Table 1.
Integral volumes of the four histidine signals normalized to C2H2. The third column shows the predicted ratios modulated by non-uniform magnetization transfer due to different JCH values. The predicted ratios were calculated on the basis of in-house measured JCH values. The fourth column presents the measured ratios for the highest histidine concentration measured by standard HSQC without correction by calibration factors. The penultimate and ultimate columns show the observed ratios for the highest histidine concentration observed by Q-HSQC and QUIPU-HSQC, respectively.
| Coupling Constant [Hz] |
Predicted Ratio |
Without Averaging |
Q-HSQC | QUIPU-HSQC | |
|---|---|---|---|---|---|
| C2 H2 | 140.8 | 1 | 1.00 ± 0.4% | 1.00 ± 1% | 1.00 ± 4% |
| C3 H3A/B | 128.3/117.4 | 0.94 | 0.97 ± 2% | 0.87 ± 2% | 0.83 ± 2% |
| C5 H5 | 193.4 | 0.75 | 0.82 ± 2% | 1.01 ± 0.8% | 0.54 ± 19% |
| C7 H7 | 211.4 | 0.57 | 0.61 ± 5% | 0.93 ± 3.6% | 0.48 ± 6% |