Table 1. Structural statistics (20 structures out of 300 calculated, PDB code 2n0r).

NMR distance and dihedral constraints
Distance restraints
Total distance restraints	208
Intra-residue	73
Inter-residue	135
Sequential (|i-j|=1)	96
Non-sequential (|i-j|>1)	39
Hydrogen bonds	34
Total dihedral angle restraints	174
Glycosidic angle χ	18
Sugar pucker	54
Backbone	102
Based on A-form geometry	43
Structure statistics	In vacuum	Solvent refined
Violations (mean and s.d.)
Distance constraints (Å)	0.0043±0.0005	0.007±0.003
Dihedral angle constraints (°)	0.03±0.02	0.28±0.07
Max. distance constraint violation (Å)	0.05	0.24
Max. dihedral angle violation (°)	0.7	3.4
Deviations from idealized geometry
Bond lengths (Å)	0.000182±0.00006	0.0023±0.0001
Bond angles (°)	0.461±0.002	0.64±0.02
Impropers (°)	0.319±0.001	0.41±0.02
Average pairwise r.m.s.d. (Å)
All RNA heavy (2–9,14–24)	0.9±0.2	1.0±0.2
All RNA backbone (2–9,14–24)	0.8±0.2	1.0±0.2
Kink-turn backbone (4–6,17–22)	0.7±0.2	0.8±0.2