Crystallization and preliminary X-ray diffraction studies of the soluble 14 kDa beta-galactoside-binding lectin from bovine heart.

The soluble 14 kDa beta-galactoside-binding lectin from bovine heart, a member of the S-type lectin family, has been crystallized in a form suitable for X-ray diffraction analysis. The crystals, in the absence of a saccharide ligand, diffract beyond 2.5 A resolution. They are obtained from polyethylene glycol 6000 at pH 6.0. Crystals grow as monoclinic plates, space group P2(1), with cell dimensions: a = 35.47 A, b = 64.33 A, c = 58.78 A and beta = 91.7 degrees. The asymmetric unit contains two molecules related by a 2-fold non-crystallographic axis. Two lectin monomers in the asymmetric unit give a Vm of 2.4 A3/Da, i.e. a solvent content of approximately 50%. The complex of lectin with the saccharide ligand, N-acetyllactosamine, crystallizes in the space group P2(1)2(1)2 with cell dimensions: a = 63.55 A, b = 82.13 A and c = 62.39 A. Crystals of this complex diffract beyond 2.0 A resolution. Two complexes in the asymmetric unit lead to a Vm value of 2.8 A3/Da (57% solvent).

Crystallization of pancreatic procolipase and of its complex with pancreatic lipase.

The human pancreatic lipase-porcine procolipase complex has been crystallized in space group P3(2)21 (a = b = 80.3 A and c = 251 A) from a solution containing polyethylene glycol, NaCl and beta-octyl glucoside. The crystals diffract to 2.6 A on a synchrotron beam. The complex in the presence of bile salts and phospholipids crystallizes in a tetragonal space group P4(2)2(1)2 (a = b = 133.4 A, c = 92.6 A). Crystals of procolipase alone were obtained under slightly different experimental conditions (space group I432, a = b = c = 164.3 A).

Crystallization and preliminary X-ray diffraction study of Lathyrus ochrus isolectin II complexed to the human lactotransferrin N2 fragment.

Isolectin II (LOL II) isolated from the seeds of Lathyrus ochrus has been crystallized in the presence of the N2 fragment (18,500 Da) isolated from human lactotransferrin, which contains an N-acetyllactosamine type biantennary glycan linked to Asn137. This is the first example of a legume lectin crystallized with an N-glycosylprotein. Crystals of the LOL II-N2 complex belong to the tetragonal space group (P4(1)2(1)2 or the enantiomorph) with cell dimensions: a = b = 63.5 A, c = 251.9 A. They diffract well up to at least 3.5 A resolution and more weakly up to 2.8 A resolution. Assuming one functional half-entity in the asymmetric unit, an alpha, beta monomer complexed to one N2 fragment (24,500 Da + 18,500 Da) would give a Vm of 2.95 A3/Da and a solvent content of approximately 58%. SDS/polyacrylamide gels of the dissolved crystals show the presence of both the LOL II and N2 fragment.