Atomic force microscopy differentiates discrete size distributions between membrane protein containing and empty nanolipoprotein particles
Atomic force microscopy differentiates discrete size distributions between membrane protein containing and empty nanolipoprotein particles
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DOI：
10.1016/j.bbamem.2008.11.019
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发表时间：
2009-03-01
影响因子：
3.4
通讯作者：
Sulchek, Todd A.
中科院分区：
文献类型：
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作者：
Blanchette, Craig D.;Cappuccio, Jenny A.;Sulchek, Todd A.
为了更好地了解膜蛋白进入盘状纳米脂蛋白颗粒(NLP)的过程，我们使用原子力显微镜(AFM)对在细菌视紫红质(BR)、脂蛋白E4 N末端22K片段支架和DMPC脂存在下组装的NLP进行了成像和分析。自组装过程产生了两个不同的NLP群体：含有插入BR的NLP群体(BR-NLP)和不含BR的NLP群体(空NLP)。通过AFM测量，BR-NLP与空NLP的高度平均增加了1.0 nm。链霉亲和素与生物素化BR的结合证实了最初的1.0 nm高度增加对应于br-NLP的掺入。原子力显微镜和离子迁移率谱(IMS)测量表明，NLP大小并不在单个平均值附近变化，而是有几个由离散直径分开的亚群。有趣的是，当BR存在于组装过程中时，直径分布向较大的颗粒移动，且较大的颗粒比较小的颗粒更有可能含有BR，这表明膜蛋白改变了NLP组装的机制。(C)2008爱思唯尔B.V.保留所有权利。
To better understand the incorporation of membrane proteins into discoidal nanolipoprotein particles (NLPs) we have used atomic force microscopy (AFM) to image and analyze NLPs assembled in the presence of bacteriorhodopsin (bR), lipoprotein E4 n-terminal 22k fragment scaffold and DMPC lipid. The self-assembly process produced two distinct NLP populations: those containing inserted bR(bR-NLPs) and those that did not (empty-NLPs). The bR-NLPs were distinguishable from empty-NLPs by an average increase in height of 1.0 nm as measured by AFM. Streptavidin binding to biotinylated bR confirmed that the original 1.0 nm height increase corresponds to br-NLP incorporation. AFM and ion mobility spectrometry (IMS) measurements suggest that NLP size did not vary around a single mean but instead there were several subpopulations, which were separated by discrete diameters. Interestingly, when bR was present during assembly the diameter distribution was shifted to larger particles and the larger particles had a greater likelihood of containing bR than smaller particles, suggesting that membrane proteins alter the mechanism of NLP assembly. (C) 2008 Elsevier B.V. All rights reserved.