C22
C21
C20
C19
C18
C17
C16
O
O16
C15
N
H
2
N15
C14
C13
C12
C11
C10
N
H
N3G
P
PG(R)
O
H
O1G
O
O2G
N
H
N3B
P
PB(S)
O
H
O1B
O
O2B
O
O3A
P
PA(S)
O
H
O1A
O
O2A
O
O5'
C5'
C4'(R)
O
O4'
C2'(R)
O
H
O2'
C3'(S)
O
H
O3'
C1'(R)
N
N9
C4
N
N3
C2
N
H
2
N2
N
H
N1
C6
O
O6
C5
N
N7
C8