The Base Pair Directory
| CUbase pairs with two standard hydrogen bonds |
| base | potential H-bond donor/acceptor sites |
cytosine C  |
C(aa3) N3... C2 O2... |
C(da3) N4-H... C4 N3... |
uracil U  |
U(1da3) O4...C4 N3-H... |
U(2da3) N3-H...C2 O2... |
| CUbase pairs with 4 heavy-atom H-bond donor/acceptor sites |
| base pair H-bond motif | structure images |
U(1da3)...C(da3) UC 4-carbonyl-amino, N3-N3 O4...H-N4 C4 C4 N3-H...N3 |
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U(2da3)...C(da3) UC N3-N3, 2-carbonyl-amino N3-H...N3 C2 C4 O2...H-N4 |
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| There are no UC base pairs with 3 heavy-atom H-bond donor/acceptor sites. |