The N-terminal six residues of peptide core sequences suffice for binding to HLA-DR4 (DRB1*0405) and DR9 (DRB1*0901) molecules.
When examining anchor residues of a peptide 0405BP2 (1SPGTGAYYVLLN12) that was eluted from purified HLA-DR4 molecules (DRA/DRB1*0405), we found that heptamer peptides K7YYVLLN12 and K7YAALAN12 could bind to DR4 with the same affinity as 0405BP2, where artificially added Lys increases the solubility of peptides, and 7Y, 10L and 12N function as major anchor residues. In contrast, none of K8YVLLN12, K8AALAN12, K7YYVLL11 and K7YAALA11 had any detectable binding. Similar results were obtained with peptide K1WAASAAAAA9 that binds to DR9 (DRA/DRB1*0901) where 1W and 4S function as major anchor residues; K1WAASAA6, but not K1WAASA5 or K2AASAAAAA9 did bind to DR9 molecules. These data indicate that, when the most N-terminal anchor is designated as P1 (position 1), P1-6 but not P7-9 is essential, for binding at least to HLA-DR4 and DR9 molecules.
Matsushita
S
S
Department of Neuroscience and Immunology, Kumamoto University Graduate School of Medical Sciences, Honjo, Japan.
Fujisao
S
S
Nishimura
Y
Y
D000595:Amino Acid Sequence; D001667:Binding, Competitive; D002461:Cell Line, Transformed; D006684:HLA-DR Antigens / Q000378:metabolism*; D059810:HLA-DR Serological Subtypes; D015804:HLA-DR4 Antigen / Q000378:metabolism*; D006801:Humans; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D013379:Substrate Specificity
D006684:HLA-DR Antigens; D059810:HLA-DR Serological Subtypes; D015804:HLA-DR4 Antigen; C038988:HLA-DR9 antigen; D010446:Peptide Fragments