Deep mutational scans for ACE2 binding, RBD expression, and antibody escape in the SARS-CoV-2 Omicron BA.1 and BA.2 receptor-binding domains.
SARS-CoV-2 continues to acquire mutations in the spike receptor-binding domain (RBD) that impact ACE2 receptor binding, folding stability, and antibody recognition. Deep mutational scanning prospectively characterizes the impacts of mutations on these biochemical properties, enabling rapid assessmen...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2022-11-01
|
| Series: | PLoS Pathogens |
| Online Access: | https://doi.org/10.1371/journal.ppat.1010951 |
| _version_ | 1797848191189647360 |
|---|---|
| author | Tyler N Starr Allison J Greaney Cameron M Stewart Alexandra C Walls William W Hannon David Veesler Jesse D Bloom |
| author_facet | Tyler N Starr Allison J Greaney Cameron M Stewart Alexandra C Walls William W Hannon David Veesler Jesse D Bloom |
| author_sort | Tyler N Starr |
| collection | DOAJ |
| description | SARS-CoV-2 continues to acquire mutations in the spike receptor-binding domain (RBD) that impact ACE2 receptor binding, folding stability, and antibody recognition. Deep mutational scanning prospectively characterizes the impacts of mutations on these biochemical properties, enabling rapid assessment of new mutations seen during viral surveillance. However, the effects of mutations can change as the virus evolves, requiring updated deep mutational scans. We determined the impacts of all single amino acid mutations in the Omicron BA.1 and BA.2 RBDs on ACE2-binding affinity, RBD folding, and escape from binding by the LY-CoV1404 (bebtelovimab) monoclonal antibody. The effects of some mutations in Omicron RBDs differ from those measured in the ancestral Wuhan-Hu-1 background. These epistatic shifts largely resemble those previously seen in the Alpha variant due to the convergent epistatically modifying N501Y substitution. However, Omicron variants show additional lineage-specific shifts, including examples of the epistatic phenomenon of entrenchment that causes the Q498R and N501Y substitutions present in Omicron to be more favorable in that background than in earlier viral strains. In contrast, the Omicron substitution Q493R exhibits no sign of entrenchment, with the derived state, R493, being as unfavorable for ACE2 binding in Omicron RBDs as in Wuhan-Hu-1. Likely for this reason, the R493Q reversion has occurred in Omicron sub-variants including BA.4/BA.5 and BA.2.75, where the affinity buffer from R493Q reversion may potentiate concurrent antigenic change. Consistent with prior studies, we find that Omicron RBDs have reduced expression, and identify candidate stabilizing mutations that ameliorate this deficit. Last, our maps highlight a broadening of the sites of escape from LY-CoV1404 antibody binding in BA.1 and BA.2 compared to the ancestral Wuhan-Hu-1 background. These BA.1 and BA.2 deep mutational scanning datasets identify shifts in the RBD mutational landscape and inform ongoing efforts in viral surveillance. |
| first_indexed | 2024-04-09T18:23:24Z |
| format | Article |
| id | doaj.art-935a02fbd2d6495d8f961be0fd3e02fe |
| institution | Directory Open Access Journal |
| issn | 1553-7366 1553-7374 |
| language | English |
| last_indexed | 2024-04-09T18:23:24Z |
| publishDate | 2022-11-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Pathogens |
| spelling | doaj.art-935a02fbd2d6495d8f961be0fd3e02fe2023-04-12T05:31:38ZengPublic Library of Science (PLoS)PLoS Pathogens1553-73661553-73742022-11-011811e101095110.1371/journal.ppat.1010951Deep mutational scans for ACE2 binding, RBD expression, and antibody escape in the SARS-CoV-2 Omicron BA.1 and BA.2 receptor-binding domains.Tyler N StarrAllison J GreaneyCameron M StewartAlexandra C WallsWilliam W HannonDavid VeeslerJesse D BloomSARS-CoV-2 continues to acquire mutations in the spike receptor-binding domain (RBD) that impact ACE2 receptor binding, folding stability, and antibody recognition. Deep mutational scanning prospectively characterizes the impacts of mutations on these biochemical