3QXD: F54c Hla-dr1 Bound With Clip Peptide

Citation:
Abstract
HLA-DM is required for efficient peptide exchange on class II MHC molecules, but its mechanism of action is controversial. We trapped an intermediate state of class II MHC HLA-DR1 by substitution of alphaF54, resulting in a protein with increased HLA-DM binding affinity, weakened MHC-peptide hydrogen bonding as measured by hydrogen-deuterium exchange mass spectrometry, and increased susceptibility to DM-mediated peptide exchange. Structural analysis revealed a set of concerted conformational alterations at the N-terminal end of the peptide-binding site. These results suggest that interaction with HLA-DM is driven by a conformational change of the MHC II protein in the region of the alpha-subunit 3(10) helix and adjacent extended strand region, and provide a model for the mechanism of DM-mediated peptide exchange.
PDB ID: 3QXDDownload
MMDB ID: 95041
PDB Deposition Date: 2011/3/1
Updated in MMDB: 2011/12 
Experimental Method:
x-ray diffraction
Resolution: 2.3  Å
Source Organism:
Similar Structures:
Biological Unit for 3QXD: trimeric; determined by author and by software (PISA)
Molecular Components in 3QXD
Label Count Molecule
Proteins (3 molecules)
1
HLA Class II Histocompatibility Antigen, DR Alpha Chain
Molecule annotation
1
HLA Class II Histocompatibility Antigen, Drb1-1 Beta Chain
Molecule annotation
1
HLA Class II Histocompatibility Antigen Gamma Chain Peptide
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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