Structure of the mono potassium salt of 5' adp di hydrate
Adamiak, D.A.; Saenger, W.
Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry 36(11): 2585-2589
Crystals of the title compound, K+ .cntdot. C10H14-N5O10P2- .cntdot. 2H2O, were grown at pH 4 from a water/ethanol mixture. They have space group P21212 with a = 28.502 (5), b = 10.461 (2), c = 6.321 (2) .ANG., Z = 4 and Dc = 1.76 Mg m-3. The structure was solved from 1726 3-dimensional X-ray diffraction data and refined to Rw = 9.3%. The ribose adopts the C(2')-endo conformation, the orientation about the C(4').sbd.C(5') bond is gauche,gauche and the heterocycle is anti with respect to the ribose. The pyrophosphate O(5').sbd.P(1).sbd.O(6').sbd.P(2) chain is in a staggered conformation, with P.sbd.O.sbd.P angle 130.degree. and P(1).sbd.O(6') 1.65, P(2).sbd.O(6') 1.60 .ANG., K+ is coordinated to pyrophosphate oxygens, to ribose O(2'), to heterocycle N(3) and to water. The 2 other negative charges of ADP are compensated by protons at N(1) and at O(23) of the pyrophosphate. This crystal structure is isomorphous with RbADP.cntdot.H2O.