THE 3-DIMENSIONAL STRUCTURE OF H-2D(B) AT 2.4 ANGSTROM RESOLUTION - IMPLICATIONS FOR ANTIGEN-DETERMINANT SELECTION

Solution at 2.4 angstrom resolution of the structure of H-2D(b) with t he influenza virus peptide NP366-374 (ASNENMETM) and comparison with t he H-2K(b)-VSV (RGYVYQGL) structure allow description of the molecular details of MHC class I peptide binding interactions for mice of the H -2b haplotype, revealing a strategy that maximizes the repertoire of p eptides that can be presented. The H-2D(b) cleft has a mouse-specific hydrophobic ridge that causes a compensatory arch in the backbone of t he peptide, exposing the arch residues to TCR contact and requiring th e peptide to be at least 9 residues. This ridge occurs in about 40% of the known murine D and L allelic molecules, classifying them as a str uctural subgroup.