X-ray crystallographic and chromatographic characterization of the crystals of Ca2+―calmodulin complexed with bee venom melittin

Crystals of calmodulin complexed with both Ca2+ and melittin, a peptide from bee venom, have been grown from 2-methyl-2,4-pentanediol solution by using the hanging drop method of vapour diffusion. The crystals belong to space group P2(1)2(1)2(1) with a = 97.3(9) A, b = 56.5(0) A, c = 33.4(9) A and Z = 4. Analyses of the dissolved crystals by high performance liquid chromatography show that the crystals contain a 1:1 complex of calmodulin and melittin. An asymmetric unit contains one such complex and the solvent content of the crystals is 47.5% (v/v).