Differential proteolytic activities of precursor and mature forms of the 24K proteinase of grapevine fanleaf nepovirus.
Differential proteolytic activities of precursor and mature forms of the 24K proteinase of grapevine fanleaf nepovirus.
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DOI：
10.1006/viro.1994.1165
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发表时间：
1994-04
期刊：
影响因子：
3.7
通讯作者：
R. Margis;M. Viry;M. Pinck;N. Bardonnet;L. Pinck
中科院分区：
文献类型：
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作者：
R. Margis;M. Viry;M. Pinck;N. Bardonnet;L. Pinck
在基因组RNA5‘端存在基因组连接蛋白(VPG)是不同种类的动植物正义单链RNA病毒的特征。这些病毒通过至少一种病毒蛋白酶顺序处理的多蛋白来表达它们的结构和功能蛋白。葡萄扇叶病毒24K类凝乳杆菌半胱氨酸蛋白酶位于RNA-1编码的多聚蛋白P1的VPG和RNA聚合酶之间，具有游离态和多种前体形式的活性。VPG蛋白水解酶前体(VPG-Pro)是一种稳定的蛋白质，其在网织红细胞裂解物系统中的成熟速度很低。根据所考虑的切割位置的不同，该酶和其VPG-Pro前体形式之间的切割活性存在差异。在多蛋白P2的Arg605/Gly606和Cys257/Ala258位点上，单独的蛋白酶比VPG-Pro具有更高的切割效率。另一方面，推测的Cys415/Ala416位点存在于多蛋白P1的氨基末端，优先被VPG-Pro前体切割。在体外成熟过程中，含有VPG蛋白酶-聚合酶编码区或蛋白酶-聚合酶编码区的蛋白质在切割蛋白酶和RNA聚合酶之间的顺式切割能力上是相似的。
The presence of a genome-linked protein (VPg) at the RNA 5'-end of the genome is a characteristic of different groups of animal and plant positive-sense single-stranded RNA viruses. These viruses express their structural and functional proteins from polyproteins that are sequentially processed by at least one viral proteinase. The grapevine fanleaf nepovirus 24K chymotrypsin-like cysteine proteinase, located between the VPg and the RNA polymerase in the RNA-1 encoded polyprotein P1, is active in its free form and in various precursors forms. The VPg proteinase precursor (VPg-Pro) constitutes a stable protein and its maturation in the reticulocyte lysate system occurs at a very low rate. Differences on cleavage activity were observed between the proteinase and its VPg-Pro precursor forms, depending upon the cleavage site considered. The proteinase alone has a greater cleavage efficiency than VPg-Pro at the Arg605/Gly606 and Cys257/Ala258 sites of polyprotein P2. On the other hand, the presumed Cys415/Ala416 site, present at the amino terminus of polyprotein P1, was preferentially cleaved by the VPg-Pro precursor. During their in vitro maturation, proteins containing the VPg proteinase-polymerase coding region or the proteinase-polymerase region were similar in their ability to cleave in cis between the proteinase and the RNA polymerase.