Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California, San Diego, School of Medicine, La Jolla, California, USA.
Department of Synthetic Biology and Bioenergy, J. Craig Venter Institute, La Jolla, California, USA.
Sci Rep. 2016 Jun 13;6:27806. doi: 10.1038/srep27806.
The spiroindolones, a new class of antimalarial medicines discovered in a cellular screen, are rendered less active by mutations in a parasite P-type ATPase, PfATP4. We show here that S. cerevisiae also acquires mutations in a gene encoding a P-type ATPase (ScPMA1) after exposure to spiroindolones and that these mutations are sufficient for resistance. KAE609 resistance mutations in ScPMA1 do not confer resistance to unrelated antimicrobials, but do confer cross sensitivity to the alkyl-lysophospholipid edelfosine, which is known to displace ScPma1p from the plasma membrane. Using an in vitro cell-free assay, we demonstrate that KAE609 directly inhibits ScPma1p ATPase activity. KAE609 also increases cytoplasmic hydrogen ion concentrations in yeast cells. Computer docking into a ScPma1p homology model identifies a binding mode that supports genetic resistance determinants and in vitro experimental structure-activity relationships in both P. falciparum and S. cerevisiae. This model also suggests a shared binding site with the dihydroisoquinolones antimalarials. Our data support a model in which KAE609 exerts its antimalarial activity by directly interfering with P-type ATPase activity.
螺环吲哚酮类是一类在细胞筛选中发现的新型抗疟药物，其活性因寄生虫 P 型 ATP 酶 PfATP4 的突变而降低。我们在这里表明，暴露于螺环吲哚酮后，酿酒酵母也会在编码 P 型 ATP 酶（ScPMA1）的基因中获得突变，这些突变足以引起耐药性。ScPMA1 中的 KAE609 耐药突变不会赋予对其他无关抗生素的耐药性，但对烷基-溶血磷脂酰乙醇胺（edelfosine）具有交叉敏感性，已知该药物可将 ScPma1p 从质膜上置换下来。我们使用体外无细胞测定法证明，KAE609 可直接抑制 ScPma1p ATP 酶活性。KAE609 还会增加酵母细胞中的细胞质氢离子浓度。计算机对接入 ScPma1p 同源模型确定了一种结合模式，该模式支持寄生虫 falciparum 和酿酒酵母中的遗传耐药决定因素和体外实验结构-活性关系。该模型还表明与二氢异喹啉类抗疟药具有共同的结合位点。我们的数据支持这样一种模型，即 KAE609 通过直接干扰 P 型 ATP 酶活性来发挥其抗疟活性。
