Wu Yihan, Seyedsayamdost Mohammad R
Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States.
Department of Molecular Biology , Princeton University , Princeton , New Jersey 08544 , United States.
Biochemistry. 2018 Jul 24;57(29):4247-4251. doi: 10.1021/acs.biochem.8b00678. Epub 2018 Jul 12.
Burkholderia thailandensis produces an impressive array of secondary metabolites, most with yet unknown targets. One of these metabolites is thailandamide, a linear polyene natural product that is constitutively synthesized by the corresponding tha gene cluster. Using broad bioactivity screens, we observed strong yet selective antibacterial activity by thailandamide against Gram-positive and cell wall-weakened Gram-negative bacteria. Bacterial cytological profiling and comparison with 10 antibiotics with known modes of action revealed a unique profile for thailandamide, suggesting a distinct mechanism of inhibition. To address the target of the drug, we obtained resistant mutants of Bacillus subtilis and mapped the resistant phenotype to accA, the product of which catalyzes the first committed step in fatty acid biosynthesis. Interestingly, the tha gene cluster encodes an accA homologue with a similar amino acid substitution. Heterologous expression showed that it confers resistance to otherwise susceptible Escherichia coli cultures, indicating that it provides immunity to thailandamide-producing B. thailandensis cells. Aside from moiramide B and andrimid, thailandamide represents only the second class of natural products that inhibits bacterial growth by targeting AccA/AccD.
泰国伯克霍尔德氏菌能产生一系列令人印象深刻的次级代谢产物，其中大多数的作用靶点尚不清楚。这些代谢产物之一是泰国酰胺，一种线性多烯天然产物，由相应的tha基因簇组成型合成。通过广泛的生物活性筛选，我们观察到泰国酰胺对革兰氏阳性菌和细胞壁弱化的革兰氏阴性菌具有强大且具有选择性的抗菌活性。细菌细胞学分析以及与10种已知作用模式的抗生素进行比较，揭示了泰国酰胺独特的作用模式，表明其具有独特的抑制机制。为了确定该药物的作用靶点，我们获得了枯草芽孢杆菌的抗性突变体，并将抗性表型定位到accA，其产物催化脂肪酸生物合成的第一步关键反应。有趣的是，tha基因簇编码一个具有相似氨基酸取代的accA同源物。异源表达表明，它赋予原本敏感的大肠杆菌培养物抗性，这表明它为产生泰国酰胺的泰国伯克霍尔德氏菌细胞提供了免疫保护。除了莫伊拉酰胺B和安迪米德外，泰国酰胺是仅有的第二类通过靶向AccA/AccD抑制细菌生长的天然产物。
