New Insight into the Mechanism of Action of Wasp Mastoparan Peptides: Lytic Activity and Clustering Observed with Giant Vesicles
New Insight into the Mechanism of Action of Wasp Mastoparan Peptides: Lytic Activity and Clustering Observed with Giant Vesicles
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DOI：
10.1021/la202608r
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发表时间：
2011-09-06
期刊：
影响因子：
3.9
通讯作者：
Neto, Joao Ruggiero
中科院分区：
文献类型：
--
作者：
dos Santos Cabrera, Marcia P.;Alvares, Dayane S.;Neto, Joao Ruggiero
乳突抗菌肽家族的抗菌肽通过与脂质膜结合，诱导气孔或缺陷，泄漏囊泡和细胞的内部内容物来发挥其杀菌活性。然而，这似乎并不是唯一的作用机制，它们可能在寻找具有更低不良副作用的改进肽方面很重要。这项工作涉及三种Mastoparan肽，Polybia-MP-1(MP-1), N2-Polybia-MP-1 （N-MP-1）和Mastoparan X (MPX)，它们具有高度的序列同源性。他们都有三个赖氨酸残留物和酰胺化C末端,但因为有两个,一个,,没有天冬氨酸残基,分别为+ 2,+ 3,+ 4净指控生理博士在这里我们关注这些mastoparans肽的影响阴离子组成的细胞膜模型palmitoleyoilphosphatidylcholine (POPC)和palmitoleyoilphosphatidylglycerol (POPG)在1:1和3:1摩尔比率的存在和没有盐水缓冲。Zeta电位实验测量了肽在囊泡表面的结合和积累程度，并获得CD光谱来量化肽结合后的螺旋结构。在相衬和荧光显微镜下观察到巨大的单层囊泡。我们发现，这三种多肽诱导GUVs的泄漏速度是渐进的，并具有许多梯度模式的特征。在没有生理盐水缓冲液的情况下，这个过程更快。此外，我们观察到肽诱导在GUV表面形成磷脂和肽的密集区域。这种现象很容易在带电荷多肽中观察到。（MPX > N-MP-1 > MP-1）和在不添加盐的情况下。我们的数据表明，这些乳突蛋白积聚在双层表面，导致其屏障特性短暂中断，泄漏囊泡内容物。接下来，双分子层恢复其连续性，但这是以一种不均匀的方式发生的，形成一种肽夹在两个并列的膜之间的层。最终，形成肿块的肽脂聚集体在高肽脂比下形成。
Antimicrobial peptides of the mastoparans family exert their bactericidal activity by binding to lipid membranes, inducing pores or defects and leaking the internal contents of vesicles and cells. However, this does not seem to be the only mechanism at play, and they might be important in the search for improved peptides with lower undesirable side effects. This work deals with three mastoparans peptides, Polybia-MP-1(MP-1), N2-Polybia-MP-1 (N-MP-1), and Mastoparan X (MPX), which exhibit high sequence homology. They all have three lysine residues and amidated C termini, but because of the presence of two, one, and no aspartic acid residues, respectively, they have +2, +3, and +4 net charges at physiological pH. Here we focus on the effects of these mastoparans peptides on anionic model membranes made of palmitoleyoilphosphatidylcholine (POPC) and palmitoleyoilphosphatidylglycerol (POPG) at 1:1 and 3:1 molar ratios in the presence and in the absence of saline buffer. Zeta potential experiments were carried out to measure the extent of the peptides' binding and accumulation at the vesicle surface, and CD spectra were acquired to quantify the helical structuring of the peptides upon binding. Giant unilamellar vesicles were observed under phase contrast and fluorescence microscopy. We found that the three peptides induced the leakage of GUVs at a gradual rate with many characteristics of the graded mode. This process was faster in the absence of saline buffer. Additionally, we observed that the peptides induced the formation of dense regions of phospholipids and peptides on the GUV surface. This phenomenon was easily observable for the more charged peptides.(MPX > N-MP-1 > MP-1) and in the absence of added salt. Our data suggest that these mastoparans accumulate on the bilayer surface and induce a transient interruption to its barrier properties, leaking the vesicle contents. Next, the bilayer recovers its continuity, but this happens in an inhomogeneous way, forming a kind of ply with peptides sandwiched between two juxtaposed membranes. Eventually, a peptide-lipid aggregate forming a lump is formed at high peptide-to-lipid ratios.