Complex assembly, crystallization and preliminary X‐ray crystallographic studies of MHC H‐2K d complexed with an HBV‐core nonapeptide

In order to establish a system for structural studies of the murine class I major histocompatibility antigen complex (MHC) H‐2K d , a bacterial expression system and in vitro refolding preparation of the complex of H‐2K d with human β 2 m and the immunodominant peptide SYVNTNMGL from hepatitis B virus (HBV) core‐protein residues 87–95 was employed. The complex (45 kDa) was crystallized; the crystals belong to space group P 222 1 , with unit‐cell parameters a = 89.082, b = 110.398, c = 47.015 Å, α = β = γ = 90°. The crystals contain one complex per asymmetric unit and diffract X‐rays to at least 2.06 Å resolution. The structure has been solved by molecular replacement and is the first crystal structure of a peptide–H‐2K d complex.