Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
Int J Mol Sci. 2018 Jan 10;19(1):211. doi: 10.3390/ijms19010211.
A minimal model system for membrane fusion, comprising two complementary peptides dubbed "E" and "K" joined to a cholesterol anchor via a polyethyleneglycol spacer, has previously been developed in our group. This system promotes the fusion of large unilamellar vesicles and facilitates liposome-cell fusion both in vitro and in vivo. Whilst several aspects of the system have previously been investigated to provide an insight as to how fusion is facilitated, anchor positioning has not yet been considered. In this study, the effects of placing the anchor at either the N-terminus or in the center of the peptide are investigated using a combination of circular dichroism spectroscopy, dynamic light scattering, and fluorescence assays. It was discovered that anchoring the "K" peptide in the center of the sequence had no effect on its structure, its ability to interact with membranes, or its ability to promote fusion, whereas anchoring the 'E' peptide in the middle of the sequence dramatically decreases fusion efficiency. We postulate that anchoring the 'E' peptide in the middle of the sequence disrupts its ability to form homodimers with peptides on the same membrane, leading to aggregation and content leakage.
我们小组先前开发了一种用于膜融合的最小模型系统，由两个互补的肽“E”和“K”组成，通过聚乙二醇间隔臂连接到胆固醇锚上。该系统可促进大单层囊泡融合，并促进体外和体内脂质体与细胞融合。虽然已经对该系统的几个方面进行了研究，以深入了解融合是如何促进的，但锚定位置尚未得到考虑。在这项研究中，使用圆二色性光谱、动态光散射和荧光分析相结合的方法，研究了将锚定在肽的 N 端或中心对肽的影响。研究发现，将“K”肽锚定在序列的中心对其结构、与膜相互作用的能力或促进融合的能力没有影响，而将“E”肽锚定在序列的中间则大大降低了融合效率。我们推测，将“E”肽锚定在序列的中间会破坏其与同一膜上的肽形成同源二聚体的能力，导致聚集和内容物泄漏。
