Table 2. Hydrogen bonds in the UACG tetraloop^a.

Hydrogen bond	Distance between heavy atoms (Å)	Distance between proton and heavy atom (Å)
G13 N1-H1…U10 O2	2.84 ± 0.01	1.88 ± 0.02
U10 O2′-HO2′…G13 O6	3.02 ± 0.08	2.37 ± 0.04
C12 N4-H42…A11 O2P	2.89 ± 0.15	1.99 ± 0.17
A11 O2′-HO2′…G13 N7	3.24 ± 0.12	2.60 ± 0.08
A11 O2′-HO2′…G13 O6	3.88 ± 0.14	3.34 ± 0.20
C9 O2′-HO2′…U10 O4′	3.45 ± 0.26	3.16 ± 0.49
C9 O2′-HO2′…U10 O5′	3.41 ± 0.14	3.76 ± 0.18
G13 O2′-HO2′…G14 O4′	3.54 ± 0.46	3.31 ± 0.86
G13 O2′-HO2′…G14 O5′	3.83 ± 0.45	3.79 ± 0.36

^aAverage values ± SD calculated for the 10 final structures.