Deoxyadenosine triphosphate consits of the purine adenine. A purine consists of two fused ring structures, a six carbon ring and a five carbon ring. Adenine diverges from the basic structure of a purine as it has an amine group at position 6 of the six carbon ring. This purine base hydrogen bonds to complementary thymine bases. DATP also consists of a deoxyribose sugar (a pentose sugar) and three phosphate groups. Unlike ATP, dATP posseses only a hydrogen bonded to a carbon in the pentose sugar, where as ATP posses a hydroxyl group bonded to a carbon atom. DATP's are used by DNA polymerase to form complementary base pairs with thymine bases on a corresponding 3' to 5' template DNA strand or antisense strand. The process with which this occurs is known as nucleotidyl transfer, in which a phosphodiester bond is broken, releasing a pyrophosphate molecule (two phosphate groups bonded together). Its molecular formula is C10H16N5O12P3 . DATP is known as a triphosphate.