Crystallization of Helix pomatia agglutinin (HPA), a protein from the edible snail

Crystals of Helix pomatia agglutinin (HPA) have been grown by the hanging-drop technique using polyethylene glycol as the precipitant at 293 K. Over a period of one to two weeks the crystals grew to maximum dimensions of 0.10 × 0.05 × 0.02 mm. The crystals belong to space group P6₃22, with unit-cell dimensions a = b = 63.3, c = 105.2 Å and Z = 12 identical monomers of M_r = 13 kDa, aggregating into two 78 kDa hexameric protein molecules per unit cell, each with symmetry 32 (D₃). The diffraction pattern extends to 3.6 Å at 293 K.