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. Author manuscript; available in PMC: 2012 May 10.
Published in final edited form as: Virology. 2011 Mar 23;413(2):265–274. doi: 10.1016/j.virol.2011.02.020

Fig. 2.

Fig. 2

Role of R667 and K672 in SARS-CoV entry and inactivation. (A) Infectivity of pseudovirions bearing wild-type SARS-S and SARS-S variants R667A or K672L or no envelope protein (control) for VeroE6 cells. Results are presented as means and standard deviations of triplicate wells. Similar results were seen in 293T and 293T-ACE2 cells. (B) Expression of SARS-S and mutant SARS-S-proteins on pseudovirions. Equal volumes of virus stocks were concentrated by ultracentrifugation through a sucrose gradient, treated with PBS or trypsin and spike-proteins were detected using a monoclonal antibody directed against the N-terminal portion of SARS-S. (C) Trypsin inactivation of pseudotypes bearing SARS-S or mutant SARS-S proteins. Ultracentrifuge-concentrated virus was pretreated with varying concentrations of TPCK-trypsin for 10 min at 25°C, before trypsin inactivation and spin infection of 293T-ACE2 cells. Results are presented relative to infectivity measured for untreated virions and are means and standard deviations of triplicate wells. (D) Inactivation of SARS-S and SARS-S mutant R667A by various proteases prior to infection of 293T-ACE2 cells. Results are presented relative to the infectivity measured for untreated viruses and are means and standard deviations of triplicate wells. Similar results were seen in two additional experiments.