Slack J M, Kuzio J, Faulkner P
Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada.
J Gen Virol. 1995 May;76 ( Pt 5):1091-8. doi: 10.1099/0022-1317-76-5-1091.
Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) contains a 966 bp ORF that encodes a papain type cysteine proteinase with cathepsin L-like characteristics. Using Western blot analysis of infected cell extracts we showed that v-cath proteinase has 35.5 kDa and 32 kDa precursor forms which are processed to a 27.5 kDa mature form in a manner characteristic of papain and cathepsin L. V-cath proteinase activity was greatest under acidic conditions (pH 5.0) and was reduced in the presence of the cysteine proteinase inhibitors, leupeptin and E64. Urea, a known enhancer of cathepsin L activity, also enhanced v-cath proteinase activity. AcMNPV v-cath proteinase was detected post-mortem in tissues of insects infected with wild-type (wt) virus. Insects infected with a v-cath deletion mutant did not become flaccid after death as is normally observed with wt AcMNPV infections. These findings indicate a link between v-cath activity and degradation of host tissues during virus pathogenesis.
苜蓿银纹夜蛾多核型多角体病毒（AcMNPV）含有一个966 bp的开放阅读框，该阅读框编码一种具有组织蛋白酶L样特征的木瓜蛋白酶型半胱氨酸蛋白酶。通过对感染细胞提取物进行蛋白质免疫印迹分析，我们发现v-cath蛋白酶具有35.5 kDa和32 kDa的前体形式，它们以木瓜蛋白酶和组织蛋白酶L的特征方式加工成27.5 kDa的成熟形式。v-cath蛋白酶活性在酸性条件下（pH 5.0）最高，在存在半胱氨酸蛋白酶抑制剂亮抑酶肽和E64时活性降低。尿素是一种已知的组织蛋白酶L活性增强剂，也能增强v-cath蛋白酶活性。在感染野生型（wt）病毒的昆虫组织中，死后检测到AcMNPV v-cath蛋白酶。感染v-cath缺失突变体的昆虫死后不会像野生型AcMNPV感染时通常观察到的那样变得松弛。这些发现表明v-cath活性与病毒发病机制期间宿主组织的降解之间存在联系。
