Nowak T, Färber P M, Wengler G, Wengler G
Institut für Virologie, Justus-Liebig-Universität Giessen, Federal Republic of Germany.
Virology. 1989 Apr;169(2):365-76. doi: 10.1016/0042-6822(89)90162-1.
The proteolytic processes involved in the synthesis of the structural proteins of the West Nile (WN) flavivirus were analyzed: The carboxy-terminal sequences of the structural proteins were determined and the proteins translated in vitro in the presence of membranes from a mRNA coding for the structural polyprotein were analyzed. The results obtained indicate that the following proteolytic activities are involved in the synthesis and assembly of WN virus structural proteins: The growing peptide chain which contains the sequences of the structural proteins in the order C-pre-M-E is cleaved at three places by cellular signalase(s). This cleavage generates the primary amino acid sequence of the mature structural proteins pre-M and E (and the amino-terminus of the ensuing nonstructural protein NS 1). The amino-terminal part of the polyprotein containing the amino acid residues 1 to 123 is released as a molecule which migrates slightly slower than the mature viral core protein and which presumably is associated to the RER membranes via its carboxy-terminal sequence. This protein is called the anchored C virus particles the anchored C protein is converted into mature C protein by removal of the carboxy-terminal hydrophobic segment containing the amino acid residues 106 to 123. Presumably a virus-coded protease which can cleave the polyprotein after two basic amino acid residues is responsible for this cleavage. The cell-associated WN virus particles are constructed from the proteins C, pre-M, and E which contain the amino residues 1-105, 124-290, and 291-787 of the polyprotein, respectively. Cleavage of the pre-M protein between amino acid residues 215 and 216, presumably by a cellular enzyme located in the Golgi vesicles, and loss of the amino-terminal fragment of this protein are associated with the release of virus from the cells.
分析了西尼罗河（WN）黄病毒结构蛋白合成过程中的蛋白水解过程：确定了结构蛋白的羧基末端序列，并分析了在编码结构多蛋白的mRNA存在下，在膜存在的情况下体外翻译的蛋白质。所得结果表明，以下蛋白水解活性参与WN病毒结构蛋白的合成和组装：包含结构蛋白序列（顺序为C-pre-M-E）的正在生长的肽链在三个位置被细胞信号肽酶切割。这种切割产生了成熟结构蛋白pre-M和E（以及随后的非结构蛋白NS 1的氨基末端）的一级氨基酸序列。多蛋白的氨基末端部分包含氨基酸残基1至123，作为一个分子释放，其迁移速度略慢于成熟病毒核心蛋白，并且可能通过其羧基末端序列与糙面内质网（RER）膜相关联。这种蛋白被称为锚定C蛋白。病毒颗粒中的锚定C蛋白通过去除包含氨基酸残基106至123的羧基末端疏水片段而转化为成熟C蛋白。据推测，一种能在两个碱性氨基酸残基后切割多蛋白的病毒编码蛋白酶负责这种切割。与细胞相关的WN病毒颗粒由分别包含多蛋白的氨基酸残基1-105、124-290和291-787的蛋白C、pre-M和E构建而成。pre-M蛋白在氨基酸残基215和216之间的切割，可能是由位于高尔基体囊泡中的一种细胞酶进行的，该蛋白氨基末端片段的丢失与病毒从细胞中的释放有关。
