3HLA

HUMAN CLASS I HISTOCOMPATIBILITY ANTIGEN A2.1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Work: 0.169 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Refined structure of the human histocompatibility antigen HLA-A2 at 2.6 A resolution.

Saper, M.A.Bjorkman, P.J.Wiley, D.C.

(1991) J.Mol.Biol. 219: 277-319


  • PubMed Abstract: 
  • The three-dimensional structure of the human histocompatibility antigen HLA-A2 was determined at 3.5 A resolution by a combination of isomorphous replacement and iterative real-space averaging of two crystal forms. The monoclinic crystal form has now ...

    The three-dimensional structure of the human histocompatibility antigen HLA-A2 was determined at 3.5 A resolution by a combination of isomorphous replacement and iterative real-space averaging of two crystal forms. The monoclinic crystal form has now been refined by least-squares methods to an R-factor of 0.169 for data from 6 to 2.6 A resolution. A superposition of the structurally similar domains found in the heterodimer, alpha 1 onto alpha 2 and alpha 3 onto beta 2m, as well as the latter pair onto the ancestrally related immunoglobulin constant domain, reveals that differences are mainly in the turn regions. Structural features of the alpha 1 and alpha 2 domains, such as conserved salt-bridges that contribute to stability, specific loops that form contacts with other domains, and the antigen-binding groove formed from two adjacent helical regions on top of an eight-stranded beta-sheet, are analyzed. The interfaces between the domains, especially those between beta 2m and the HLA heavy chain presumably involved in beta 2m exchange and heterodimer assembly, are described in detail. A detailed examination of the binding groove confirms that the solvent-accessible amino acid side-chains that are most polymorphic in mouse and human alleles fill up the central and widest portion of the binding groove, while conserved side-chains are clustered at the narrower ends of the groove. Six pockets or sub-sites in the antigen-binding groove, of diverse shape and composition, appear suited for binding side-chains from antigenic peptides. Three pockets contain predominantly non-polar atoms; but others, especially those at the extreme ends of the groove, have clusters of polar atoms in close proximity to the "extra" electron density in the binding site. A possible role for beta 2m in stabilizing permissible peptide complexes during folding and assembly is presented.


    Related Citations: 
    • Structure of the Human Class I Histocompatibility Antigen, Hla-A2
      Bjorkman, P.J.,Saper, M.A.,Samraoui, B.,Bennett, W.S.,Strominger, J.L.,Wiley, D.C.
      (1987) Nature 329: 506
    • Specificity Pockets for the Side Chains of Peptide Antigens in Hla-Aw68
      Garrett, T.P.J.,Saper, M.A.,Bjorkman, P.J.,Strominger, J.L.,Wiley, D.C.
      (1989) Nature 342: 692
    • The Foreign Antigen Binding Site and T Cell Recognition Regions of Class I Histocompatibility Antigens
      Bjorkman, P.J.,Saper, M.A.,Samraoui, B.,Bennett, W.S.,Strominger, J.L.,Wiley, D.C.
      (1987) Nature 329: 512
    • Crystallization and X-Ray Diffraction Studies on the Histocompatibility Antigens Hla-A2 and Hla-A28 from Human Cell Membranes
      Bjorkman, P.J.,Strominger, J.L.,Wiley, D.C.
      (1985) J.Mol.Biol. 186: 205


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CLASS I HISTOCOMPATIBILITY ANTIGEN (HLA-A2.1) (ALPHA CHAIN)
A
270Homo sapiensMutation(s): 0 
Gene Names: HLA-A (HLAA)
Find proteins for P01892 (Homo sapiens)
Go to Gene View: HLA-A
Go to UniProtKB:  P01892
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
BETA 2-MICROGLOBULIN
B
99Homo sapiensMutation(s): 0 
Gene Names: B2M
Find proteins for P61769 (Homo sapiens)
Go to Gene View: B2M
Go to UniProtKB:  P61769
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Work: 0.169 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 60.350α = 90.00
b = 80.400β = 120.42
c = 56.490γ = 90.00
Software Package:
Software NamePurpose
X-PLORrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1990-04-15
    Type: Initial release
  • Version 1.1: 2008-03-25
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance