Crystallization and preliminary crystallographic study of an invertebrate C-type lectin, CEL-I, from the marine invertebrate Cucumaria echinata

CEL-I is a GalNAc-specific carbohydrate-binding protein (lectin) isolated from the sea cucumber Cucumaria echinata. This protein belongs to the widely distributed C-type lectin family of animal lectins, which require Ca²⁺ for their carbohydrate-binding ability and play important roles in various molecular-recognition processes in organisms. CEL-I was crystallized with 2-methyl-2,4-pentanediol using the hanging-drop vapour-diffusion technique. The CEL-I crystals belong to the monoclinic space group C2, with unit-cell parameters a = 92.38 (3), b = 69.94 (3), c = 76.69 (3) Å, β = 136.46 (2)°. Diffraction data were collected to 2.0 Å resolution using synchrotron radiation. The asymmetric unit contains one CEL-I molecule.