Table 4.

Thermodynamic cycles parse the contributions of interfaces to activation

Location	Subtype	Ω(ACh) a	Ω(ACh+Mor) a	Rmut-Mor) b	Rmut-Oxa) b
M1	α3Y168Cβ2D190C α3Y168Cαβ2 α3β2D190C	5.7	2.2	0.52 0.29 10	1.9 1.2 19
M1	α3Y168Fβ2D190Q α3Y168Fαβ2 α3β2D190Q	18	4.9	0.57 0.066 7.1	1.6 1.5 19
A2	α3S125Yβ2W149A α3S125Yβ2 α3β2W149A	0.98	2.9	7.2 0.0076 7.3
A2	α3S125Cβ2Q39C α3S125Cβ2 α3β2Q39C	0.16	1.8	4.5 1.3 0.10
M3	α3Q37Cβ2A127C α3Q37Cβ2 α3β2A127C	0.64	1.15	1.7 5.3 3.3
M4	α3E173Cβ2R46C α3E173Cβ2 α3β2R46C	2.4	8.0	4.7 8.7 1.7
M4	α3E173Aβ2R46V α3E173Aβ2 α3β2R46V	15	0.57	9.0 1.4 4.2
A2/M3	α3S125Yβ2A127Y α3S125Yβ2 α3β2A127Y	3.2	1.4	1.2 0.0076 9.4

^aUsing values given in Tables 1–3, thermodynamic cycle Ω calculated as $\mathrm{\Omega }=\frac{EC50(WT)·EC50(\mathit{\text{mut ij}})}{EC50(\mathit{\text{mut i}})·EC50(\mathit{\text{mut j}})}$ for activation by ACh alone, ACh + 10 µM Mor or ACh + 10 µM Oxa; all with reference to wild type α3(32 receptors.

^bUsing values given in Tables 1–3, mutation-modulator Ɽ calculated as $Ɽ=\frac{EC50(WT,A)·EC50(\mathit{\text{mut}},A+M)}{EC50(WT,A+M)·EC50(\mathit{\text{mut}},A)}$ for activation by Mor or Oxa; all with reference to wild typeα3αβ32 receptor.