7Y6K image
Entry Detail
PDB ID:
7Y6K
EMDB ID:
Title:
Cryo-EM structure of SARS-CoV-2 receptor binding domain in complex with K202.B bispecific antibody
Biological Source:
PDB Version:
Deposition Date:
2022-06-20
Release Date:
2023-07-19
Method Details:
Experimental Method:
Resolution:
3.34 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Spike glycoprotein
Mutations:R682G, R683S, R685S, F817P, A892P, A899P, A942P, K986P, V987P
Chain IDs:A (auth: B)
Chain Length:1208
Number of Molecules:1
Biological Source:Severe acute respiratory syndrome coronavirus 2
Polymer Type:polypeptide(L)
Description:scFv region of light chain from K202.B, bispecific antibody
Chain IDs:B (auth: E)
Chain Length:478
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Fab region of light chain from K202.B, bispecific antibody
Chain IDs:C (auth: I)
Chain Length:478
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Fab region of heavy chain from K202.B, bispecific antibody
Chain IDs:D (auth: J)
Chain Length:454
Number of Molecules:1
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Novel bispecific human antibody platform specifically targeting a fully open spike conformation potently neutralizes multiple SARS-CoV-2 variants.
Antiviral Res. 212 105576 105576 (2023)
PMID: 36870394 DOI: 10.1016/j.antiviral.2023.105576

Abstact

Rapid emergence of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has prompted an urgent need for the development of broadly applicable and potently neutralizing antibody platform against the SARS-CoV-2, which can be used for combatting the coronavirus disease 2019 (COVID-19). In this study, based on a noncompeting pair of phage display-derived human monoclonal antibodies (mAbs) specific to the receptor-binding domain (RBD) of SARS-CoV-2 isolated from human synthetic antibody library, we generated K202.B, a novel engineered bispecific antibody with an immunoglobulin G4-single-chain variable fragment design, with sub- or low nanomolar antigen-binding avidity. Compared with the parental mAbs or mAb cocktail, the K202.B antibody showed superior neutralizing potential against a variety of SARS-CoV-2 variants in vitro. Furthermore, structural analysis of bispecific antibody-antigen complexes using cryo-electron microscopy revealed the mode of action of K202.B complexed with a fully open three-RBD-up conformation of SARS-CoV-2 trimeric spike proteins by simultaneously interconnecting two independent epitopes of the SARS-CoV-2 RBD via inter-protomer interactions. Intravenous monotherapy using K202.B exhibited potent neutralizing activity in SARS-CoV-2 wild-type- and B.1.617.2 variant-infected mouse models, without significant toxicity in vivo. The results indicate that this novel approach of development of immunoglobulin G4-based bispecific antibody from an established human recombinant antibody library is likely to be an effective strategy for the rapid development of bispecific antibodies, and timely management against fast-evolving SARS-CoV-2 variants.

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