Experiment: 1N0C

Stability of cyclic beta-hairpins: Asymmetric contibutions from side chains of hydrogen bonded cross-strand residue pair

SOLUTION NMR

NMR Experiment
Experiment	Type	Sample Contents	Solvent	Ionic Strength	pH	Pressure	Temperature (K)	Spectrometer
1	DQF-COSY	5 mM peptide, unbuffered	90% H2O/10% D2O	0	5.0	1 atm	298
2	2D TOCSY	5 mM peptide, unbuffered	90% H2O/10% D2O	0	5.0	1 atm	298
3	2D ROESY	5 mM peptide, unbuffered	90% H2O/10% D2O	0	5.0	1 atm	298
4	2D ROESY	5 mM peptide, unbuffered	100% D2O	0	5.0	1 atm	298
5	2D COSY-35	5 mM peptide, unbuffered	100% D2O	0	5.0	1 atm	298

NMR Spectrometer Information
Spectrometer	Manufacturer	Model	Field Strength
1	Bruker	DRX	500

NMR Refinement
Method	Details	Software
Distance geometry and restrained molecular dynamics with chemical shift refinement	100 structures were calculated using distance geometry. The 80 structures of lowest penalty function were refined using the Sander module of AMBER (v6.0). The calculation employed 93 distance restraints, 15 dihedral angle restraints and 37 chemical shift restraints. The 20 structures of lowest violation energy were chosen to represent the structure. There are no violations of the input restraints > 0.1 A or 2 degrees. The rms. difference between calculation and observed chemical shifts is 0.12 ppm. 81% of the backbone geometries are in the most favourable region of the Ramachandran plot. The backbone heavy atom rmsd from the mean structure is 0.29+/-0.08 A.	XwinNMR

NMR Ensemble Information
Conformer Selection Criteria	structures with the least restraint violations
Conformers Calculated Total Number	80
Conformers Submitted Total Number	20
Representative Model	1 (closest to the average,fewest violations)

Additional NMR Experimental Information
Details	Resonance assignments were made using standard 2D homonuclear techniques

Computation: NMR Software
#	Classification	Version	Software Name	Author
1	collection	XwinNMR	v3.1	bruker
2	data analysis	Felix	980	accelrys
3	structure solution	DGII	980	Tim Havel
4	refinement	Amber	6.0	Case, Kollman et al.
5	structure solution	Amber	6.0