WT | N410K+T423K | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
pKBa | LogαNMSb | nc | koff (min−1)d | nc | pKB | LogαNMS | n | koff (min−1) | n | |
Gallamine | 5.98 ± 0.05 | −1.15 ± 0.05 | 6 | 0.0056 ± 0.0003^ | 4 | 3.91 ± 0.20* | −0.57 ± 0.11 | 3 | 0.010 ± 0.002 | 3 |
Strychnine | 5.48 ± 0.30 | 0.38 ± 0.06 | 3 | 0.0009 ± 0.0002^ | 3 | n.a | n.a | 4 | 0.004 ± 0.001 | 3 |
Brucine | 5.58 ± 0.34 | 0.14 ± 0.03 | 3 | 0.0014 ± 0.0003^ | 3 | 4.34 ± 0.34* | −0.36 ± 0.18 | 4 | 0.002 ± 0.001 | 3 |
n.a., not applicable, as no alteration of the specific binding of the radioligand was observed, and therefore, no estimate could be provided.
↵a Negative logarithm of the allosteric modulator equilibrium dissociation constant.
↵b Logarithm of the cooperativity factor for the interaction between the modulators and the orthosteric radioligand.
↵c Number of experiments performed.
↵d Dissociation rate constant of the [3H]NMS in the presence of the indicated ligand (control values in the absence of ligand: WT koff = 0.043 ± 0.003 min−1, N410K+T423K mutant koff = 0.007 ± 0.001 min−1).
↵* Significantly different from the corresponding value at the wild type (P < 0.05), Student’s t test.
↵^ Significantly different from koff with 100 μM atropine only (P < 0.05), one-way analysis of variance with Dunnett’s post-test.