Atomic structure
There is only one chemically distinct structure:
Nc1ncnc2c1ncn2[C@@H]1O[C@H](COP(=O)(O)O[C@@H]2[C@@H](COP(=O)(O)O[C@@H]3[C@@H](CO)O[C@@H](n4cnc5c(N)ncnc54)[C@@H]3O)O[C@@H](n3cnc4c(N)ncnc43)[C@@H]2O)[C@@H](O)[C@H]1O