Probing HLA-B7 conformational shifts induced by peptide-binding groove mutations and bound peptide with anti-HLA monoclonal antibodies
| Autor: | K D Smith, B E Mace, A Valenzuela, J L Vigna, J A McCutcheon, J A Barbosa, E Huczko, V H Engelhard, C T Lutz |
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| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | The Journal of Immunology. 157:2470-2478 |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.157.6.2470 |
| Popis: | To determine the influence of peptide-binding groove residues and MHC-bound peptide on HLA-B7 conformation, we investigated the binding sites of nine locus- or allele-specific mAbs using a panel of 82 HLA-B7 variants. The functional mAb epitopes encircle the HLA-B7 peptide-binding groove. Three mAbs are affected by mutations at solvent-accessible peptide-binding groove mutations. Mutations in peptide-binding groove residues 45, 63, and 150 affect multiple nonoverlapping mAb epitopes, probably by interaction with other MHC residues or bound peptide. However, 18 of 24 peptide-binding groove mutations do not affect mAb binding, indicating that the conformation of solvent-accessible HLA-B7 structures is largely dissociated from changes in the peptide-binding groove. To test whether bound peptides alter HLA-B7 conformation, we loaded HLA-B7 heavy chains on acid-stripped cells with beta2-microglobulin and 20 individual synthetic peptides. Two of eight mAbs are sensitive to HLA-B7-bound peptides. A likely interpretation of these data is that the conformational flexibility of HLA-B7 is due to peptide-induced conformational shifts in MHC side chains, rather than major shifts in the MHC main chain. These results suggest that HLA-B7 conformation is largely maintained in the context of different bound peptides and different peptide-binding grooves. |
| Databáze: | OpenAIRE |
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