2fwo
MHC Class I H-2Kd heavy chain in complex with beta-2microglobulin and peptide derived from influenza nucleoprotein
Structural highlights
FunctionHA1D_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 PubMedClassic major histocompatibility complex (MHC) proteins associate with antigen- and self-derived peptides in an allele-specific manner. Herein we present the crystal structure of the MHC class I protein H-2K(d) (K(d)) expressed by BALB/c mice in complex with an antigenic peptide derived from influenza A/PR/8/34 nucleoprotein (Flu, residues 147-155, TYQRTRALV). Analysis of our structure in conjunction with the sequences of naturally processed epitopes provides a comprehensive understanding of the dominant K(d) peptide-binding motif. We find that Flu residues Tyr(P2), Thr(P5), and Val(P9) are sequestered into the B, C, and F pockets of the K(d) groove, respectively. The shape and chemistry of the polymorphic B pocket make it an optimal binding site for the side chain of Tyr(P2) as the dominant anchoring residue of nonameric peptides. The non-polar F pocket limits the amino acid repertoire at P9 to hydrophobic residues such as Ile, Leu, or Val, whereas the C pocket restricts the size of the P5-anchoring side chain. We also show that Flu is accommodated in the complex through an unfavorable kink in the otherwise extended peptide backbone due to the presence of a prominent ridge in the K(d) groove. Surprisingly, this backbone conformation is strikingly similar to D(b)-presented peptides despite the fact that these proteins employ distinct motif-anchoring strategies. The results presented in this study provide a solid foundation for the understanding of K(d)-restricted antigen presentation and recognition events. Structural definition of the H-2Kd peptide-binding motif.,Mitaksov V, Fremont DH J Biol Chem. 2006 Apr 14;281(15):10618-25. Epub 2006 Feb 10. PMID:16473882[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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