Basepairs involving WatsonCrick(W) edge of Adenine and Hoogsteen(H) edge of Uracil is shown. Highlighted examples are found from RNA crystal structures obtained from PDB.

Base pairs stabilized by C-H...N/O interactions along with N-H...N/O hydrogen bonds

Basepair

(type & Orientation)

*Frequency

Example

Hydrogen bonding atoms with their precursors

A:U w:h Cis

1

Optimized Model Structure

N7-N6...O4-N3

C8-N1...C5-C2

A:U w:h Trans

0

Optimized Model Structure

C8-N1...C2-C5

C4-C2...O4-N3

* 1st and 2nd numbers in Frequency column represent the numbers of occurences as base pairs and as base triplets, respectively.