Crystallization and preliminary crystallographic studies on the large extracellular domain of human CD81, a tetraspanin receptor for hepatitis C virus

The large extracellular domain of CD81, a member of the tetraspanin family and a receptor protein for hepatitis C virus envelope E2 glycoprotein, has been expressed, purified and subsequently crystallized using the sitting-dr op vapour-diffusion technique. Native diffraction data to 1.6 Angstrom reso lution were obtained at the ID14 beamline of the European Synchrotron Radia tion Facility from a flash-frozen crystal at 100 K. The crystals belong to space group P2(1), with unit-cell parameters a = 31.5, b = 77.2, c = 38.5 A ngstrom, beta = 107.4 degrees, and are likely to contain two extracellular domains (2 x 99 residues) per asymmetric unit.