SITE-DIRECTED MUTATION AFFECTING POLYOMAVIRUS CAPSID SELF-ASSEMBLY INVITRO
SITE-DIRECTED MUTATION AFFECTING POLYOMAVIRUS CAPSID SELF-ASSEMBLY INVITRO
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DOI：
10.1038/329086a0
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发表时间：
1987-09-03
期刊：
影响因子：
64.8
通讯作者：
CASPAR, DLD
中科院分区：
文献类型：
--
作者：
GARCEA, RL;SALUNKE, DM;CASPAR, DLD
相同蛋白质亚基的非等价键合发生在多瘤病毒衣壳中，其中相同的五聚体衣壳占据二十面体表面晶格中的六价和五价位置1。在大肠杆菌中表达重组基因后纯化的多瘤病毒主要衣壳蛋白VP1 2已被分离为在体外自组装成衣壳样结构的衣壳3。因此，在不同的对称环境中转换结合特异性的能力必须是VP1分子固有的。我们在这里报告，在VP1表达载体中的定向突变，导致在羧基末端截短的蛋白质，导致在体外组装试验中形成衣壳而不是衣壳的突变体VP1。因此，VP1的羧基末端似乎参与了负责壳粒非等价结合的特异性结合。
Nonequivalent bonding of identical protein subunits occurs in the polyomavirus capsid where identical pentameric capsomeres occupy both hexavalent and pentavalent positions in the icosahedral surface lattice1. The polyomavirus major capsid protein VP1, purified after expression of the recombinant gene inEscherichia coli2, has been isolated as capsomeres that self-assemble into capsid-like structures invitro3. The ability to switch bonding specificity in different symmetry environments therefore must be intrinsic to the VP1 molecule.In vitroself-assembly provides an assay for VP1 mutations affecting capsomere and capsid formation. We report here that a directed mutation in the VP1 expression vector, leading to a protein truncated at the carboxy terminus, results in a mutant VP1 that forms capsomeres, but not capsids, in the invitroassembly assay. The carboxy terminus of VP1 therefore appears to be involved in the specific bonding responsible for the non-equivalent association of capsomeres.