We discuss here the problems in identifying sequence motifs of peptides that bind to I-Ag7, the class II histocompatibility molecule of NOD diabetic mice. We present studies that indicate a minor contribution of amino acid side chains for binding. A peptide from the Eα chain binds to I-Ag7 molecules and is recognized by CD4 T cells. By producing single-residue mutations we identified four residues that were considered to contact the T cell receptor. No residue was found to be essential for binding to I-Ag7: a peptide that contained the T cell contact residues, on a backbone of alanines, bound to I-Ag7 and stimulated the T cells. We conclude that peptides can bind to I-Ag7 without the requirement for residues with prominent side chains to anchor them.
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jul 20 1999|