properties, enabling rapid assessment of new mutations seen during viral surveillance. However, the effects of mutations can change as the virus evolves, requiring updated deep mutational scans. We determined the impacts of all single amino acid mutations in the Omicron BA.1 and BA.2 RBDs on ACE2-binding affinity, RBD folding, and escape from binding by the LY-CoV1404 (bebtelovimab) monoclonal antibody. The effects of some mutations in Omicron RBDs differ from those measured in the ancestral Wuhan-Hu-1 background. These epistatic shifts largely resemble those previously seen in the Alpha variant due to the convergent epistatically modifying N501Y substitution. However, Omicron variants show additional lineage-specific shifts, including examples of the epistatic phenomenon of entrenchment that causes the Q498R and N501Y substitutions present in Omicron to be more favorable in that background than in earlier viral strains. In contrast, the Omicron substitution Q493R exhibits no sign of entrenchment, with the derived state, R493, being as unfavorable for ACE2 binding in Omicron RBDs as in Wuhan-Hu-1. Likely for this reason, the R493Q reversion has occurred in Omicron sub-variants including BA.4/BA.5 and BA.2.75, where the affinity buffer from R493Q reversion may potentiate concurrent antigenic change. Consistent with prior studies, we find that Omicron RBDs have reduced expression, and identify candidate stabilizing mutations that ameliorate this deficit. Last, our maps highlight a broadening of the sites of escape from LY-CoV1404 antibody binding in BA.1 and BA.2 compared to the ancestral Wuhan-Hu-1 background. These BA.1 and BA.2 deep mutational scanning datasets identify shifts in the RBD mutational landscape and inform ongoing efforts in viral surveillance.https://doi.org/10.1371/journal.ppat.1010951 |
| spellingShingle | Tyler N Starr Allison J Greaney Cameron M Stewart Alexandra C Walls William W Hannon David Veesler Jesse D Bloom Deep mutational scans for ACE2 binding, RBD expression, and antibody escape in the SARS-CoV-2 Omicron BA.1 and BA.2 receptor-binding domains. PLoS Pathogens |
| title | Deep mutational scans for ACE2 binding, RBD expression, and antibody escape in the SARS-CoV-2 Omicron BA.1 and BA.2 receptor-binding domains. |
| title_full | Deep mutational scans for ACE2 binding, RBD expression, and antibody escape in the SARS-CoV-2 Omicron BA.1 and BA.2 receptor-binding domains. |
| title_fullStr | Deep mutational scans for ACE2 binding, RBD expression, and antibody escape in the SARS-CoV-2 Omicron BA.1 and BA.2 receptor-binding domains. |
| title_full_unstemmed | Deep mutational scans for ACE2 binding, RBD expression, and antibody escape in the SARS-CoV-2 Omicron BA.1 and BA.2 receptor-binding domains. |
| title_short | Deep mutational scans for ACE2 binding, RBD expression, and antibody escape in the SARS-CoV-2 Omicron BA.1 and BA.2 receptor-binding domains. |
| title_sort | deep mutational scans for ace2 binding rbd expression and antibody escape in the sars cov 2 omicron ba 1 and ba 2 receptor binding domains |
| url | https://doi.org/10.1371/journal.ppat.1010951 |
| work_keys_str_mv | AT tylernstarr deepmutationalscansforace2bindingrbdexpressionandantibodyescapeinthesarscov2omicronba1andba2receptorbindingdomains AT allisonjgreaney deepmutationalscansforace2bindingrbdexpressionandantibodyescapeinthesarscov2omicronba1andba2receptorbindingdomains AT cameronmstewart deepmutationalscansforace2bindingrbdexpressionandantibodyescapeinthesarscov2omicronba1andba2receptorbindingdomains AT alexandracwalls deepmutationalscansforace2bindingrbdexpressionandantibodyescapeinthesarscov2omicronba1andba2receptorbindingdomains AT williamwhannon deepmutationalscansforace2bindingrbdexpressionandantibodyescapeinthesarscov2omicronba1andba2receptorbindingdomains AT davidveesler deepmutationalscansforace2bindingrbdexpressionandantibodyescapeinthesarscov2omicronba1andba2receptorbindingdomains AT jessedbloom deepmutationalscansforace2bindingrbdexpressionandantibodyescapeinthesarscov2omicronba1andba2receptorbindingdomains |