The crystal and molecular structure of inosine‐5'‐phosphate

The crystal and molecular structure of inosine-5'-phosphate has been determined by the symbolic addition method. The crystal obtained from an aqueous methanol solution contains one water and one methanol molecule per nucleotide and belongs to space group P2,212, with a=23.33, b=4.788, c= 15"44/~, Z=4. The phosphate oxygen atoms are distributed at the two rotational positions around the P-O ester bond. The torsion angle of the base with respect to the sugar, ~bcN is 20 °, in the anti conformation. The ribose puckering is C(3")-endo, which is different from the molecule of inosine-5'phosphate in the salt crystals. The conformation about the C(4')-C(5') bond is gauche-gauche. Large tunnels run through the structure parallel to the b axis. Water and methanol molecules fill the tunnels, but their positions are considerably disordered.