Kuang Wan-Fen, Lin Yu-Chieh, Jean François, Huang Yu-Wen, Tai Chun-Ling, Chen Ding-Shinn, Chen Pei-Jer, Hwang Lih-Hwa
Graduate Institute of Microbiology, National Taiwan University College of Medicine, Taipei, Taiwan, ROC.
Biochem Biophys Res Commun. 2004 Apr 23;317(1):211-7. doi: 10.1016/j.bbrc.2004.03.032.
To determine whether the two domains of hepatitis C virus (HCV) NS3 and the NS4A interact with each other to regulate the RNA unwinding activity, this study compares the RNA unwinding, ATPase and RNA binding activities of three forms of NS3 proteins--the NS3H protein, containing only the helicase domain, the full-length NS3 protein, and the NS3-NS4A complex. The results revealed that NS3 displayed the weakest RNA helicase activity, not because it had lower ATPase or RNA binding activity than did NS3H or NS3-NS4A, but because it had the lowest RNA unwinding processivity. A mutant protein, R1487Q, which contained a mutation in the helicase domain, displayed a reduced protease activity as compared to the wild-type NS3-NS4A. Together, these results suggest the existence of interactions between the two domains of NS3 and the NS4A, which regulates the HCV NS3 protease and RNA helicase activities.
为了确定丙型肝炎病毒（HCV）NS3的两个结构域与NS4A是否相互作用以调节RNA解旋活性，本研究比较了三种形式的NS3蛋白的RNA解旋、ATP酶和RNA结合活性，这三种形式分别是：仅包含解旋酶结构域的NS3H蛋白、全长NS3蛋白以及NS3-NS4A复合物。结果显示，NS3的RNA解旋酶活性最弱，并非因为其ATP酶或RNA结合活性低于NS3H或NS3-NS4A，而是因为其RNA解旋持续性最低。一种在解旋酶结构域含有突变的突变蛋白R1487Q，与野生型NS3-NS4A相比，其蛋白酶活性降低。总之，这些结果表明NS3的两个结构域与NS4A之间存在相互作用，这种相互作用调节了HCV NS3蛋白酶和RNA解旋酶活性。
