Table 1.

NMR restraints and structural statistics.

Number of experimental restraints
Distance restraints	411
imino-imino	16
intra-residue	198
inter-residue	190
>5 Å	7
Dihedral restraints	172
C3′-endo	62
RNA-A stems	110
Hydrogen bonding distance restraints	62
Residual dipolar coupling	74
Base planarity restraints	11
r.m.s. deviations from experimental restraints
Distance (Å)	0.0387 ± 0.0013
Dihedral (°)	0.2353 ± 0.1966
r.m.s. deviations from the idealized geometry
Bonds (Å)	0.0064 ± 0.0001
Angle (°)	2.5077 ± 0.0115
Impropers (°)	1.8760 ± 0.1089
Heavy-atoms r.m.s. deviation (Å)a
All	1.16

^aAveraged r.m.s. deviations between an average structure and the 10 converged structures were calculated. The converged structures did not contain experimental distance violations of >0.5 Å or dihedral violations of >5°.