“…In addition, and as for pocket A, the last pocket also closes the C-terminal end of the cleft, with large aromatic residues at position 80, 81, 84, 123, 143 (as observed in HLA-A*02:01). The Tyr84 is conserved in about a third of HLA-I molecules [ 4 ], and replaced by Phe84 in ∼10% of HLA-I, and can be used as a switch that opens to enable the binding of longer peptides [ 14 , 15 ]. Interestingly, a large bulky residue at position 84 is also observed in lipid and metabolite antigen binding MHC-like molecules CD1 and MR1, respectively.…”