STRUCTURES OF BOVINE AND HUMAN PAPILLOMAVIRUSES - ANALYSIS BY CRYOELECTRON MICROSCOPY AND 3-DIMENSIONAL IMAGE-RECONSTRUCTION
STRUCTURES OF BOVINE AND HUMAN PAPILLOMAVIRUSES - ANALYSIS BY CRYOELECTRON MICROSCOPY AND 3-DIMENSIONAL IMAGE-RECONSTRUCTION
复制标题
DOI：
10.1016/s0006-3495(91)82181-6
复制
发表时间：
1991-12-01
影响因子：
3.4
通讯作者：
BROWN, JC
中科院分区：
文献类型：
--
作者：
BAKER, TS;NEWCOMB, WW;BROWN, JC
应用冷冻电镜和三维图像重建技术，在2.5nm分辨率下对牛乳头瘤病毒1型（BPV-1）和人乳头瘤病毒1型（HPV-1）的结构进行了研究。正如预期的那样，重建显示两种病毒都由围绕核组蛋白核心的T = 7二十面体衣壳（直径约60 nm）组成。这两种病毒的衣壳形态几乎无法区分。每个衣壳由几乎连续密度的壳层（约2nm厚）组成，壳体从壳层径向突出至约5.8nm的最大高度。五配位（五价）和六配位（六价）壳体都表现出明显的五重轴对称性，如在SV 40和多瘤病毒中观察到的。因此，乳多空病毒科的两个属（乳头瘤和多瘤）现在已经显示具有特征性的“全五聚体”衣壳结构。BPV-1和HPV-1壳粒由一个厚的（直径8.6 nm）主干组成，该主干远端变宽形成规则的五尖星形头部，近端形成壳粒缔合的壳层。圆柱形通道（直径约2.8 nm）从病毒内部沿每个壳粒的轴沿着延伸至壳粒表面约一半处。以减小的半径显示的单个壳体的计算截面图显示，五个壳体亚基（在五价和六价壳体两者中）中的每一个都在衣壳壳的外表面正上方产生明显的（30度）左旋扭转。重建的类似观点也阐明了壳粒间接触的形态。例如，他们展示了六价壳粒如何协调六个相邻的壳粒，尽管它们只含有五个亚基。在BPV-1和HPV-1中，衣壳间接触系统是不可区分的，但与报道的由主要衣壳蛋白VP 1体外组装的多瘤病毒衣壳的系统完全不同（D. M. Salunke，D. L. D. Caspar和R. L.加尔恰1989. Biophys. J. 56：887-900）。因此，由于多瘤病毒和乳头瘤病毒都具有全五聚体衣壳，因此似乎稳定五聚体衣壳的衣壳内亚基-亚基相互作用比那些参与衣壳体-衣壳体接触的相互作用在进化上更好地保留。
The structures of bovine papillomavirus type 1 (BPV-1) and human papillomavirus type 1 (HPV-1) were determined at 2.5 nm resolution by cryoelectron microscopy and three dimensional image reconstruction techniques. As expected, the reconstructions showed that both viruses consist of a T = 7 icosahedral capsid (approximately 60 nm in diameter) which surrounds a nucleohistone core. The capsid morphologies of the two viruses are nearly indistinguishable. Each capsid consists of a shell layer (approximately 2 nm thick) of nearly continuous density from which capsomers project radially to a maximum height of approximately 5.8 nm. The five-coordinate (pentavalent) and six-coordinate (hexavalent) capsomers both exhibit distinct five-fold axial symmetry as was observed for SV40 and polyoma viruses. Thus, both genera (papilloma and polyoma) of the papovavirus family have now been shown to have the characteristic "all-pentamer" capsid construction. BPV-1 and HPV-1 capsomers consist of a thick (8.6 nm diameter) trunk that broadens distally to form a regular five-pointed, star-shaped head, and proximally to create the shell layer where capsomers associate. A cylindrical channel (approximately 2.8 nm diameter) extends along the axis of each capsomer from the interior of the virus to a point approximately half way to the capsomer surface. Computationally sectioned views of individual capsomers displayed at decreasing radii show that each of the five capsomer subunits (in both pentavalent and hexavalent capsomers) makes a pronounced (30-degrees) left-handed twist just above the outer surface of the capsid shell. Similar views of the reconstructions also clarify the morphology of intercapsomer contacts. For example, they show how hexavalent capsomers coordinate six neighboring capsomers despite the fact that they contain only five subunits. The system of intercapsomer contacts is indistinguishable in BPV-1 and HPV-1, but quite different from that reported for polyoma virus capsids assembled in vitro from the major capsid protein, VP1 (D. M. Salunke, D. L. D. Caspar, and R. L. Garcea. 1989. Biophys. J. 56:887-900). Thus, because both polyoma and papilloma viruses have all-pentamer capsids, it appears that intracapsomer subunit-subunit interactions which stabilize pentameric capsomers are better preserved evolutionarily than those involved in capsomer-capsomer contacts.