Fig. 2: Affinity measurement of the impact on the SARS-CoV-2 RBD/hACE2 interaction by swapped RBD subdomains from RaTG13, SARS-CoV-1 and Omicron (B.1.1.529).

A WT SARS-CoV-2’s CR1 subdomain was swapped and the resulting chimeric mutants’ binding to hACE2(1-740) was measured by SPR. Chimeric swapped CR1 mutant from SARS-CoV-1 could not be expressed, which was replaced by a SARS-CoV-2 RBD chimera containing SARS-CoV-1 RBM replacement, binding affinity measurement of which reflects inherent coordination among CR1, CR2 and CR3 subdomains. B WT SARS-CoV-2’s CR2 subdomain was swapped and the resulting chimeric mutants’ binding to hACE2(1-740) was measured by SPR. C WT SARS-CoV-2’s CR3 subdomain was swapped and the resulting chimeric mutants’ binding to hACE2(1-740) was measured by SPR.