Table 2:
Data Collection and Refinement Statistics
| Collection | pH 4 | pH 5 | pH 7 |
|---|---|---|---|
| Space group | P42212 | P42212 | P42212 |
| Unit cell dimensions (Å) | a = b = 74.43 c= 152.10 | a = b = 74.30 c= 152.30 | a = b = 74.74 c= 152.57 |
| Resolution range (Å) | 50.00 – 2.60 (2.64 – 2.60)a | 50.00 – 2.45 (2.49 – 2.45)a | 50.00 – 2.54 (2.58 – 2.54)a |
| Total reflections (observed / unique) | 784334 / 13907 | 262087 / 16508 | 592952 / 15012 |
| Rmeasb (%) | 8.6 (90.1) | 9.2 (141.2) | 6.4 (72.9) |
| Rpimc (%) | 3.0 (39.4) | 3.5 (54.1) | 1.9 (22.3) |
| I/σI | 22.8 (1.4) | 26.7 (1.2) | 36.6 (2.0) |
| Completeness (%) | 99.5 (95.1) | 97.5 (96.6) | 99.6 (95.8) |
| CC½d | 96.2 (79.5) | 93.2 (69.1) | 98.4 (93.9) |
| Multiplicity | 7.7 (4.4) | 6.9 (6.6) | 10.0 (8.7) |
| Wilson B (Å2) | 58.0 | 58.6 | 58.7 |
| Refinement | |||
| R-factor / Rfree (%)e | 18.07/23.49(H2O) | 18.99/24.81(H2O) | 19.22/24.88 |
| 20.49/27.08(O2) | 18.88/24.04(O2) | ||
| Total atoms - protein / solvent | 2520 | 2537 | 2548 |
| Atomic displacement parameters (Å2) | |||
| - protein | 78.0 | 76.8 | 83.1 |
| - solvent | 75.0 | 67.7 | 79.6 |
| - hemef | 76.1 / 69.3 | 66.8 / 67.6 | 71.2 / 73.5 |
| - ligandf | 75.2 / 46.5 | 52.5 / 64.4 | 106.3 / 81.6 |
| rms deviation from ideality | |||
| - bond distances (Å) | 0.008(H2O) | 0.009(H2O) | 0.008 |
| 0.009(O2) | 0.008(O2) | ||
| - bond angles (°) | 0.995(H2O) | 1.080(H2O) | 0.971 |
| 1.012(O2) | 0.919(O2) | ||
| Ramachandran plotg | |||
| - residues in favored regions (%) | 95.6(H2O) | 95.0(H2O) | 96.0 |
| 94.3(O2) | 94.6(O2) | ||
| - outliers | 0.0(H2O) | 0.67(H2O) | 1.00 |
| 0.34(O2) | 1.34(O2) | ||
| Molprobity score | 1.92(H2O) | 1.93(H2O) | 2.03 |
| 1.96(O2) | 1.90(O2) | ||
| Fe-O distance | 2.85/2.59(H2O) | 2.34/2.49(H2O) | 1.86/1.79(O2) |
| 1.84/1.78(O2) | 1.89/1.82(O2) | ||
a
Numbers in parentheses relate to the highest resolution shell.
b
Rmeas is the redundancy-independent merging R factor [61].
c
Rpim is the precision-indicating merging R factor [62].
d
Percentage of correlation between intensities from random half-sets of data [63].
e
Rfree was calculated with 5% of the reflections, chosen randomly.
f
Atomic displacement parameters for Chain A/Chain B for HbII-HbIII with H2O as a ligand in the protein at pH 4 and pH 5.
g
Calculated with the program MOLPROBITY [64].