华中师范大学杨光富团队通过冷冻电镜结构，揭示了甲基四prole在酵母和猪细胞色素bc1复合体中的独特结合模式，实现抑制剂的合理设计。相关研究成果于2024年11月27日发表于国际顶尖学术期刊《美国化学会杂志》。

细胞色素bc1（复合物III）是发现药物和杀菌剂的重要靶标。甲氧基四脯氨酸（MET）通常被归类为醌位点抑制剂（QoI），可以对抗G143A突变分离株，G143A变异分离株对甲氧基丙烯酸酯类杀菌剂如吡唑醚菌酯（PYR）具有高度抗性。MET的结合模式和抗电阻机制尚不清楚。

该文中，研究人员通过冷冻电子显微镜确定了抑制剂结合的酿酒酵母复合物III（MET，2.52；PYR，2.42）和抑制剂结合的猪复合物III。首次观察到MET和PYR的不同结合模式。

值得注意的是，MET在两种物种中表现出不同的结合模式。在酿酒酵母中，MET的结合位点与PYR相同，是Qo位点的Pm型抑制剂。然而，在猪中，MET同时作为Qo和Qi的双靶点抑制剂。基于结构见解，发现了一种新型抑制剂（YF23694），并对霜霉病和白粉病真菌表现出优异的杀菌活性。

该项工作为设计下一代抑制剂以克服耐药性提供了新的起点。

附：英文原文

Title: Cryo-EM Structures Reveal the Unique Binding Modes of Metyltetraprole in Yeast and Porcine Cytochrome bc1 Complex Enabling Rational Design of Inhibitors

Author: Yu-Xia Wang, Ying Ye, Zhi-Wen Li, Guang-Rui Cui, Xing-Xing Shi, Ying Dong, Jia-Jia Jiang, Jia-Yue Sun, Ze-Wei Guan, Nan Zhang, Qiong-You Wu, Fan Wang, Xiao-Lei Zhu, Guang-Fu Yang

Issue&Volume: November 27, 2024

Abstract: Cytochrome bc1 (complex III) represents a significant target for the discovery of both drugs and fungicides. Metyltetraprole (MET) is commonly classified as a quinone site inhibitor (QoI) that combats the G143A mutated isolate, which confers high resistance to strobilurin fungicides such as pyraclostrobin (PYR). The binding mode and antiresistance mechanism of MET remain unclear. Here, we determined the high-resolution structures of inhibitor-bound S. cerevisiae complex III (MET, 2.52 ; PYR, 2.42 ) and inhibitor-bound porcine complex III (MET, 2.53 ; PYR, 2,37 ) by cryo-electron microscopy. The distinct binding modes of MET and PYR were observed for the first time. Notably, the MET exhibited different binding modes in the two species. In S. cerevisiae, the binding site of MET was the same as PYR, serving as a Pm-type inhibitor of the Qo site. However, in porcine, MET acted as a dual-target inhibitor of both Qo and Qi. Based on the structural insights, a novel inhibitor (YF23694) was discovered and demonstrated excellent fungicidal activity against downy mildew and powdery mildew fungi. This work provides a new starting point for the design of the next generation of inhibitors to overcome the resistance.

DOI: 10.1021/jacs.4c12595

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c12595