The VP2/VP3 minor capsid protein of simian virus 40 promotes the in vitro assembly of the major capsid protein VP1 into particles
The VP2/VP3 minor capsid protein of simian virus 40 promotes the in vitro assembly of the major capsid protein VP1 into particles
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DOI：
10.1074/jbc.m511261200
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发表时间：
2006-04-14
影响因子：
4.8
通讯作者：
Handa, H
中科院分区：
文献类型：
--
作者：
Kawano, M;Inoue, T;Handa, H
SV40衣壳主要由VP1主衣壳蛋白的72个五聚体组成。尽管衣壳也含有次要的衣壳蛋白VP2及其氨基末端截断形式VP3，但它们在衣壳组装中的作用尚不清楚。利用体外组装系统研究了VP2在重组VP1五聚体组装中的作用。在生理盐和pH条件下，VP1单独游离，在pH 5.0时，VP1组装成管状结构。VP2的化学计量量允许VP1五聚体在7.0至4.0的pH范围内组装成球形颗粒。电镜观察、蔗糖梯度沉降分析和抗体可及性测试表明VP2被并入VP1颗粒中。通过一系列VP2缺失突变体，研究人员进一步探索了VP2中对VP1结合和增强VP1组装重要的功能域。VP3也促进了VP1的组装，并且需要一个与VP2和VP3共同的区域（氨基酸119-272）来促进VP1五聚体的组装。这些结果与体外控制重组衣壳的形成有关，对SV40病毒载体的体外培养有潜在的指导意义。
The SV40 capsid is composed primarily of 72 pentamers of the VP1 major capsid protein. Although the capsid also contains the minor capsid protein VP2 and its amino-terminally truncated form VP3, their roles in capsid assembly remain unknown. An in vitro assembly system was used to investigate the role of VP2 in the assembly of recombinant VP1 pentamers. Under physiological salt and pH conditions, VP1 alone remained dissociated, and at pH 5.0, it assembled into tubular structures. A stoichiometric amount of VP2 allowed the assembly of VP1 pentamers into spherical particles in a pH range of 7.0 to 4.0. Electron microscopy observation, sucrose gradient sedimentation analysis, and antibody accessibility tests showed that VP2 is incorporated into VP1 particles. The functional domains of VP2 important for VP1 binding and for enhancing VP1 assembly were further explored with a series of VP2 deletion mutants. VP3 also enhanced VP1 assembly, and a region common to VP2 and VP3 (amino acids 119-272) was required to promote VP1 pentamer assembly. These results are relevant for controlling recombinant capsid formation in vitro, which is potentially useful for the in vitro development of SV40 virus vectors.