2OQP

Solution structure of human interleukin-21


SOLUTION NMR
NMR Experiment
ExperimentTypeSample ContentsSolventIonic StrengthpHPressureTemperature (K)Spectrometer
13D_15N-separated_NOESY0.8mM IL21 U-15N, 20mM phosphate, 50mM NaCl, 1mM NaN390% H2O/10% D2O50mM NaCl5.5ambient300
23D_13C-separated_NOESY0.8mM IL21 U-15N,13C, 20mM phosphate, 50mM NaCl, 1mM NaN3100% D2O50mM NaCl5.5ambient300
32D NOESY0.8mM IL21 U-15N,13C, 20mM phosphate, 50mM NaCl, 1mM NaN3100% D2O50mM NaCl5.5ambient300
4HNHA0.8mM IL21 U-15N, 20mM phosphate, 50mM NaCl, 1mM NaN390% H2O/10% D2O50mM NaCl5.5ambient300
NMR Spectrometer Information
SpectrometerManufacturerModelField Strength
1BrukerAV600
2VarianINOVA800
NMR Refinement
MethodDetailsSoftware
simulated annealingA total of 1235, 2994 and 449 peaks from 15N-separated, 13C-separated NOESY and 2D NOESY spectra, respectively, were included in structure calculations. Together with chemical shifts for the assigned resonances, the NOEs were analyzed with Cyana using the candid protocol for automatic NOE assignment and structure calculation. Additional sources of structural information were included in the calculations. Thus two disulfide bonds were enforced between Cys43 and Cys94, and between Cys50 and Cys97. This disulfide pattern has been established for the hIL-21 molecule through an analysis which combined protease cleavage, Edman degradation, and MS. Test calculations without disulfide bond constraints supported this pattern. Chemical shift values for HA, CA, CB, N and CO atoms were analyzed to predict phi and psi backbone angles using the computer program Talos. Talos gave good predictions for 78 residues, and 156 angle phi/psi angle constraints were included in the calculations with an uncertainty of 30 degrees. From the HNHA spectrum 72 J(HA-HN) scalar coupling constants were extracted and included in the structure calculations. Hydrogen bond constraints were added for 20 backbone amide protons which exchange slowly in deuterium exchange experiments. Hydrogen bond patterns were identified based on structures calculated without hydrogen bond constraints.CYANA
NMR Ensemble Information
Conformer Selection Criteriastructures with the lowest energy
Conformers Calculated Total Number64
Conformers Submitted Total Number20
Representative Model1 (lowest energy)
Additional NMR Experimental Information
DetailsThe structure was determined using triple-resonance NMR spectroscopy.
Computation: NMR Software
#ClassificationVersionSoftware NameAuthor
1refinementCYANA1.0.8Guntert P.
2data analysisTalosCornilescu G., Delaglio F., Bax A.
3data analysissparky3.110Goddard T.D., Kneller D.G.
4processingFELIX2004Accelrys
5collectionXWINNMR3.5Bruker