Crystallization and initial crystallographic characterization of a vicilin-type seed storage protein from Pinus koraiensis.

The cupin superfamily of proteins includes the 7S and 11S seed storage proteins. Many members of this family of proteins are known allergens. In this study, the Korean pine (Pinus koraiensis) vicilin-type 7S seed storage protein was isolated from defatted pine-nut extract and purified by sequential gel-filtration and anion-exchange chromatography. Well diffracting single crystals were obtained by the vapor-diffusion method in hanging drops. The crystals belong to the primitive cubic space group P2(1)3, with unit-cell parameters a = b = c = 148.174 A. Two vicilin molecules were present in the asymmetric unit and the Matthews coefficient was determined to be 2.90 A(3) Da(-1), with a corresponding solvent content of approximately 58%. A molecular-replacement structural solution has been obtained using the program Phaser. Refinement of the structure is currently under way.