Figure 5
High-resolution SEC-UPLC analysis. Ancestral and Beta trimer binding to (A) ACE2 receptor, (B) anti-RBD CR3022 antibody, (C) anti-S2 511 antibody. While saturation at 3 × molar excess antibody was observed for ancestral trimer (shift in retention time and peak shape), incubation of Beta trimer with the same anti-S2 511 antibody did not result in similar shifts in the chromatographic profile even up to a 12 × molar excess (data not shown). All conditions were held at 2 to 8 °C for SEC-UPLC analysis. Response of ACE2 only control trace (grey) was normalized to spike protein only (blue) to allow for visualization. The recombinant ACE2 elutes as two separate peaks with the homodimer eluting at approximately 5.4 min and the dimer of homodimer eluting earlier at 5.0 min.
