Expression, purification and preliminary X-ray crystallographic analysis of the human major histocompatibility antigen HLA-B*1402 in complex with a viral peptide and with a self-peptide.

The product of the human major histocompatibility (HLA) class I allele HLA-B1402 only differs from that of allele HLA-B1403 at amino-acid position 156 of the heavy chain (Leu in HLA-B1402 and Arg in HLA-B1403). However, both subtypes are known to be differentially associated with the inflammatory rheumatic disease ankylosing spondylitis (AS) in black populations in Cameroon and Togo. HLA-B1402 is not associated with AS, in contrast to HLA-B1403, which is associated with this disease in the Togolese population. The products of these alleles can present peptides with Arg at position 2, a feature shared by a small group of other HLA-B antigens, including HLA-B2705, the prototypical AS-associated subtype. Complexes of HLA-B1402 with a viral peptide (RRRWRRLTV, termed pLMP2) and a self-peptide (IRAAPPPLF, termed pCatA) were prepared and were crystallized using polyethylene glycol as precipitant. The complexes crystallized in space groups P2(1) (pLMP2) and P2(1)2(1)2(1) (pCatA) and diffracted synchrotron radiation to 2.55 and 1.86 A resolution, respectively. Unambiguous solutions for both data sets were obtained by molecular replacement using a peptide-complexed HLA-B*2705 molecule (PDB code 1jge) as a search model.