%0 Journal Article %T Local structure of a peptide contact site on Ak alpha %+ Laboratoire de Biologie structurale %+ Sandoz Pharma Ltd. %A Wei, Bing-Yuan %A Gervois, Nadine %A Mer, Georges %A Adorini, Luciano %A Benoist, Christophe %A Mathis, Diane %< avec comité de lecture %@ 0953-8178 %J International Immunology %I Oxford University Press (OUP) %V 3 %N 8 %P 833-7 %8 1991-08 %D 1991 %R 10.1093/intimm/3.8.833 %M 1911551 %K MHC class II %K mutagenesis %K structure/function %K antigen presentation %Z Life Sciences [q-bio]Journal articles %X We have sought to determine how much amino acid diversity is tolerable at position 69 of the A* chain, a position previously implicated as a peptlde contact site. Slot-machine mutagenesis was used to create a set of 11 mutant A* cDNAs, each specifying a different amino acid at position 69. These cDNAs were individually expressed In L cells together with a wild-type AJj cDNA to produce a panel of mutant antigen-presenting cell lines. The ability of each member of this panel to present a hen egg lysozyme and a bovine ribonuciease peptlde to various T hybrldomas was assessed. We found that a surprising degree of amino acid diversity is tolerable at A* position 69: even charged (Glu, Arg) or bulky (Trp, Tyr) residues can be accommodated without abrogating cell-surface expression of A k , peptide binding to it, or T cell recognition of It. We discuss the Implications of these findings for models of T cell recognition of the class II molecule/antigen duplex. %G English %2 https://inserm.hal.science/inserm-03351859/document %2 https://inserm.hal.science/inserm-03351859/file/3-8-833.pdf %L inserm-03351859 %U https://inserm.hal.science/inserm-03351859 %~ INSERM