与戊型肝炎病毒假定的木瓜蛋白酶样半胱氨酸蛋白酶相关的去泛素化活性。
Deubiquitination activity associated with hepatitis E virus putative papain-like cysteine protease.
机构信息
Hepatitis Division, National Institute of Virology, Microbial Containment Complex, Sus Road, Pashan, Pune 411021, India.
出版信息
J Gen Virol. 2011 Sep;92(Pt 9):2088-2092. doi: 10.1099/vir.0.033738-0. Epub 2011 Jun 8.
Hepatitis E virus (HEV) ORF1 protein (pORF1) contains methyltransferase (MetT), papain-like cysteine protease (PCP), RNA helicase (Hel) and RNA-dependent RNA polymerase (RdRp) domains. ORF1 sequence analysis showed two consensus LXGG cleavage sites at 664 and 1205. LXGG sequence is recognized by viral and cellular deubiquitinating enzymes. The protein encompassing the predicted MetT-PCP domains of HEV ORF1 was tested for deubiquitinating activity using fluorogenic substrates - ubiquitin-7-amino-4-methylcoumarin (AMC), IFN-stimulated gene 15 (ISG15)-AMC, Nedd8-AMC and SUMO-AMC. MetT-PCP cleaved all four substrates but processing of ISG15-AMC was more robust. There was no processing of the Hel and RdRp domains having the conserved (1205) LXGG site by the protein. MetT-PCP carried out deISGylation of the ISG15-conjugated cellular proteins, suggesting a possible role in combating cellular antiviral pathways.
戊型肝炎病毒 (HEV) ORF1 蛋白 (pORF1) 包含甲基转移酶 (MetT)、木瓜样半胱氨酸蛋白酶 (PCP)、RNA 解旋酶 (Hel) 和 RNA 依赖性 RNA 聚合酶 (RdRp) 结构域。ORF1 序列分析显示在 664 和 1205 位有两个保守的 LXGG 切割位点。LXGG 序列被病毒和细胞去泛素化酶识别。使用荧光底物——泛素-7-氨基-4-甲基香豆素 (AMC)、干扰素刺激基因 15 (ISG15)-AMC、Nedd8-AMC 和 SUMO-AMC，对 HEV ORF1 的预测 MetT-PCP 结构域的蛋白进行去泛素化活性测试。MetT-PCP 切割了所有四种底物，但 ISG15-AMC 的加工更有效。该蛋白未对具有保守 (1205) LXGG 位点的 Hel 和 RdRp 结构域进行加工。MetT-PCP 对 ISG15 缀合的细胞蛋白进行去泛素化，表明其在对抗细胞抗病毒途径中可能发挥作用。
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