1I3R

CRYSTAL STRUCTURE OF A MUTANT IEK CLASS II MHC MOLECULE

Summary for 1I3R

• Entry DOI: 10.2210/pdb1i3r/pdb
• Related: 1IEA 1IEB
• Descriptor: H-2 CLASS II HISTOCOMPATIBILITY ANTIGEN, E-K ALPHA CHAIN, FUSION PROTEIN CONSISTING OF MHC E-BETA-K PRECURSOR, GLYCINE RICH LINKER, AND HEMOGLOBIN BETA-2 CHAIN, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (5 entities in total)
• Functional Keywords: mhc classii, immune system
• Biological source: Mus musculus (house mouse); More
• Cellular location: Membrane ; Single-pass type I membrane protein : P04224
• Total number of polymer chains: 8
• Total formula weight: 196474.92

Authors

Kappler, J.W.,Wilson, N. (deposition date: 2001-02-15, release date: 2001-06-20, Last modification date: 2024-10-30)

Primary citation

Wilson, N.,Fremont, D.,Marrack, P.,Kappler, J.
Mutations changing the kinetics of class II MHC peptide exchange.
Immunity, 14:513-522, 2001

PubMed Abstract: IE/DR MHC class II molecules have an extensive H-bonding network under the bound peptide. In IE(k), two alpha chain acidic amino acids in the core of this network were mutated to amides. At low pH, the mutant molecule exchanged peptide much more rapidly than the wild-type. The crystal structure of the mutant IE(k) revealed the loss of a single buried water molecule and a reorganization of the predicted H-bonding network. We suggest that these mutations enhance the transition of MHC class II to an open conformation at low pH allowing the bound peptide to escape. In wild-type IE(k), the need to protonate these amino acids also may be a bottleneck in the return to a closed conformation after peptide binding.

PubMed: 11371354
DOI: 10.1016/S1074-7613(01)00140-6

Experimental method

X-RAY DIFFRACTION (2.4 Å)