ISOLATION AND MOLECULAR STRUCTURE OF VITAMIN B12 5'-PHOSPHATE

1. A method for obtaining and purifying a precursor of vitamin B12 from Propionibacterium shermanii is described. The method involves heat treatment of the bacteria, phenol extraction of the crude extract, chromatographic separations, and crystallization from acetone-water (8:1, v/v). The heat treatment leads to roughly a 40-fold increase in final yield of the precursor compared to the concentration in teh unheated bacteria. 2. The precursor is shown to be Vitamin B12 5′-phosphate by X-ray diffraction analysis of the air dried crystals. The crystal structure was solved using the tangent formula and refined with the method of least squares. 3. The vitamin B12 5′-phosphate structure is isomorphous with that of the vitamin except for the additional phosphate. The 5′-phosphate is the gauche-gauche conformation, the ribose puckering is C2′-exo, and the 3′-phosphate makes an angle of 67° with C3′ and the propionamide. The α-glycosidic bond is 16° out of the plane of the 5,6-dimethylbenzimidazole because of steric interactions. The corrin nucleus is bowed, and the acetamide and propionamide side chains form hydrogen bonds with water molecules and adjacent molecules in the crystal. © 1969.