Structural evidence for regulation and specificity of flaviviral proteases and evolution of the Flaviviridae fold
Structural evidence for regulation and specificity of flaviviral proteases and evolution of the Flaviviridae fold
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DOI：
10.1110/ps.072753207
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发表时间：
2007-05-01
期刊：
影响因子：
8
通讯作者：
Liddington, Robert C.
中科院分区：
文献类型：
--
作者：
Aleshin, Alexander E.;Shiryaev, Sergey A.;Liddington, Robert C.
黄病毒家族的致病成员，包括西尼罗河病毒(WNV)和登革病毒(DV)，是日益严重的全球威胁，目前还没有具体的治疗方法。双组分黄病毒酶NS2B-NS3裂解宿主细胞内的病毒多蛋白前体，这是病毒复制所必需的过程。在这里，我们报告了WNV NS2B-NS3Pro在无底物形式和与胰蛋白酶抑制剂抑肽酶/BPTI复合体中的晶体结构。我们发现抑肽酶以一种底物模拟的方式结合，其中蛋白酶的生产构象完全形成，这为“诱导匹配”的催化机制提供了证据，并使我们能够使WNV和DV蛋白酶的不同底物特异性合理化。我们还表明，西尼罗河病毒的NS2B辅因子可以采用两种非常不同的构象，这可能是黄病毒蛋白水解酶的一个普遍特征，为进一步的调控提供了机会。最后，通过将黄病毒蛋白水解酶与亲缘关系更远的丙型肝炎病毒进行比较，我们对黄病毒折叠的进化提供了见解。我们的工作应该加快设计蛋白酶抑制剂来治疗一系列黄病毒感染。
Pathogenic members of the flavivirus family, including West Nile Virus ( WNV) and Dengue Virus ( DV), are growing global threats for which there are no specific treatments. The two- component flaviviral enzyme NS2B-NS3 cleaves the viral polyprotein precursor within the host cell, a process that is required for viral replication. Here, we report the crystal structure of WNV NS2B-NS3pro both in a substrate-free form and in complex with the trypsin inhibitor aprotinin/ BPTI. We show that aprotinin binds in a substrate- mimetic fashion in which the productive conformation of the protease is fully formed, providing evidence for an `` induced fit'' mechanism of catalysis and allowing us to rationalize the distinct substrate specificities of WNVand DV proteases. We also show that the NS2B cofactor of WNV can adopt two very distinct conformations and that this is likely to be a general feature of flaviviral proteases, providing further opportunities for regulation. Finally, by comparing the flaviviral proteases with the more distantly related Hepatitis C virus, we provide insights into the evolution of the Flaviviridae fold. Our work should expedite the design of protease inhibitors to treat a range of flaviviral infections.