2mha
CRYSTAL STRUCTURE OF THE MAJOR HISTOCOMPATIBILITY COMPLEX CLASS I H-2KB MOLECULE CONTAINING A SINGLE VIRAL PEPTIDE: IMPLICATIONS FOR PEPTIDE BINDING AND T-CELL RECEPTOR RECOGNITION
Structural highlights
FunctionHA1B_MOUSE Involved in the presentation of foreign antigens to the immune system. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedTo study the structure of a homogenous major histocompatibility complex (MHC) class I molecule containing a single bound peptide, a complex of recombinant mouse H-2Kb, beta 2-microglobulin (beta 2m), and a fragment of the vesicular stomatitis virus (VSV) nuclear capsid protein, VSV-(N52-59) octapeptide (Arg-Gly-Tyr-Val-Tyr-Gln-Gly-Leu), was prepared by exploiting a high-yield bacterial expression system and in vitro cocomplex formation. The structure of mouse H-2Kb revealed its similarity to three human class I HLA molecules, consistent with the high primary sequence homology and common function of these peptide-presenting molecules. Electron density was located in the peptide-binding groove, to which a single peptide in a unique conformation was unambiguously fit. The peptide extends the length of the groove, parallel to the alpha-helices, and assumes an extended, mostly beta-strand conformation. The peptide is constrained within the groove by hydrogen bonding of its main-chain atoms and by contacts of its side chains with the H-2Kb molecule. The amino-terminal nitrogen atom of the peptide forms a hydrogen bond with the hydroxyl group of Tyr-171 of H-2Kb at one end of the groove, while the carboxyl-terminal oxygen forms a hydrogen bond with the hydroxyl group of Tyr-84 at the other end. Since the amino acids at both ends are conserved among human and mouse MHC molecules, this anchoring of each end of the peptide appears to be a general feature of peptide-MHC class I molecule binding and imposes restrictions on its length. The side chains of residues Tyr-3, Tyr-5, and Leu-8 of the VSV octapeptide fit into the interior of the H-2Kb molecule with no appreciable surface exposure, a finding in support of previous biological studies that showed the importance of these residues for binding. Thus, the basis for binding of specific peptide sequences to the MHC class I molecule is the steric restriction imposed on the peptide side chains by the architecture of the floor and sides of the groove. The side chains of Arg-1, Val-4, and Gln-6 and the main-chain of Gly-7 of the octapeptide are exposed on the surface of the complex, thus confirming their availability for T-cell receptor contact, as previously demonstrated by T-cell recognition experiments. Crystal structure of the major histocompatibility complex class I H-2Kb molecule containing a single viral peptide: implications for peptide binding and T-cell receptor recognition.,Zhang W, Young AC, Imarai M, Nathenson SG, Sacchettini JC Proc Natl Acad Sci U S A. 1992 Sep 1;89(17):8403-7. PMID:1325657[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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