CRYSTALLIZATION AND PRELIMINARY DIFFRACTION STUDIES OF THE EXTRACELLULAR REGION OF HUMAN P58 KILLER-CELL INHIBITORY RECEPTOR (KIR2)

Molecules of the human killer cell inhibitory receptor (KIR) family, w hich belong to the immunoglobulin superfamily (IgSF), are expressed on the surface of natural killer (NK) cells and some subsets of T cells. These receptors function to mediate the inhibition or activation of c ytotoxic activity by recognizing HLA class I molecules on the target c ell. The extracellular region of a p58 KIR's specific for HLA-Cw1,3,7 (KIR2) has been overproduced in Escherichia coli and purified. The rec ombinant KIR2 has been crystallized in 9-10% poly(ethylene glycol) met hyl ether (average M-r= 8000), 50mM HEPES, 8% ethylene glycol, 0.5% oc tyl-beta-glucoside, pH 7.5, at 294 K using the sitting-drop vapour-dif fusion method. Preliminary X-ray diffraction studies reveal the space group to be hexagonal (P6(1)22 or P6(5)22) with lattice constants a = b = 95.3, c = 130.8 Angstrom. A native data set (3 Angstrom resolution ) has been collected at the Photon Factory (lambda = 1.0 Angstrom).