Crystal structure of human Ig-beta homodimer

Experimental Data Snapshot

  • Resolution: 3.20 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.181 

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Structural and Functional Studies of Igalphabeta and Its Assembly with the B Cell Antigen Receptor.

Radaev, S.Zou, Z.Tolar, P.Nguyen, K.Nguyen, A.Krueger, P.D.Stutzman, N.Pierce, S.Sun, P.D.

(2010) Structure 18: 934-943

  • DOI: https://doi.org/10.1016/j.str.2010.04.019
  • Primary Citation of Related Structures:  
    3KG5, 3KHO, 3KHQ

  • PubMed Abstract: 

    The B cell antigen receptor (BCR) plays an essential role in all phases of B cell development. Here we show that the extracellular domains of murine and human Igbeta form an I-set immunoglobulin-like structure with an interchain disulfide between cysteines on their G strands. Structural and sequence analysis suggests that Igalpha displays a similar fold as Igbeta. An Igalphabeta heterodimer model was generated based on the unique disulfide-bonded Igbeta dimer. Solution binding studies showed that the extracellular domains of Igalphabeta preferentially recognize the constant region of BCR with mu chain specificity, suggesting a role for Igalphabeta to enhance BCRmu chain signaling. Cluster mutations on Igalpha, Igbeta, and a membrane-bound form of immunoglobulin (mIgM) based on the structural model identified distinct areas of potential contacts involving charged residues on both subunits of the coreceptor and the Cmu4 domain of mIgM. These studies provide the first structural model for understanding BCR function.

  • Organizational Affiliation

    Structural Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, MD 20852, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
B-cell antigen receptor complex-associated protein beta chain
A, B
134Homo sapiensMutation(s): 0 
Gene Names: B29CD79BIGB
UniProt & NIH Common Fund Data Resources
Find proteins for P40259 (Homo sapiens)
Explore P40259 
Go to UniProtKB:  P40259
GTEx:  ENSG00000007312 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP40259
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.20 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.181 
  • Space Group: P 41 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 129.8α = 90
b = 129.8β = 90
c = 129.8γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-08-25
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance