2HLA: SPECIFICITY POCKETS FOR THE SIDE CHAINS OF PEPTIDE ANTIGENS IN HLA-AW68

Citation:
Abstract
We have determined the structure of a second human histocompatibility glycoprotein, HLA-Aw68, by X-ray crystallography and refined it to a resolution of 2.6 A. Overall, the structure is extremely similar to that of HLA-A2 (refs 1, 2; and M.A.S. et al., manuscript in preparation), although the 11 amino-acid substitutions at polymorphic residues in the antigen-binding cleft alter the detailed shape and electrostatic charge of that site. A prominent negatively charged pocket within the cleft extends underneath the alpha-helix of the alpha 1-domain, providing a potential subsite for recognizing a positively charged side chain or peptide N terminus. Uninterpreted electron density, presumably representing an unknown 'antigen(s)', which seems to be different from that seen in the HLA-A2 structure, occupies the cleft and extends into the negatively charged pocket in HLA-Aw68. The structures of HLA-Aw68 and HLA-A2 demonstrate how polymorphism creates and alters subsites (pockets) positioned to bind peptide side chains, thereby suggesting the structural basis for allelic specificity in foreign antigen binding.
PDB ID: 2HLADownload
MMDB ID: 2717
PDB Deposition Date: 1989/10/5
Updated in MMDB: 2017/12
Experimental Method:
x-ray diffraction
Resolution: 2.6  Å
Source Organism:
Similar Structures:
Biological Unit for 2HLA: dimeric; determined by author and by software (PISA)
Molecular Components in 2HLA
Label Count Molecule
Proteins (2 molecules)
1
Class I Histocompatibility Antigen (Hla-aw68)(Gene symbol: HLA-A)
Molecule annotation
1
Beta 2-microglobulin(Gene symbol: B2M)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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