The multistep proteolytic maturation pathway utilized by vaccinia virus P4a protein: a degenerate conserved cleavage motif within core proteins.
The multistep proteolytic maturation pathway utilized by vaccinia virus P4a protein: a degenerate conserved cleavage motif within core proteins.
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DOI：
10.1016/0042-6822(91)90976-i
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发表时间：
1991-08
期刊：
影响因子：
3.7
通讯作者：
J. Vanslyke;Stephen S. Whitehead;Elizabeth M. Wilson;Dennis E. Hruby
中科院分区：
文献类型：
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作者：
J. Vanslyke;Stephen S. Whitehead;Elizabeth M. Wilson;Dennis E. Hruby
在病毒粒子中发现的最丰富的痘苗病毒(VV)核心蛋白是蛋白4a，约占粒子干重的14%。4a蛋白被合成为一个102.5 kDa的前体，它被蛋白质降解处理成62 kDa的产物，伴随着病毒粒子的组装。为了确定P4A转化为4A的途径，针对P4A前体亚区的免疫试剂被开发出来，并与肽图和蛋白质测序程序结合使用。结果表明，891个氨基酸的P4A前体在614-615和697-698两个氨基酸残基之间发生裂解。大的氨基端4a蛋白(残基1-614)和羧基末端衍生的23-kDa蛋白(残基698-891)都是病毒粒子的主要组成部分。小肽(残基615-697)的位置和去向尚不清楚。有趣的是，对P4A前体裂解位点预测的氨基酸序列分析表明，在697-698位侧翼存在一个丙氨酸-甘氨酸↓苏氨酸基序，在614-615位侧翼存在一个丙氨酸-甘氨酸↓丝氨酸基序。由于这两种信号都与先前被认为是VV P4b和P25K核心蛋白前体中的裂解点的Ala-Gly↓Ala信号非常相似(VanSlykeet，1991.J.Gen.Viro.72,411-416)，这表明在病毒组装过程中，所有三种核心蛋白前体的加工可能由相同的蛋白酶协调连接和/或催化。
The most abundant vaccinia virus (VV) core protein found within the virion is protein 4a, which represents approximately 14% of the particle's dry weight. The 4a protein is synthesized as a 102.5-kDa precursor, which is proteolytically processed to a 62-kDa product concomitant with virion assembly. To identify the pathway by which P4a is converted into 4a, immunological reagents which are specific for subregions of the P4a precursor were developed and used in concert with peptide mapping and protein sequencing procedures. The result obtained suggest that the 891 amino acid P4a precursor is cleaved at two locations, between residues 614 and 615 and 697 and 698. Both the large amino-terminal 4a protein (residues 1–614) and the carboxy-terminal-derived 23-kDa protein (residues 698–891) become major virion contituents. The location and fate of the small internal peptide (residues 615–697) is not known. Interestingly, an analysis of the predicted amino acid sequences at the sites of cleavage within the P4a precursor indicated the presence of an Ala-Gly ↓ Thr motif flanking the 697–698 site and an Ala-Gly ↓ Ser motif flanking the 614–615 site. Since both of these signals are quite similar to the Ala-Gly ↓ Ala signal previously identified as the cleavage point within the VV P4b and P25K core protein precursors (VanSlykeet al., 1991.J. Gen. Virol.72, 411–416), this suggests that processing of all three core protein precursors may be coordinately linked and/or catalyzed by the same proteinase during viral assembly.