TABLE 5.
T1 relaxation rate-estimated distances of phenacetin protons from the heme iron of CYP1A1 and CYP1A2
SEs for measurements are shown in parentheses. Errors in the T1 values were those reported by the fitting routine. Errors in the reported distances (r) were determined by propagation of error from the T1 calculation. Generally, the error is <10%.
| Protona | CYP1A1b |
CYP1A2c |
||||||
|---|---|---|---|---|---|---|---|---|
| T1, Fe3+ | T1, Fe −CO2+ | rd | Re | T1, Fe3+ | T1, Fe −CO2+ | rd | Re | |
| Å | Å | |||||||
| 2,6 | 2.73 (0.25) | 3.53 (0.21) | 6.10 (0.24) | 7.97 | 2.35 (0.18) | 3.0 (0.21) | 7.07 (0.52) | 8.25 |
| 3,5 | 2.993 (0.1) | 2.37 (0.12) | 6.13 (0.41) | 8.03 | 1.85 (0.1) | 2.13 (0.11) | 7.37 (0.65) | 8.32 |
| OCH2 | 1.62 (0.12) | 1.65 (0.19) | 8.84 (9.02)f | 10.21 | 1.58 (0.15) | 1.8 (0.18) | 7.27 (1.32) | 8.14 |
| COCH3 | 1.33 (0.07) | 1.44 (0.04) | 6.46 (0.83) | 9.21 | 1.35 (0.07) | 1.45 (0.06) | 7.75 (1.23) | 9.44 |
| CH3 | 1.6 (0.06) | 1.89 (0.06) | 5.94 (0.32) | 9.95 | 1.44 (0.07) | 1.61 (0.06) | 7.34 (0.68) | 8.64 |
See Fig. 1 for the numbering scheme of the protons for phenacetin.
[CYP1A1] = 0.778 μM; [phenacetin] = 7.9 mM; KS (CYP1A1) = 57 μM.
[CYP1A2] = 0.833 μM; [phenacetin] = 7.4 mM; KS (CYP1A2) = 17 μM.
Values were calculated by r = [9.78 × 1016T1P (αm S(S + 1)τc)]1/6.
Values were obtained by averaging the 20 lowest-energy conformations selected by the docking program (see MD Docking with Distance Restraints).
Distance could not be determined with accuracy.