A 2ND PROTEINASE ENCODED BY A PLANT POTYVIRUS GENOME
A 2ND PROTEINASE ENCODED BY A PLANT POTYVIRUS GENOME
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DOI：
10.1002/j.1460-2075.1989.tb03386.x
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发表时间：
1989-02-01
期刊：
影响因子：
11.4
通讯作者：
DOUGHERTY, WG
中科院分区：
文献类型：
--
作者：
CARRINGTON, JC;CARY, SM;DOUGHERTY, WG
烟草蚀纹病毒 (TEV) 的 RNA 基因组编码一种大的多蛋白前体，该前体被病毒特异性蛋白酶加工成成熟蛋白质。位于多蛋白羧基末端三分之二内的切割位点由 TEV 编码的 49 kd 蛋白酶进行加工，而负责切割其余位点的酶尚未被发现。在这项研究中，基于确定的 RNA 转录本的无细胞表达，鉴定出了第二种 TEV 编码的蛋白酶。该蛋白酶的边界已通过缺失分析和定点突变确定。蛋白水解活性结构域已定位于 56 kd 蚜虫传播辅助组件的羧基末端一半。已在与该酶的羧基末端相邻的多蛋白中鉴定出该蛋白酶识别的切割位点，并且该蛋白酶似乎通过自催化机制进行切割。体外蛋白水解发生在 Gly-GLy 二肽之间，通过蛋白水解产物氨基末端的放射化学测序确定。
The RNA genome of tobacco etch virus (TEV) encodes a large polyprotein precursor that is processed to mature proteins by virus-specific proteinases. Cleavage sites located within the carboxyl-terminal two-thirds of the polyprotein are processed by a TEV-encoded 49 kd proteinase, while the enzyme(s) responsible for cleaving the remaining sites has not been found. In this study, a second TEV-encoded proteinase has been identified based on cell-free expression of defined RNA transcripts. The boundaries of this proteinase have been delineated by deletion analysis and site-directed mutagenesis. The proteolytically active domain has been localized to the carboxyl-terminal half of the 56 kd aphid transmission helper component. A cleavage site tht is recognized by this proteinase has been identified in the polyprotein adjacent to the carboxyl-terminus of the enzyme, and the proteinase appears to cleave by an autocatalytic mechanism. Proteolysis in vitro occurs between a Gly-GLy dipeptide as determined by radiochemical sequencing at the amino-terminus of the proteolytic product.