9U9B
HBsAg in complex with HBC34 Fab
Summary for 9U9B
| Entry DOI | 10.2210/pdb9u9b/pdb |
| EMDB information | 63960 |
| Descriptor | Middle S protein, HBC34 Fab Heavy Chain, HBC34 Fab Light Chain (3 entities in total) |
| Functional Keywords | hbv, hbsag, fab, antigenic loop, viral protein, viral protein-immune system complex, viral protein/immune system |
| Biological source | Hepatitis B virus More |
| Total number of polymer chains | 4 |
| Total formula weight | 108820.44 |
| Authors | |
| Primary citation | He, X.,Tao, W.,Kang, Y.,Xu, J.,Liu, X.,Chen, L. Structural polymorphism of the antigenic loop in HBV surface antigen dictates binding of diverse neutralizing antibodies. Cell Discov, 11:57-57, 2025 Cited by PubMed Abstract: The Hepatitis B Virus (HBV) poses a significant health threat, causing millions of deaths each year. Hepatitis B surface antigen (HBsAg), the sole membrane protein on the HBV viral envelope, plays crucial roles in viral attachment to host cells and serves as the target for neutralizing antibodies (NAbs). Despite its functional and therapeutic significance, the mechanisms by which NAbs recognize HBsAg remain elusive. Here, we found that HBsAg proteins exist in distinct subtypes and are recognized by different groups of antibodies. Cryo-electron microscopy (Cryo-EM) structures of HBsAg dimers in complex with NAb Fab fragments reveal that the antigenic loop (AGL) of these distinct HBsAg types share a common structural core comprised of four β-strands. However, their surface structures exhibit unexpected polymorphism due to distinct disulfide bond linkages within the AGL region. This structural polymorphism determines the recognition of HBsAg by different groups of NAbs. PubMed: 40523894DOI: 10.1038/s41421-025-00803-2 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.25 Å) |
Structure validation
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