conformational reorganization of the sars coronavirus spike following receptor binding implications for membrane fusion构象重组sars冠状病毒的受体结合后飙升对膜融合的影响.pdfVIP

Conformational Reorganization of the SARS Coronavirus Spike Following Receptor Binding: Implications for Membrane Fusion 1 1 1,2 1,2 1,2 Daniel R. Beniac , Shauna L. deVarennes , Anton Andonov , Runtao He , Tim F. Booth * 1Viral Diseases Division, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada, 2 Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada The SARS coronavirus (SARS-CoV) spike is the largest known viral spike molecule, and shares a similar function with all class 1 viral fusion proteins. Previous structural studies of membrane fusion proteins have largely used crystallography of static molecular fragments, in isolation of their transmembrane domains. In this study we have produced purified, irradiated SARS- CoV virions that retain their morphology, and are fusogenic in cell culture. We used cryo-electron microscopy and image processing to investigate conformational changes that occur in the entire spike of intact virions when they bind to the viral receptor, angiotensin-converting enzyme 2 (ACE2). We have shown that ACE2 binding results in structural changes that appear to be the initial step in viral membrane fusion, and precisely localized the receptor-binding and fusion core domains within the entire spike. Furthermore, our results show that receptor binding and subsequent membrane fusion are distinct steps, and that each spike can bind up to three ACE2 molecules. The SARS-CoV spike provides an ideal model system to study receptor binding and membrane fusion in the native state, employing cryo-electron microscopy and single-particle image analysis. Citation: Beniac DR, deVarennes SL, Andonov A, He R, Booth TF (2007) Conformational Reorganization of the SARS Coronavirus Spike Following Receptor Binding: I