The molecule is an organophosphate oxoanion obtained by deprotonation of the phosphate OH groups of Gp[2'-5']Ap[3']; major species at pH 7.3. It is a conjugate base of a Gp[2'-5']Ap[3'].
[(2R,3S,4R,5R)-2-[[[(2R,3R,4R,5R)-2-(2-amino-6-oxo-1H-purin-9-yl)-4-hydroxy-5-(hydroxymethyl)oxolan-3-yl]oxy-oxidophosphoryl]oxymethyl]-5-(6-aminopurin-9-yl)-4-hydroxyoxolan-3-yl] phosphate