Vitiello Giuseppe, Falanga Annarita, Galdiero Massimiliano, Marsh Derek, Galdiero Stefania, D'Errico Gerardino
Department of Chemistry, University of Naples, Monte Sant'Angelo, Naples, Italy.
Biochim Biophys Acta. 2011 Oct;1808(10):2517-26. doi: 10.1016/j.bbamem.2011.07.012. Epub 2011 Jul 23.
Lipid membranes play a key role in the viral life cycle. Enveloped viruses particularly require a sequence of fusion and fission events between the viral envelope and the target membranes for entry into the cell and egress from it. These processes are controlled by one or more viral glycoproteins that undergo conformational changes favoring the necessary micro- and mesoscopic lipid re-arrangements. Multiple regions from these glycoproteins are thought to interact with the membranes, according to a concerted mechanism, in order to generate the distortion necessary for fusion. In this work, we perform an EPR study on the role played by the membrane composition in tuning the interaction between lipid bilayers and two peptides, gH626-644 and gB632-650, that are highly fusogenic fragments of the gH and gB glycoproteins of herpes simplex virus. Our results show that both peptides interact with lipid bilayers, perturbing the local lipid packing. gH626-644 localizes close to the hydrophilic bilayer surface, while gB632-650 penetrates deeply into the membrane. Chain perturbation by the peptides increases in the presence of charged phospholipids. Finally, cholesterol does not alter the ability of gB632-650 to penetrate deeply in the membrane, whereas it limits penetration of the gH626-644 peptide to the more external layer. The different modes of interaction result in a higher fusogenic ability of gB632-650 towards cholesterol-enriched membranes, as demonstrated by lipid mixing assays. These results suggest that the mechanism of action of the gH and gB glycoproteins is modulated by the properties and composition of the phospholipid bilayer.
脂质膜在病毒生命周期中起着关键作用。包膜病毒尤其需要在病毒包膜与靶膜之间发生一系列融合和裂变事件，以便进入细胞并从中释放出来。这些过程由一种或多种病毒糖蛋白控制，这些糖蛋白会发生构象变化，有利于必要的微观和介观脂质重排。据推测，这些糖蛋白的多个区域会根据协同机制与膜相互作用，以产生融合所需的变形。在这项工作中，我们进行了一项电子顺磁共振（EPR）研究，以探讨膜组成在调节脂质双层与两种肽（gH626 - 644和gB632 - 650）之间相互作用时所起的作用，这两种肽是单纯疱疹病毒gH和gB糖蛋白的高度融合片段。我们的结果表明，这两种肽都与脂质双层相互作用，扰乱了局部脂质堆积。gH626 - 644定位于靠近亲水性双层表面的位置，而gB632 - 650则深入穿透膜。在存在带电磷脂的情况下，肽对链的扰动会增加。最后，胆固醇不会改变gB632 - 650深入穿透膜的能力，而它会将gH626 - 644肽的穿透限制在更外层。脂质混合试验表明，不同的相互作用模式导致gB632 - 650对富含胆固醇的膜具有更高的融合能力。这些结果表明，gH和gB糖蛋白的作用机制受到磷脂双层的性质和组成的调节。
