The host-defense peptide piscidin P1 reorganizes lipid domains in membranes and decreases activation energies in mechanosensitive ion channels
The host-defense peptide piscidin P1 reorganizes lipid domains in membranes and decreases activation energies in mechanosensitive ion channels
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DOI：
10.1074/jbc.ra119.010232
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发表时间：
2019-12-06
影响因子：
4.8
通讯作者：
Mihailescu, Ella
中科院分区：
文献类型：
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作者：
Comert, Fatih;Greenwood, Alexander;Mihailescu, Ella
宿主防御肽 (HDP) piscidin 1 (P1) 是从条纹鲈的肥大细胞中分离出来的，具有对抗细菌、病毒、真菌和癌细胞的有效活性，还可以调节膜受体的活性。鉴于其广泛的药理学潜力，我们在这里使用了几种方法来更好地了解其与代表细菌（磷脂酰乙醇胺（PE）/磷脂酰甘油）和哺乳动物（磷脂酰胆碱/胆固醇（PC/Chol））膜模型的多组分双层的相互作用。使用固态 NMR，我们解析了与 PC/Chol 结合的 P1 的结构，并将其与 P3（一种效力较低的同系物）的结构进行了比较。比较表明，尽管两种肽都是界面结合且呈β螺旋，但它们的双层方向和插入深度不同，并且这些差异取决于双层组成。虽然 Chol 被认为可以使哺乳动物细胞膜不易受到 HDP 介导的不稳定的影响，但我们发现 Chol 不会影响 P1 的透化作用。 X 射线衍射实验表明，两种鱼素通过增加 Chol 耗尽相的比例，在 PC/Chol 膜中产生分层效应。此外，P1 提高了 PE 双层中层状相变至六方相变所需的温度，表明它施加了正膜曲率。对大肠杆菌内膜的膜片钳测量表明，P1 和 P3 在足以发挥抗菌活性的浓度下，可显着降低细菌机械敏感通道的激活张力。这表明piscidins可以引起蛋白质附近微环境中的脂质重新分布和重组。我们得出的结论是，piscidin 的抗菌活性机制超出了简单的膜不稳定作用，有助于合理化其更广泛的药理作用。
The host-defense peptide (HDP) piscidin 1 (P1), isolated from the mast cells of striped bass, has potent activities against bacteria, viruses, fungi, and cancer cells and can also modulate the activity of membrane receptors. Given its broad pharmacological potential, here we used several approaches to better understand its interactions with multicomponent bilayers representing models of bacterial (phosphatidylethanolamine (PE)/phosphatidylglycerol) and mammalian (phosphatidylcholine/cholesterol (PC/Chol)) membranes. Using solid-state NMR, we solved the structure of P1 bound to PC/Chol and compared it with that of P3, a less potent homolog. The comparison disclosed that although both peptides are interfacially bound and ?-helical, they differ in bilayer orientations and depths of insertion, and these differences depend on bilayer composition. Although Chol is thought to make mammalian membranes less susceptible to HDP-mediated destabilization, we found that Chol does not affect the permeabilization effects of P1. X-ray diffraction experiments revealed that both piscidins produce a demixing effect in PC/Chol membranes by increasing the fraction of the Chol-depleted phase. Furthermore, P1 increased the temperature required for the lamellar?to?hexagonal phase transition in PE bilayers, suggesting that it imposes positive membrane curvature. Patch-clamp measurements on the inner Escherichia coli membrane showed that P1 and P3, at concentrations sufficient for antimicrobial activity, substantially decrease the activating tension for bacterial mechanosensitive channels. This indicated that piscidins can cause lipid redistribution and restructuring in the microenvironment near proteins. We conclude that the mechanism of piscidin's antimicrobial activity extends beyond simple membrane destabilization, helping to rationalize its broader spectrum of pharmacological effects.