中文摘要：

目的: 登革热是登革热病毒(DENV ) 引起感染，没有有效治疗为是可得到的严重流行疾病。朊酶建筑群，由 nonstructural 蛋白质 3 组成(NS3 ) 并且它的余因子 NS2B，在 DENV 的复制起一个枢轴的作用，可以因此是为 anti-DENV 药的一个潜在的目标。这里，我们报导 DENV2 NS2B/NS3 朊酶和它的抗病毒的行动的一个新奇禁止者。

英文摘要：

Aim： Dengue is a severe epidemic disease caused by dengue virus （DENV） infection, for which no effective treatment is available. The protease complex, consisting of nonstructural protein 3 （NS3） and its cofactor NS2B, plays a pivotal role in the replication of DENV, thus may be a potential target for anti-DENY drugs. Here, we report a novel inhibitor of DENY2 NS2B/NS3 protease and its antiviral action. Methods： An enzymatic inhibition assay was used for screening DENY2 NS2B/NS3 inhibitors. Cytotoxicity to BHK-21 cells was assessed with MTT assay. Antiviral activity was evaluated in BHK-21 cells transfected with Rlu-DENV-Rep. The molecular mechanisms of the antiviral action was analyzed using surface plasmon resonance, ultraviolet-visible spectral analysis and differential scanning calorimetry assays, as well as molecular docking analysis combined with site-directed mutagenesis. Results： In our in-house library of old drugs （NIO00 compounds）, a topical hemostatic and antiseptic 2-hydroxy-3,5-bis[（4-hydroxy- 2-methyl-5-sulfophenyl）methyl]-4-methyl-benzene-sulfonic acid （policresulen） was found to be a potent inhibitor of DENV2 NS2B/NS3 protease with ICso of 0.48 pg/mL. Furthermore, policresulen inhibited DENV2 replication in BHK-21 cells with ICso of 4,99 pg/mL, whereas its IC50 for cytotoxicity to BHK-21 cells was 459.45 pg/mL. Policresulen acted as a competitive inhibitor of the protease, and slightly affected the protease stability. Using biophysical technology-based assays and molecular docking analysis combined with site- directed mutagenesis, we demonstrated that the residues Gin106 and Arg133 of DENV2 NS2B/NS3 protease directly interacted with policresulen via hydrogen bonding. Conclusion： Policresulen is a potent inhibitor of DENY2 NS2B/NS3 protease that inhibits DENV2 replication in BHK-21 cells. The bind- ing mode of the protease and policresulen provides useful hints for designing new type of inhibitors against the protease.