Fig. 6.

Effect of GB-1 on interaction between ACE2 and RBD with E484K mutation. Flow cytometry analysis of ACE2-Spike protein binding. (A) 293 T cells with pCEP4-myc-ACE2 plasmid were incubated with RBD (E484K)-sfGFP-containing medium and co-stained with fluorescent anti-MYC Alexa 647 to detect surface ACE2 by flow cytometry. During analysis, the top population were chosen from the ACE2-positive population. Then, two subsets of the ACE2-positive population were collected: the top population (nCoV-S-High sort, red gate) and the bottom population (nCoV-S-Low sort, green gate) based on the fluorescence of bound RBD (E484K)-sfGFP relative to ACE2 surface expression. (B) Quantitative results of nCoV-S-High sort and nCoV-S-low sort, which were presented as ratio compared with blank, in the top population or ACE2-positive population. All the results are representative of at least three independent experiments. (Error bars=mean±S.E.M. Asterisks (*) mark samples significantly different from control group with p < 0.05).