N
N9R
C8R
N
N7R
C5R
C6R
N
H
2
N6R
N
N1R
C1R(R)
C2R
N
N3R
C4R
O
O5'
C5'
C4'(R)
O
O4'
C3'(S)
O
H
O3'
C2'(R)
O
H
O2'
P
PA(R)
O
H
O1A
O
O2A
O
O3A
P
PB(R)
O
H
O1B
O
O2B
O
O3B
P
PG(S)
O
H
O1G
O
O2G
O
O3G
P
PD(S)
O
H
O1D
O
O2D
O
O3D
N
N1
C2
N
H
2
N2
N
H
N3
C4
O
O4
N
N5
C6
C6A
C7
N
H
N8
C9
C10