Zuber G, Barklis E
Vollum Institute, Department of Microbiology, Oregon Health Sciences University, Portland, Oregon 97201-3098 USA.
Biophys J. 2000 Jan;78(1):373-84. doi: 10.1016/S0006-3495(00)76600-8.
We have used an in vitro system that mimics the assembly of immature Moloney murine leukemia virus (M-MuLV) particles to examine how viral structural (Gag) proteins oligomerize at membrane interfaces. Ordered arrays of histidine-tagged Moloney capsid protein (his-MoCA) were obtained on membrane bilayers composed of phosphatidylcholine (PC) and the nickel-chelating lipid 1, 2-di-O-hexadecyl-sn-glycero-3-(1'-2"-R-hydroxy-3'N-(5-amino-1-carboxy pentyl)iminodiacetic acid)propyl ether (DHGN). The membrane-bound arrays were analyzed by electron microscopy (EM) and atomic force microscopy (AFM). Two-dimensional projection images obtained by EM showed that bilayer-bound his-MoCA proteins formed cages surrounding different types of protein-free cage holes with similar cage holes spaced at 81.5-A distances and distances between dissimilar cage holes of 45.5 A. AFM images, showing topological features viewed near the membrane-proximal domain of the his-MoCA protein, revealed a cage network of only symmetrical hexamers spaced at 79-A distances. These results are consistent with a model in which dimers constitute structural building blocks and where membrane-proximal and distal his-MoCA regions interact with different partners in membrane-bound arrays.
我们使用了一种体外系统，该系统模拟未成熟莫洛尼鼠白血病病毒（M-MuLV）颗粒的组装过程，以研究病毒结构（Gag）蛋白如何在膜界面处寡聚化。在由磷脂酰胆碱（PC）和镍螯合脂质1,2-二-O-十六烷基-sn-甘油-3-(1'-2"-R-羟基-3'N-(5-氨基-1-羧基戊基)亚氨基二乙酸)丙基醚（DHGN）组成的膜双层上获得了组氨酸标记的莫洛尼衣壳蛋白（his-MoCA）的有序阵列。通过电子显微镜（EM）和原子力显微镜（AFM）对膜结合阵列进行了分析。EM获得的二维投影图像显示，双层结合的his-MoCA蛋白形成了围绕不同类型无蛋白笼孔的笼子，类似的笼孔间距为81.5埃，不同笼孔之间的距离为45.5埃。AFM图像显示了在his-MoCA蛋白膜近端区域附近观察到的拓扑特征，揭示了一个仅由间距为79埃的对称六聚体组成的笼状网络。这些结果与一个模型一致，在该模型中，二聚体构成结构构建块，并且膜近端和远端的his-MoCA区域在膜结合阵列中与不同的伙伴相互作用。
