Role of strong anchor residues in the effective binding of 10-mer and 11-mer peptides to HLA-A*2402 molecules.
The binding capacity of one-hundred-and-seventy-two 8-mer to 11-mer peptides carrying HLA-A24 anchor residues to HLA-A*2402 molecules was analyzed by using a HLA class I stabilization assay. Most (76. 2%) of these peptides bound to HLA-A*2402 molecules. These results confirmed previous findings that Tyr and Phe at P2 as well as Phe, Trp, Ile, and Leu at the C-terminus were main anchor residues for HLA-A*2402. Tyr at P2 was a stronger anchor residue than Phe, while bulky aromatic hydrophobic residues Phe and Trp at the C-terminus are stronger anchors than aliphatic hydrophobic residues Ile and Leu. These results were also supported by an analysis using a panel of mutated 9-mer peptides at P2 and P9. Taken together, these results suggest that HLA-A*2402 molecules have deep B- and F-pockets because they favor peptides carrying bulky aromatic hydrophobic residues at P2 and the C-terminus. The affinity of 8-mer peptides was significantly lower than that of 9-mer to 11-mer peptides, while there was no difference in affinity between 9-mer, 10-mer, and 11-mer peptides. The affinity of peptides carrying bulky aromatic hydrophobic residues at the C-terminus was higher than that of peptides carrying aliphatic hydrophobic residues in each of the 8-mer to 11-mer peptides, though the greatest difference in affinity was observed in 11-mer peptides. The strong interaction of side chains of these anchor residues with the corresponding pockets may permit the effective binding of 10-mer and 11-mer peptides to HLA-A*2402 molecules.
Ibe
M
M
Department of Tumor Biology, Institute of Medical Science, University of Tokyo, Shirokanedai 4-6-1, Minato-ku, Tokyo 108, Japan.
Moore
Y I
YI
Miwa
K
K
Kaneko
Y
Y
Yokota
S
S
Takiguchi
M
M
D001665:Binding Sites; D005434:Flow Cytometry; D015234:HLA-A Antigens / Q000378:metabolism*; D059871:HLA-A24 Antigen; D006801:Humans; D007532:Isoleucine / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D010649:Phenylalanine / Q000378:metabolism; D013329:Structure-Activity Relationship; D014443:Tyrosine / Q000378:metabolism
D015234:HLA-A Antigens; D059871:HLA-A24 Antigen; D010455:Peptides; D007532:Isoleucine; D014443:Tyrosine; D010649:Phenylalanine; D007930:Leucine