THE 5' END OF THE EQUINE ARTERITIS VIRUS REPLICASE GENE ENCODES A PAPAIN-LIKE CYSTEINE PROTEASE
THE 5' END OF THE EQUINE ARTERITIS VIRUS REPLICASE GENE ENCODES A PAPAIN-LIKE CYSTEINE PROTEASE
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DOI：
10.1128/jvi.66.12.7040-7048.1992
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发表时间：
1992-12-01
影响因子：
5.4
通讯作者：
SPAAN, WJM
中科院分区：
文献类型：
--
作者：
SNIJDER, EJ;WASSENAAR, ALM;SPAAN, WJM
马动脉炎病毒（EAV）复制酶n端存在木瓜样半胱氨酸蛋白酶（PCP）结构域，这是基于与细胞和病毒硫醇蛋白酶有限的序列相似性而假设的，已通过体外翻译和诱变研究得到证实。发现EAV蛋白酶在其C端引导自蛋白水解裂解，导致产生约30 kda的n端复制酶产物（nsp1），其中包含PCP结构域。EAV复制酶多蛋白的氨基酸残基Cys-164和His-230被确定为最有可能的PCP催化残基。通过对细菌表达系统中PCP裂解产物的n端序列分析，表明Gly-260和Gly-261之间存在裂解。没有证据表明在EAV复制酶的其他位置存在pcp定向切割。在共译和翻译后反式切割实验中，EAV nsp1及其前体都不能在反式中处理PCP切割位点。
The presence of a papainlike cysteine protease (PCP) domain in the N-terminal region of the equine arteritis virus (EAV) replicase, which had been postulated on the basis of limited sequence similarities with cellular and viral thiol proteases, was confirmed by in vitro translation and mutagenesis studies. The EAV protease was found to direct an autoproteolytic cleavage at its C terminus which leads to the production of an approximately 30-kDa N-terminal replicase product (nsp1) containing the PCP domain. Amino acid residues Cys-164 and His-230 of the EAV replicase polyprotein were identified as the most likely candidates for the role of PCP catalytic residues. By means of N-terminal sequence analysis of a PCP cleavage product, derived from a bacterial expression system, it was shown that cleavage occurs between Gly-260 and Gly-261. No evidence for PCP-directed cleavages at other positions in the EAV replicase was obtained. In cotranslational and posttranslational trans-cleavage assays, neither EAV nsp1 nor its precursor was able to process the PCP cleavage site in trans.