Crystallization and preliminary X-ray analysis of apo-S100 beta and S100 beta with Ca2+

Crystals of a bovine neurotrophic factor S100 beta with and without Ca2+ bound has been crystallized by vapor diffusion from solutions of polyethylene glycol. The crystals of S100 beta with Ca2+ bound were monoclinic and belong to space group P21 with unit cell dimensions a = 36.2 A, b = 55.63 A, c = 48.39 A and beta = 111.77 degrees. The asymmetric unit contains two molecules (one dimer) which exhibit an approximate 222 point symmetry. The crystals of apo-S100 beta were tetragonal and belong to space group P4(1) with unit cell dimensions a = b = 56.04 A, c = 111.7 A. The asymmetric unit contains four molecules (two dimers) which exhibit 422 point symmetry. Both these crystal forms diffract to greater than 1.9 A resolution.