The composition of the F pocket in HLA-A*74 generates C-terminal promiscuity among its bound peptides

In this study we sequenced the bound peptides from three alleles belonging to the HLA-A*74 group (HLA-A*74:04, A*74:06 and A*74:07) that are distinguished by four polymorphic residues within the peptide-binding region. Our data illustrates that A*74:04 exhibits preference for L, M or I at P2 and L, S or P at P Omega, while for A*74:07 the P2 anchor prefers L, P or I and the P Omega anchor S, P, L. In contrast A*74:06 features a P2 anchor motif of S or L, while a P Omega anchor could not be defined; however, a preference for polar residues S, T, Q or the charged residue R at the P Omega position could be detected.