SOLUTION NMR
| NMR Experiment | ||||||||
|---|---|---|---|---|---|---|---|---|
| Experiment | Type | Sample Contents | Solvent | Ionic Strength | pH | Pressure | Temperature (K) | Spectrometer |
| 1 | TRNOESY | 1.7mM PACAP21; 40mM PACAP receptor; 80mM phosphate buffer (pH 6.3) | 90% H2O/10% D2O | 0.41 | 6.3 | ambient | 298 | |
| 2 | TRNOESY | 1.7mM PACAP21; 40mM PACAP receptor; 80mM phosphate buffer (pH 6.3) | 90% H2O/10% D2O | |||||
| NMR Spectrometer Information | |||
|---|---|---|---|
| Spectrometer | Manufacturer | Model | Field Strength |
| 1 | Bruker | DRX | 800 |
| NMR Refinement | ||
|---|---|---|
| Method | Details | Software |
| Iterative relaxation matrix analysis (IRMA) and simulated annealing (SA) | The structures are calculated by SA protocol of X-PLOR based on a total of 387 TRNOE-derived distance restraints obtained from the IRMA refinement. | X-PLOR |
| NMR Ensemble Information | |
|---|---|
| Conformer Selection Criteria | structures with the lowest energy |
| Conformers Calculated Total Number | 200 |
| Conformers Submitted Total Number | 25 |
| Representative Model | 12 (closest to the average) |
| Additional NMR Experimental Information | |
|---|---|
| Details | Both TRNOE and NOE cross peaks were observed in the spectrum: the former reflects the conformation of PACAP21 in the receptor-bound form, while the latter reflects that of unbound PACAP21. Upon addition of a higher affinity ligand, PACAP27, the TRNOE cross peaks were selectively eliminated due to a competitive inhibition of the specific binding of PACAP21 to the receptor. Accordingly, the subtraction of these two spectra yields TRNOE-related cross peaks exclusively. |
| Computation: NMR Software | ||||
|---|---|---|---|---|
| # | Classification | Version | Software Name | Author |
| 1 | structure solution | X-PLOR | 3.1 | Brunger, A.T. |
| 2 | iterative matrix relaxation | IRMA | 30-Jul-90 | Kaptein, R. |
| 3 | refinement | X-PLOR | 3.1 | Brunger, A.T. |
