7XQ8

Structure of human B-cell antigen receptor of the IgM isotype

Summary for 7XQ8

• Entry DOI: 10.2210/pdb7xq8/pdb
• EMDB information: 33390
• Descriptor: Chimera of Heavy chain of VRC01 antibody Fab and Isoform 2 of Immunoglobulin heavy constant mu, Light chain of Fab fragments of the VRC01 antibody,Immunoglobulin kappa constant, B-cell antigen receptor complex-associated protein alpha chain, ... (5 entities in total)
• Functional Keywords: immunology, b cell signalling, adaptive immunity, antibody, signaling protein
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 6
• Total formula weight: 250896.26

Authors

Chen, M.Y.,Su, Q.,Shi, Y.G. (deposition date: 2022-05-07, release date: 2022-08-17, Last modification date: 2024-10-30)

Primary citation

Su, Q.,Chen, M.,Shi, Y.,Zhang, X.,Huang, G.,Huang, B.,Liu, D.,Liu, Z.,Shi, Y.
Cryo-EM structure of the human IgM B cell receptor.
Science, 377:875-880, 2022

PubMed Abstract: The B cell receptor (BCR) initiates immune responses through antigen recognition. We report a 3.3-angstrom cryo-electron microscopy structure of human immunoglobulin M (IgM)-BCR in the resting state. IgM-BCR comprises two heavy chains, two light chains, and the Igα/Igβ heterodimer. The ectodomains of the heavy chains closely stack against those of Igα/Igβ, with one heavy chain locked between Igα and Igβ in the juxtamembrane region. Extracellular interactions may determine isotype specificity of the BCR. The transmembrane helices of IgM-BCR form a four-helix bundle that appears to be conserved among all BCR isotypes. This structure contains 14 glycosylation sites on the IgM-BCR ectodomains and reveals three potential surface binding sites. Our work reveals the organizational principles of the BCR and may facilitate the design of antibody-based therapeutics.

PubMed: 35981043
DOI: 10.1126/science.abo3923

Experimental method

ELECTRON MICROSCOPY (3.3 Å)