1N9J

Solution Structure of the 3D domain swapped dimer of Stefin A

SOLUTION NMR

NMR Experiment
Experiment	Type	Sample Contents	Solvent	Ionic Strength	pH	Pressure	Temperature (K)	Spectrometer
1	HNCA	1.2mM Stefin A U-15N; 50mM phosphate buffer pH 5.5, 100mM KCl, 5mM Azide; 90% H2O, 10% D2O	90% H2O/10% D2O		5.5	ambient	308
2	HNCO	1.2mM Stefin A U-15N; 50mM phosphate buffer pH 5.5, 100mM KCl, 5mM Azide; 90% H2O, 10% D2O	90% H2O/10% D2O		5.5	ambient	308
3	HN(CA)CB	1.2mM Stefin A U-15N; 50mM phosphate buffer pH 5.5, 100mM KCl, 5mM Azide; 90% H2O, 10% D2O	90% H2O/10% D2O		5.5	ambient	308
4	TOCSY-HSQC	1.2mM Stefin A U-15N; 50mM phosphate buffer pH 5.5, 100mM KCl, 5mM Azide; 90% H2O, 10% D2O	90% H2O/10% D2O		5.5	ambient	308
5	NOESY-HSQC	1.2mM Stefin A U-15N; 50mM phosphate buffer pH 5.5, 100mM KCl, 5mM Azide; 90% H2O, 10% D2O	90% H2O/10% D2O		5.5	ambient	308
6	15N-isotope-filtered NOESY	1mM Stefin A U-15N,13C,2H; 50mM phosphate buffer pH 5.5, 100mM KCl, 5mM Azide; 90% H2O, 10% D2O	90% H2O/10% D2O		5.5	ambient	308

NMR Spectrometer Information
Spectrometer	Manufacturer	Model	Field Strength
1	Bruker	DRX	600
2	Bruker	DRX	800

NMR Refinement
Method	Details	Software
simulated annealing	Distance restraints (NOEs and hydrogen bonds) were taken from the data used for the stefin A monomer structure (Martin et al., 1995), except those involving residues V48-G50 and N77-L80 where chemical shift perturbation was observed following resonance assignment. The NOEs were specified as intermolecular and intramolecular according to domain-swapped topology inferred from isotope filtering experiments. An additional hydrogen bond restraint was included between 48 and 50 based on evidence from protection experiments on the dimer (Jerala and Zerovnik, 1999). Dihedral restraints (phi and psi) were determined using the 1H-alpha, 15N, 13C-alpha, 13C-beta and 13C' chemical shifts and the program TALOS (Cornilescu et al., 1999). Where TALOS gave a `poor' match, the experimental phi dihedral angle was taken from the data used for the stefin A monomer structure calculation.	XwinNMR

NMR Ensemble Information
Conformer Selection Criteria
Conformers Calculated Total Number
Conformers Submitted Total Number	1
Representative Model	1 (minimized average structure)

Computation: NMR Software
#	Classification	Version	Software Name	Author
1	collection	XwinNMR	2.6	Bruker
2	data analysis	Felix	2000	MSI
3	refinement	X-PLOR	3.1	BRUNGER

RCSB PDB Core Operations are funded by the National Science Foundation (DBI-1832184), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM133198.