Small-angle X-ray scattering investigations on seed proteins

The 11S globulins from sunflower and rape seeds as well as from broad beans were investigated by small-angle X-ray scattering. The proteins have molar masses of 3.0 x 105 g/Mol, 3.0 x 105 g/Mol and 3.5 x 105 g/Mol, respectively. The shapes of the molecules are nearly spherical. They consist in each case of 6 similarly structured subunits, arranged in the molecule as a trigonal antiprism in the dihedral point group symmetry 32. This structure seems to be typical for all 11S globulins from dicotyledons. The 7S globulin from french beans has a molar mass of 1.45 x 105 g/Mol. The shape of the molecule is disk-like. The molecule consists of three subunits separated by deep clefts filled with solvent. The molecule has a threefold symmetry axis perpendicular to the plane of the disk. (author)