1i3r
CRYSTAL STRUCTURE OF A MUTANT IEK CLASS II MHC MOLECULE
OverviewOverview
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.
About this StructureAbout this Structure
1I3R is a Protein complex structure of sequences from Mus musculus. Full crystallographic information is available from OCA.
ReferenceReference
Mutations changing the kinetics of class II MHC peptide exchange., Wilson N, Fremont D, Marrack P, Kappler J, Immunity. 2001 May;14(5):513-22. PMID:11371354 Page seeded by OCA on Fri May 2 19:32:15 2008