Wj. Metzler et al., SOLUTION STRUCTURE OF HUMAN CTLA-4 AND DELINEATION OF A CD80 CD86 BINDING-SITE CONSERVED IN CD28/, Nature structural biology, 4(7), 1997, pp. 527-531
The structure of human CTLA-4 reveals that residues Met 99, Tyr 100 an
d Tyr 104 of the M99YPPPY104 motif are adjacent to a patch of charged
surface residues on the A'GFCC' face of the protein. Mutation of these
residues, which are conserved in the CTLA-4/CD28 family, significantl
y reduces binding to CD80 and/or CD86, implicating this patch as a lig
and binding site.