Capsids and Portals Influence Each Other's Conformation During Assembly and Maturation
Capsids and Portals Influence Each Other's Conformation During Assembly and Maturation
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DOI：
10.1016/j.jmb.2020.01.022
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发表时间：
2020-03-27
影响因子：
5.6
通讯作者：
Duda, Robert L.
中科院分区：
文献类型：
--
作者：
Maurer, Joshua B.;Oh, Bonnie;Duda, Robert L.
尾噬菌体和疱疹病毒衣壳的门户蛋白形成占据一个衣壳顶点的十二聚体环，并在称为原衣壳或前头的衣壳前体组装期间并入。门户是必不可少的，并作为DNA运输的孔和尾部附着的位点;然而，噬菌体HK 97衣壳蛋白在从质粒表达时无需门户即可高效组装。在门户网站共表达之后，门户网站被纳入了大约一半的proheads中。在没有活性衣壳成熟蛋白酶的情况下，未切割的proheads在纯化过程中形成proheads的二聚体、三聚体和四聚体，但仅当它们具有门户时。这些似乎通过其门户与膜样片段结合，并且可以被去污剂分解，支持膜在其形成和衣壳组装中的作用。在细胞提取物中检测到前体寡聚体的前体。这些能够结合到辛基琼脂糖凝胶，并可以通过洗涤剂释放，而未切割的proheads没有门户网站或切割proheads门户网站不结合。我们的研究结果记录了一个离散的变化，在香港97门户网站的疏水性诱导裂解的原衣壳壳，它嵌入。此外，我们检测到的门户网站复杂的存在下，裂解的HK 97 proheads诱导的扩展速度增加。这些结果表明，门户网站和衣壳在组装过程中相互影响的构象。前头部寡聚体的形成还提供了用于鉴定和分析门静脉掺入突变体的快速和灵敏的测定。(C)2020爱思唯尔有限公司版权所有。
The portal proteins of tailed bacteriophage and Herpesvirus capsids form dodecameric rings that occupy one capsid vertex and are incorporated during the assembly of capsid precursors called procapsids or proheads. Portals are essential and serve as the pore for DNA transit and the site of tail attachment; however, bacteriophage HK97 capsid proteins assemble efficiently without a portal when expressed from plasmids. Following portal co-expression, portals were incorporated into about half of the proheads that were made. In the absence of active capsid maturation protease, uncleaved proheads formed dimers, trimers, and tetramers of proheads during purification, but only if they had portals. These appeared bound to membrane-like fragments by their portals and could be disaggregated by detergents, supporting a role for membranes in their formation and in capsid assembly. The precursors to prohead oligomers were detected in cell extracts. These were able to bind to Octyl-Sepharose and could be released by detergent, while uncleaved proheads without portal or cleaved proheads with portal did not bind. Our results document a discrete change in the HK97 portal's hydrophobicity induced by cleavage of the procapsid shell in which it is embedded. Additionally, we detected an increase in the rate of expansion induced by the presence of a portal complex in cleaved HK97 proheads. These results suggest that portals and capsids influence each other's conformation during assembly. The formation of prohead oligomers also provides a rapid and sensitive assay for identification and analysis of portal incorporation mutants. (C) 2020 Elsevier Ltd. All rights reserved.