Preparation and crystallization of the disulfide-linked HLA-G dimer.
HLA-G is a non-classical MHC class I, which binds to inhibitory receptors, such as Leukocyte Ig-like receptors, to induce a wide range of tolerogenic immunological effects. HLA-G can be expressed as a disulfide-liked dimer both in solution and at the cell surface. However, the three-dimensional structure of the HLA-G dimer is unknown. Here, we report the crystallization of the disulfide-linked dimer form of HLA-G by adding dithiothreitol (DTT), enabling a 3.2-A data set to be collected. We also show that DTT promotes disulfide bond exchange of refolded HLA-G, whose free cysteine was protected, thus facilitating its dimerization. This technique could also be applied for disulfide-mediated dimer/multimer formation of refolded proteins harbouring free cysteines.
Shiroishi
Mitsunori
M
Division of Structural Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan.
Kohda
Daisuke
D
Maenaka
Katsumi
K
D003460:Crystallization; D019281:Dimerization; D004220:Disulfides / Q000737:chemistry*; D004229:Dithiothreitol; D006680:HLA Antigens / Q000737:chemistry* / Q000302:isolation & purification*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000737:chemistry* / Q000302:isolation & purification*; D006801:Humans
D004220:Disulfides; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I; D004229:Dithiothreitol