A
4 cyclic N (4 cyclic DB)
1 NH2
Double Ring
G
Deoxyguanosine
3 Cyclic N (3 cyclic DB)
1 Cyclic NH
1 NH2 (bottom right)
1 DB O (top)
Double Ring
T
1 cyclic N (1 DB)
1 cyclic NH
2 DB O (Top and Bottom Right)
1 CH3 (Top left)
Single Ring
C
2 Cyclic N (2 Cyclic DB)
1 DB O
1 NH2
Single Ring
A–T
C—G
U
1 Cyclic N (1 Cyclic DB)
1 Cyclic NH
2 DB O
Single Ring