1ZHB: Crystal Structure Of The Murine Class I Major Histocompatibility Complex Of H-2Db, B2-Microglobulin, and a 9-Residue Peptide Derived from rat dopamine beta-monooxigenase

Molecular mimicry of self-epitopes by viral antigens is one possible pathogenic mechanism underlying induction of autoimmunity. A self-epitope, mDBM, derived from mouse dopamine beta-mono-oxygenase (KALYDYAPI) sharing 44% sequence identity with the lymphocytic choriomeningitis virus-derived immunodominant epitope gp33 (KAVYNFATC/M), has previously been identified as a cross-reactive self-ligand, presentation of which results in autoimmunity. A rat peptide homologue, rDBM (KALYNYAPI, 56% identity to gp33), which displayed similar properties to mDBM, has also been identified. We herein report the crystal structure of H-2Db.rDBM and a comparison with the crystal structures of the cross-reactive H-2Db.gp33 and non-cross-reactive H-2Db.gp33 (V3L) escape variant (KALYNFATM, 88% identity to gp33). Despite the large sequence disparity, rDBM and gp33 peptides are presented in nearly identical manners by H-2Db, with a striking juxtaposition of the central sections of both peptides from residues p3 to p7. The structural similarity provides H-2Db in complex with either a virus-derived or a dopamine beta-mono-oxygenase-derived peptide with a shared antigenic identity that conserves the positioning of the heavy chain and peptide residues that interact with the T cell receptor (TCR). This stands in contrast to the structure of H-2Db.gp33 (V3L), in which a single conserved mutation, also present in rDBM, induces large movements of both the peptide backbone and the side chains that interact with the TCR. The TCR-interacting surfaces of the H-2Db.rDBM and H-2Db.gp33 major histocompatibility complexes are very similar with regard to shape, topology, and charge distribution, providing a structural basis for CD8 T cell activation by molecular mimicry and potential subsequent development of autoreactivity.
PDB ID: 1ZHBDownload
MMDB ID: 33854
PDB Deposition Date: 2005/4/25
Updated in MMDB: 2017/12
Experimental Method:
x-ray diffraction
Resolution: 2.7  Å
Source Organism:
Mus musculus
Similar Structures:
Biological Unit for 1ZHB: trimeric; determined by author and by software (PISA)
Molecular Components in 1ZHB
Label Count Molecule
Proteins (3 molecules)
H-2 Class I Histocompatibility Antigen, D-B Alpha Chain(Gene symbol: H2-D1)
Molecule annotation
Molecule annotation
9-mer Peptide From Dopamine Beta-monooxygenase(Gene symbol: Dbh)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB