A conserved leucine that constricts the pore through the capsid fivefold cylinder plays a central role in parvoviral infection
A conserved leucine that constricts the pore through the capsid fivefold cylinder plays a central role in parvoviral infection
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DOI：
10.1016/j.virol.2004.03.006
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发表时间：
2004-06-01
期刊：
影响因子：
3.7
通讯作者：
Tattersall, P
中科院分区：
文献类型：
--
作者：
Farr, GA;Tattersall, P
小鼠细小病毒微小病毒（MVM）的含有DNA的T = 1颗粒的原子结构显示在每个五重对称轴处的圆柱形突起，每个突起含有8埃孔，单个VP 2 N末端的10个氨基酸穿过该孔。该孔的最紧密的收缩在其内端由来自5个独立的VP 2分子的位置172的亮氨酸侧链的并置形成。为了测试L172是否调节VP N-末端的挤出，我们构建并分析了在这个高度保守的残基处的一整套氨基酸取代突变体。除了一个突变体外，所有突变体都产生了含有DNA的病毒体，但只有两个，L172 V和L1721，是感染性的，其他的被阻止病毒进入。一些突变体在39 ℃下组装有明显缺陷，但在32 ℃下没有。L172 W显著削弱了基因组的折叠，表明五倍圆柱体也可能是DNA包装的门户。虽然胰蛋白酶切割的`VP 2 N-末端不受影响的突变体，VP 1被降解的突变体，而不是野生型，病毒粒子的蛋白水解过程中。(C)2004年爱思唯尔公司All rights reserved.
The atomic structure of the DNA-containing T = 1 particle of the parvovirus minute virus of mice (MVM) reveals cylindrical projections at each fivefold symmetry axis, each containing an 8 Angstrom pore through which runs 10 amino acids of a single VP2 N-tenninus. The tightest constriction of this pore is formed at its inner end by the juxtaposition of leucine side chains from position 172 of five independent VP2 molecules. To test whether L172 modulates the extrusion of VP N-termini, we constructed and analyzed a complete set of amino acid substitution mutants at this highly conserved residue. All but one mutant produced DNA-containing virions, but only two, L172V and L 1721, were infectious, the others being blocked for viral entry. Several mutants were significantly defective for assembly at 39 degreesC, but not at 32 degreesC. L172W significantly impaired genome encapsidation, indicating that the fivefold cylinder may also be the DNA packaging portal. Although tryptic cleavage of the `VP2 N-tenninus was not affected for the mutants, VP1 was degraded during proteolysis of mutant, but not wild-type, virions. (C) 2004 Elsevier Inc. All rights reserved.