Crystallization and preliminary X-ray analysis of the low-affinity complex between human leukocyte antigen-G (HLA-G) and leukocyte Ig-like receptor B2 (LILRB2).
Human leukocyte antigen-G (HLA-G) is a nonclassical MHC class I (MHCI) molecule that is expressed mainly on placenta trophoblast cells. Leukocyte Ig-like receptor B2 (LILRB2) is a human inhibitory immune receptor that recognizes HLA-G with a higher affinity than any other MHCI although this interaction is only in the microM range. The interaction between HLA-G and LILRB2 seems to play a dominant role in the escape of the fetus from the maternal immune response. Here we report the crystallization and x-ray analysis of the LILRB2/HLA-G complex. The extracellular domains of HLA-G and LILRB2 were expressed in Escherichia coli, refolded and purified. The initial crystallization trials using novel PEG-based screening sets provided crystals of the LILRB2/HLA-G complex with 40-50% PEG400 as the precipitant. These crystals belong to space group P3(1)21 (a=b=81.4 A, c=186.7 A, gamma=120 degrees ). Dehydration of the crystals by soaking them in a solution containing a higher concentration of PEG400 dramatically improved the resolution and also the mosaicity.
Shiroishi
Mitsunori
M
Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Maenaka
Katsumi
K
D003460:Crystallization; D018360:Crystallography, X-Ray; D006680:HLA Antigens / Q000737:chemistry* / Q000378:metabolism; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000378:metabolism; D011971:Receptors, Immunologic / Q000737:chemistry* / Q000378:metabolism
D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I; C491341:LILRB2 protein, human; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic