Table III.
Substitutions at Position 3 of the GBP Ca2+ Binding Loop: Effects on Metal Binding and Dissociation*
| Site | Sidechain | k off(Tb3+) | K D(Tb3+) | K D(Ca2+) | ||||
|---|---|---|---|---|---|---|---|---|
| (s−1) | (μM) | (μM) | ||||||
| N136D | Asp | 8.8 ± 0.6 × 10−5 | 0.03 ± 0.02 | >600 | ||||
| WT(N136) | Asn | 6.41 ± 0.03 × 10−3 | 3.0 ± 0.9 | 1.6 ± 0.4 | ||||
| N136S | Ser | 8.46 ± 0.09 × 10−2 | 0.7 ± 0.1 | 3.7 ± 0.5 | ||||
| N136T | Thr | 9.28 ± 0.06 × 10−2 | 0.6 ± 0.1 | 13.3 ± 0.9 | ||||
| N136V | Val | 9.4 ± 0.2 × 10−2 | 0.5 ± 0.3 | 10.3 ± 0.4 | ||||
| N136Q | Gln | 2.21 ± 0.04 × 100 | 3.0 ± 0.7 | 26 ± 3 |
*
Errors are standard deviation for n ≥ 7.