Table 4 Kinetic and thermodynamic parameters of conformational exchange in apo human I-BABP deduced from 15N backbone relaxation dispersion NMR measurements (10 °C).
From: Ligand entry in human ileal bile acid-binding protein is mediated by histidine protonation
(A) | pH = 6.3 | pH = 6.8 | pH = 8.0 | |
|---|---|---|---|---|
global fit analysis | ||||
cluster I | cluster II | |||
kex (s−1) | 836 ± 59 | 294 ± 40 | 1467 ± 161 | 1453 ± 194 |
pE (%) | 3.1 ± 0.2 | 1.8 ± 0.2 | 4.4 ± 0.3 | 5.7 ± 0.4 |
kGE (s−1) | 26 ± 3 | 5.3 ± 0.9 | 65 ± 8 | 83 ± 12 |
kEG (s−1) | 810 ± 57 | 289 ± 39 | 1402 ± 154 | 1370 ± 183 |
(B) | pH = 5.4 | |||
individual fit analysis | ||||
kex (s−1) | pE (%) | |||
Thr3 | 54 ± 22 | 8 ± 5 | ||
Thr73 | 10 ± 44 | 19 ± 6 | ||
Gly76 | 1170 ± 322 | 21 ± 8 | ||
Val91 | 1852 ± 216 | 24 ± 3 | ||
Tyr97 | 1057 ± 170 | 0.3 ± 0.4 | ||
Thr100 | 479 ± 63 | 0.7 ± 0.2 | ||
Ser101 | 651 ± 104 | 23 ± 5 | ||
Glu110 | 480 ± 94 | 0.4 ± 0.3 | ||
