TABLE 2.

Structural statistics for the U6 ISL and S_P-ISL

	U6 ISL		SP-ISL
	With dipolar coupling data	Without dipolar coupling dataa	With dipolar coupling data	Without dipolar coupling dataa
Structures
Accepted	20	40	17	17
Calculated	100	200	100	100
NOE-derived distance restraints (per nucleotide)	506 (21.1)	521 (21.7)	322 (13.4)	322 (13.4)
Dihedral restraints	145	145	144	144
Hydrogen-bond restraints	25	25	25	25
Dipolar coupling restraints	31	—	40	—
RMSD, all heavy atoms to the mean structure (Å)
Overall (62–71, 73, 75–85)	0.79 ± 0.30b	1.46 ± 0.4	1.05 ± 0.3b	2.14 ± 0.8
Internal loop (66–68, 78–81)	0.46 ± 0.2c	0.44 ± 0.3	0.49 ± 0.2c	0.58 ± 0.4
NOE violations (>0.5 Å)	0	0	0	0
Ave. dihedral violations (>5.0°)	0	0	0	0
Ave. NOE RMSD (Å)	0.027	0.018	0.029	0.041
Ave. dihedral RMSD (°)	0.640	1.270	0.710	0.761
Ave. RDC RMSD (Hz)	2.38 ± 0.11	—	2.35 ± 0.16	—

^aPreviously determined (Huppler et al. 2002).

^bThe RMSD for all heavy atoms excluding bulged nucleotides (62–71, 73, 75–85) is 1.16 ± 0.4 Å between U6 ISL and S_P-ISL RNAs.

^cThe internal loop (66–68, 78–81) RMSD for all heavy atoms is 0.55 ± 0.3 Å between U6 ISL and S_P-ISL RNAs.