Leveraging Fungal and Human Calcineurin-Inhibitor Structures, Biophysical Data, and Dynamics To Design Selective and Nonimmunosuppressive FK506 Analogs.
Leveraging Fungal and Human Calcineurin-Inhibitor Structures, Biophysical Data, and Dynamics To Design Selective and Nonimmunosuppressive FK506 Analogs.
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DOI：
10.1128/mbio.03000-21
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发表时间：
2021-12-21
期刊：
影响因子：
6.4
通讯作者：
Spicer LD
中科院分区：
文献类型：
--
作者：
Gobeil SM;Bobay BG;Juvvadi PR;Cole DC;Heitman J;Steinbach WJ;Venters RA;Spicer LD
钙调神经磷酸酶是真菌致病和抗真菌药物耐受的关键酶，因此是一个有吸引力的抗真菌靶点。目前临床上可获得的钙调磷酸酶抑制剂，如FK 506，对人类具有免疫抑制作用，因此利用钙调磷酸酶抑制作为抗真菌策略需要真菌特异性，以避免抑制人类途径。利用真菌钙调神经磷酸酶抑制剂晶体结构，我们最近开发了一种免疫抑制性较低的FK 506类似物APX 879，具有广谱抗真菌活性，在侵袭性真菌感染的小鼠模型中具有明显的疗效。我们的首要目标是在分子水平上更好地了解人类和真菌FK 506结合蛋白（FKBP 12）抑制钙调磷酸酶所需的相互作用决定因素，以指导真菌选择性，非免疫抑制性FK 506类似物的设计。为此，我们表征了与FK 506结合的卷枝毛霉FKBP 12和烟曲霉M.卷须状蛋白和与FK 506类似物APX 879结合的人FKBP 12蛋白，后者对真菌病原体表现出增强的选择性。结合结构，遗传和生物物理方法与分子动力学模拟，我们确定这些结构相似的FKBP 12-配体复合物的关键变化。本文提出的旨在合理设计更有效的钙调磷酸酶抑制剂的工作确实表明，以C15，C16，C18，C36和C37位置为中心的APX 879支架的修饰提供了显着增强真菌选择性的潜力。
Calcineurin is a critical enzyme in fungal pathogenesis and antifungal drug tolerance and, therefore, an attractive antifungal target. Current clinically accessible calcineurin inhibitors, such as FK506, are immunosuppressive to humans, so exploiting calcineurin inhibition as an antifungal strategy necessitates fungal specificity in order to avoid inhibiting the human pathway. Harnessing fungal calcineurin-inhibitor crystal structures, we recently developed a less immunosuppressive FK506 analog, APX879, with broad-spectrum antifungal activity and demonstrable efficacy in a murine model of invasive fungal infection. Our overarching goal is to better understand, at a molecular level, the interaction determinants of the human and fungal FK506-binding proteins (FKBP12) required for calcineurin inhibition in order to guide the design of fungus-selective, nonimmunosuppressive FK506 analogs. To this end, we characterized high-resolution structures of the Mucor circinelloides FKBP12 bound to FK506 and of the Aspergillus fumigatus, M. circinelloides, and human FKBP12 proteins bound to the FK506 analog APX879, which exhibits enhanced selectivity for fungal pathogens. Combining structural, genetic, and biophysical methodologies with molecular dynamics simulations, we identify critical variations in these structurally similar FKBP12-ligand complexes. The work presented here, aimed at the rational design of more effective calcineurin inhibitors, indeed suggests that modifications to the APX879 scaffold centered around the C15, C16, C18, C36, and C37 positions provide the potential to significantly enhance fungal selectivity.