CRYSTALLIZATION AND PRELIMINARY-X-RAY ANALYSIS OF THE RECEPTOR-BINDING DOMAIN OF HUMAN AND BOVINE ALPHA(2)-MACROGLOBULIN

The receptor-binding domains (RBDs) of human and bovine alpha(2)-macro globulin (alpha(2)M) have been isolated after limited proteolysis of m ethylamine-treated alpha(2)M with papain. Single crystals of the RBDs have been grown by vapour diffusion. Crystals of human RED are very th in plates unsuited for data collection. However, crystals of RED from bovine alpha(2)M give diffraction patterns suitable for X-ray analysis , and a complete dataset with a maximum resolution of 2.3 Angstrom has been collected with synchrotron radiation at cryogenic temperature, T he crystals belong to spacegroup P3(1)21 or P3(2)21 with cell paramete rs a = b = 106.8 Angstrom, c = 72.2 Angstrom.