STRUCTURE OF BARIUM GUANOSINE 5'-MONOPHOSPHATE

2Ba2+ .2C10H10N5O8p2-.12H2O, M(r) = 1209.22, orthorhombic, P2(1)2(1)2(1), a = 21.37 (2), b = 22.04 (1), c = 8.66 (1) angstrom, V = 4076 (1) angstrom3, Z = 4, D(x) = 1.970 g CM - 3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 21.01 cm-1, F(000) = 2400, T = 296 K, R = 0.061 for 2602 observed reflections [I > 3.0-sigma(I)]. Two each of barium and guanosine 5'-monophosphate make up the asymmetric unit. Each Ba ion has nine ligands which include the N(7) of each guanosine, sugar hydroxyls, a phosphate 0 atom, water molecules and bridging water molecules. The guanosines have anti glycosidic torsional angles and C(2')-endo sugar puckers. The guanosines are packed in columns with a channel of coordinated Ba ions through the crystal. There is no base-base stacking and no base-base hydrogen bonding.