Conformational Changes in Human Hepatitis C Virus NS3 Protease upon Binding of Product-Based Inhibitors
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- 作者：Elisabetta Bianchi ; Stefania Orrù ; Fabrizio Dal Piaz ; Raffaele Ingenito ; Annarita Casbarra ; Gabriella Biasiol ; Uwe Koch ; Piero Pucci ; and Antonello Pessi
- 刊名：Biochemistry
- 出版年：1999
- 出版时间：October 19, 1999
- 年：1999
- 卷：38
- 期：42
- 页码：13844 - 13852
- 全文大小：139K
- 年卷期：v.38,no.42(October 19, 1999)
- ISSN：1520-4995
文摘
One of the most promising approaches to anti-hepatitis C virus drug discovery is thedevelopment of inhibitors of the virally encoded protease NS3. This chymotrypsin-like serine protease isessential for the maturation of the viral polyprotein, and processing requires complex formation betweenNS3 and its cofactor NS4A. Recently, we reported on the discovery of potent cleavage product-derivedinhibitors [Ingallinella et al. (1998) Biochemistry 37, 8906-8914]. Here we study the interaction of theseinhibitors with NS3 and the NS3/cofactor complex. Inhibitors bind NS3 according to an induced-fitmechanism. In the absence of cofactor different binding modes are apparent, while in the presence ofcofactor all inhibitors show the same binding mode with a small rearrangement in the NS3 structure, assuggested by circular dichroism spectroscopy. These data are consistent with the hypothesis that NS4Acomplexation induces an NS3 structure that is already (but not entirely) preorganized for substrate bindingnot only for what concerns the S' site, as already suggested, but also for the S site. Inhibitor binding tothe NS3/cofactor complex induces the stabilization of the enzyme structure as highlighted by limitedproteolysis experiments. We envisage that this may occur through stabilization of the individual N-terminaland C-terminal domains where the cofactor and inhibitor, respectively, bind and subsequent tightening ofthe interdomain interaction in the ternary complex.