Basepairs involving Hoogsteen edge of Cytosine and Sugar edge of Uracil

Basepairs involving Hoogsteen(H) edge of Cytosine and Sugar(S) 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
C:U h:s Cis	3	Optimized Model Structure	N3-O2...N4-N3 C6-O2'...C5-C1'
C:U h:s Trans	6	Optimized Model Structure	N3-O2...C5-N1 C6-O2'...N4-N3

Basepair

(type & Orientation)

*Frequency

Example

Hydrogen bonding atoms with their precursors

C:U h:s Cis

Optimized Model Structure

N3-O2...N4-N3

C6-O2'...C5-C1'

C:U h:s Trans

Optimized Model Structure

N3-O2...C5-N1

C6-O2'...N4-N3