DRUG DESIGINS OF INHIBITORS TARGETED TO REPLICASE AND REPLICATION OF HEPATITIS C VIRUS (HCV)

由于抑制HCV复制有望减少甚至阻断HCV相关肝细胞癌的发病率，HCV NS5B， arna依赖性RNA聚合酶，可能是抑制HCV复制的药物设计的一个强有力的靶点。主要结果如下。1)新发现NS5B的5个残基对RNA依赖性RNA合成（RdRP）活性至关重要。2)其中两个远离RdRP催化中心的残基被指定为NS5B寡聚不可缺少的残基。NS5B的寡聚化是NS5B的RdRP活性的先决条件，这表明这两个残基是残基特异性的，并且可以交换寡聚化和RdRP活性。3)表征了NS5A与NS5B的特异性相互作用，发现NS5A在体外可通过直接相互作用调节RdRP活性。4)发现核仁蛋白直接与NS5B结合，当c端膜附着结构域被截断时影响NS5B的亚细胞定位。NS5B的这些相互作用表面可能是抑制HCV复制的药物设计的靶点。

As inhibition of HCV replication is expected to reduce or even block incidence of HCV-associated hepatocellular carcinoma, HCV NS5B, aRNA-dependent RNA polymerase, might be a strong target for drug designs to inhibit HCV replication. The main results are followings. 1) 5 residues of NS5B were newly identified to be critical for RNA-dependent RNA synthesis (RdRP) activity. 2)Two residues among them located far from the RdRP catalytic center were specified to be indispensable ones for oligomerization of NS5B. The oligomerization of NS5B was found to be prerequisite to RdRP activity of NS5B by demonstrating that the two residues are residue-specific and exchangeable for oligomerization and RdRP activities. 3)Specific interaction between NS5A and NS5B was characterized, and we found that NS5A can modulate RdRP activity through the direct interaction in vitro. 4) Nucleolin, was found to bind directly to NS5B and affected subcellular localization of NS5B when the C-terminal membrane-attachment domain was truncated. These interaction surfaces of NS5B would be putative targets for drug designs to inhibit HCV replication.