Fig. 1. Disulfide-stabilized HLA-A*02:01.

a Crystal structure of empty dsA2 (PDB 6TDR^14,68) seen as a top view of the peptide pocket. β₂m is shown in olive and the heavy chain in green. The stabilizing disulfide bond (positions 84 and 139 mutated to cysteines) is depicted in yellow. b dsA2 is refolded in presence of GM or GL dipeptide, which is then removed via size-exclusion chromatography. Afterward, full-length peptides can bind into the empty binding groove. Raw (c) and deconvoluted (d) native mass spectra of peptide-free dsA2 were recorded at an acceleration voltage of 25 V. The empty dsA2 is the predominant species (yellow). In addition, dsA2/erucamide (coral) and dissociated β₂m (olive) and heavy chain (green) can be seen.