The tumor-associated gp100 epitope was embedded in the MHC I heavy chain in the canonical mode for 9mer peptides, and the quality of the EM map at a local resolution of 2.6 Å allowed unambiguous placement of all residues of the tumor-associated antigen, re-emphasizing the important role of Val9 in anchoring the heteroclitic YLEPGPVTV peptide in the MHC I α1α2 groove (Figures 2A and 2B; Figure S3; Bianchi et al., 2016). Here, PMEL is linked to neoplasm.