Crystallization of the lectin IV of Griffonia simplicifolia and its complexes with the Lewis b and Y human blood group determinants.

Single crystals of the lectin IV from Griffonia simplicifolia have been grown in the tetragonal crystal system. The space group is P4(2)2(1)2 with a = 78.95(5) A and c = 89.01(2) A, and there is one subunit of the dimeric glycoprotein in the crystallographic asymmetric unit. The crystals diffract to at least 2.5 A d spacings and are stable in the x-ray beam for 3 weeks. Crystals of the complex with the Lewis b (Leb) and Y human blood group determinants as the methyl glycosides, alpha-L-Fuc(1----2)beta-D-Gal(1----3)[alpha-L-Fuc(1----4)]beta-D-GlcNAc-OMe (where Fuc is fucose and -OMe is methoxy) and alpha-L-Fuc(1----2)beta-D-Gal(1----4)[alpha-L-Fuc(1----3)]-beta-D-GlcNAc- OMe, respectively, have also been grown and found to be isomorphous with the native lectin. Crystals have also been obtained with several derivatives of the Lewis b-OMe tetrasaccharide including that which has the 6-hydroxyl of the beta-D-GlcNAc unit replaced by iodine. In the latter case, the presence of the iodine atoms was established.