Table 4.
Summary of 13C σ2-CSA parameters for U-[13C,15N]-histidine.
| R1423 |
R2034,2 |
ROCSA |
||||
|---|---|---|---|---|---|---|
| # | δσ (ppm) | ησ | δσ (ppm) | ησ | δσ (ppm) | ησ |
| Cα | 16.9 ± 0.6 | 0.46 ± 0.11 | 17.6 ± 0.9 | 0.58 ± 0.16 | 15.7 ± 1.6 | 0.55 ± 0.19 |
| Cβ | 14.5 ± 2.2 | 0.93 ± 0.44 | … | … | 8.1 ± 2.6 | 0.97 ± 0.85 |
| Cγ | 75.8 ± 2.9 | 0.87 ± 0.15 | 77.3 ± 0.5 | 0.80 ± 0.03 | 69.0 ± 4.3 | 1.00 ± 0.11 |
| Cδ | 71.7 ± 3.4 | 1.00 ± 0.24 | 71.0 ± 2.2 | 0.88 ± 0.06 | 67.6 ± 0.3 | 1.00 ± 0.57 |
| Cɛ | 71.8 ± 2.1 | 0.83 ± 0.08 | 71.0 ± 0.9 | 0.76 ± 0.11 | 70.0 ± 3.9 | 0.76 ± 0.09 |
| Co | 66.0 ± 1.1 | 1.00 ± 0.45 | 68.1 ± 4.7 | 0.93 ± 0.17 | 64.8 ± 3.6 | 1.00 ± 0.04 |
1
Note: R2034 and R1423 symmetry sequences were employed for σ2-CSA recoupling. The rf field strengths were 83.3 and 87.5 kHz, respectively, and the MAS frequency was 25 kHz. TPPM 1H decoupling with rf field strength of 100 kHz was applied during the RNCSA period. The results of ROCSA recoupling are presented for comparison.
2
The experimental and simulated 13C CSA line shapes for each carbon site are shown in the supplementary material.46