Phaseolin, the main reserve globulin in seeds of the French bean (Phaseolus vulgaris L.), has been purified for sedimentation equilibrium analysis. The major protomer at neutral pH has a molecular weight of 150 000±5 000 which associates to a tetrameric form of molecular weight 596 000±20 000 at pH 4.5. The trimeric nature of the protomer is apparent from protein crosslinking experiments. Initial structural studies were made using optical rotatory dispersion and circular dichroism measurements. Two different crystal forms of the protein have been grown and characterised by X-ray diffraction; one of these forms appears suitable for high resolution X-ray analysis.
French beanPhaseolus vulgarisphaseolinseed globulinseed storage protein