Characterization of the Prefusion and Transition States of Severe Acute Respiratory Syndrome Coronavirus S2-HR2

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• 作者：Susanna McReynolds ; Shaokai Jiang ; Ying Guo ; Jessica Celigoy ; Christine Schar ; Lijun Rong ; Michael Caffrey
• 刊名：Biochemistry
• 出版年：2008
• 出版时间：July 1, 2008
• 年：2008
• 卷：47
• 期：26
• 页码：6802 - 6808
• 全文大小：1112K
• 年卷期：v.47,no.26(July 1, 2008)
• ISSN：1520-4995

文摘

The envelope glycoproteins of the class I family, which include human immunodeficiency virus (HIV), influenza, and severe acute respiratory syndrome coronavirus (SARS-CoV), mediate viral entry by first binding to their cellular receptors and subsequently inducing fusion of the viral and cellular membranes. In the case of SARS-CoV, heptad repeat domains of the envelope glycoprotein, termed S2-HR1 and S2-HR2, are thought to undergo structural changes from a prefusion state, in which S2-HR1 and S2-HR2 do not interact, to a postfusion state in which S2-HR1 and S2-HR2 associate to form a six-helix bundle. In the present work, the structural and dynamic properties of S2-HR2 have been characterized. Evidence is presented for an equilibrium between a structured trimer thought to represent a prefusion state and an ensemble of unstructured monomers thought to represent a novel transition state. A model for viral entry is presented in which S2-HR2 is in a dynamic equilibrium between an ensemble of unstructured monomers in the transition state and a structured trimer in the prefusion state. Conversion from the prefusion state to the postfusion state requires passage through the transition state, a state that may give insight into the design of structure-based antagonists of SARS-CoV in particular, as well as other enveloped viruses in general.