Molecular analysis of TCR and peptide/MHC interaction using P18-I10-derived peptides with a single D-amino acid substitution.
For the structural analysis of T-cell receptor (TCR) and peptide/MHC interaction, a series of peptides with a single amino acid substitution by a corresponding D-amino acid, having the same weight, size, and charge, within P18-I10 (aa318-327: RGPGRAFVTI), an immunodominant epitope of HIV-1 IIIB envelope glycoprotein, restricted by the H-2Dd class I MHC molecule, has been synthesized. Using those peptides, we have observed that the replacement at positions 324F, 325V, 326T, and 327I with each corresponding D-amino acid induced marked reduction of the potency to sensitize targets for P18-I10-specific murine CD8+ cytotoxic T lymphocytes (CTLs), LINE-IIIB, recognition. To analyze further the role of amino acid at position 325, the most critical site for determining epitope specificity, we have developed a CTL line [LINE-IIIB(325D)] and its offspring clones specific for the epitope I-10(325v) having a D-valine (v) at position 325. Taking advantage of two distinct sets of CD8+ CTLs restricted by the same Dd, three-dimensional structural analysis on TCR and peptide/MHC complexes by molecular modeling was performed, which indicates that the critical amino acids within the TCRs for interacting with 325V or 325v appear to belong to the complementarity-determining region 1 but not to the complementarity-determining region 3 of Vbeta chain.
Nakagawa
Yohko
Y
Department of Microbiology and Immunology, Nippon Medical School, Tokyo 113-8602, Japan.
Kikuchi
Hiroto
H
Takahashi
Hidemi
H
D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D003198:Computer Simulation; D005260:Female; D005347:Fibroblasts / Q000737:chemistry / Q000378:metabolism; D015699:HIV Envelope Protein gp120 / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D006680:HLA Antigens / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D008956:Models, Chemical; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D011485:Protein Binding; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D013329:Structure-Activity Relationship
D015699:HIV Envelope Protein gp120; D006680:HLA Antigens; C483883:P18-I10 peptide; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell