natural products.
含有戊二酰亚胺的聚酮类化合物具有很强的抗肿瘤和抗菌活性，它们的编码是通过在有利于这些家族化合物基因组挖掘的各种菌株中的保守模块块进行的。对 ATCC 10248 基因组的生物信息学分析表明，在染色体 2（Chr2C8）上存在一个沉默的 -AT PKS 生物合成基因簇（BGC），该基因簇预计会产生新的含有戊二酰亚胺的衍生物。然后，通过原位启动子插入和异源表达成功激活了沉默的聚酮合酶基因簇。结果，从激活突变体的发酵中分离出了七种含有戊二酰亚胺的类似物，包括五种新的 gladiofungin D-H（-），以及两种已知的 gladiostatin（）和（命名为 gladiogunin C）。通过 HR-ESI-MS 和 NMR 光谱分析确定了它们的结构。Gladiofungins 的结构多样性可能是由于在发酵和提取过程中 gladiofungin A（）中环丁烯内酯基团的降解所致。生物活性筛选表明，和具有中等抗炎活性。因此，基因组挖掘结合启动子工程和异源表达被证明是沉默 BGCs 途径特异性激活的有效策略，可定向发现新的天然产物。
