1FL8

HYPERMODIFIED NUCLEOSIDES IN THE ANTICODON OF TRNALYS STABILIZE A CANONICAL U-TURN STRUCTURE

SOLUTION NMR

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NMR Experiment
Experiment	Type	Sample Contents	Solvent	Ionic Strength	pH	Pressure	Temperature (K)	Spectrometer
1	2D NOESY	1.5mM natural abundance RNA; 10mM phosphate buffer; 50mM KCl; 50mM NaCl; 10mM MgCl2	90% H2O/10% D2O	120mM	7	ambient	285
2	2D NOESY	1.5mM natural abundance RNA; 10mM phosphate buffer; 50mM KCl; 50mM NaCl; 10mM MgCl2	90% H2O/10% D2O	120mM	7	ambient	303
3	DQF-COSY	1.5mM natural abundance RNA; 10mM phosphate buffer; 50mM KCl; 50mM NaCl; 10mM MgCl2	90% H2O/10% D2O	120mM	7	ambient	303
4	1H-31P-COSY	1.5mM natural abundance RNA; 10mM phosphate buffer; 50mM KCl; 50mM NaCl; 10mM MgCl2	90% H2O/10% D2O	120mM	7	ambient	303
5	1H-31P-hetero-TOCSY-TOCSY	1.5mM natural abundance RNA; 10mM phosphate buffer; 50mM KCl; 50mM NaCl; 10mM MgCl2	90% H2O/10% D2O	120mM	7	ambient	303

NMR Spectrometer Information
Spectrometer	Manufacturer	Model	Field Strength
1	Varian	UNITYPLUS	600
2	Varian	UNITY	500

NMR Refinement
Method	Details	Software
used H5-H6 distances for distance calculations then simulated annealing/molecular dynamics in vacuo then restrained minimization in vacuo	123 NOE-derived restraints, 15 hydrogen bond restraints, 102 lower/upper bound restraints, 161 dihedral restraints, 68 chiral restraints	VNMR

NMR Ensemble Information
Conformer Selection Criteria	structures with the lowest energy
Conformers Calculated Total Number	35
Conformers Submitted Total Number	20
Representative Model	4 (closest to the average,lowest energy)

Additional NMR Experimental Information
Details	This structure was determined using standard 2D homonuclear techniques and standard 1H-31P 2D correlation experiments.

Computation: NMR Software
#	Classification	Version	Software Name	Author
1	collection	VNMR	6.1B	Varian
2	processing	VNMR	6.1B	Varian
3	data analysis	VNMR	6.1B	Varian
4	processing	Felix		MSI
5	data analysis	Felix		MSI
6	structure solution	Discover		MSI
7	refinement	Discover		MSI