. 2021 Feb 24;296:100458. doi: 10.1016/j.jbc.2021.100458

Table 4.

Effect of FGFB and FGF12A on Ca²⁺ binding by CaM bound to Na_V1.2_CTD

CaM_1-148+ Na_V1.2_CTD	Ratio^a	Sites I and II			Sites III and IV
CaM_1-148+ Na_V1.2_CTD	Ratio^a	ΔG₁^b (kcal/mol)	ΔG₂^b (kcal/mol)	K_d-app^c (μM)	ΔG₁^b (kcal/mol)	ΔG₂^b (kcal/mol)	K_d-app^c (μM)
−	−	−6.27 ± 0.39	−13.78 ± 0.08	7.91	−6.04 ± 0.19	−12.09 ± 0.07	33.42
+ FGF12B	1:1:1	−6.00 ± 0.10	−14.51 ± 0.09	4.51	−5.44 ± 0.11	−10.27 ± 0.11	157.67
+ FGF12A	1:1:1	−7.18 ± 0.22	−14.99 ± 0.08	2.82	−5.31 ± 0.07	−12.91 ± 0.10	16.61

CaM_1-148+ Na_V1.2_CTD	Ratio^a	ΔG_1-app^b (kcal/mol)	ΔG_2-app^b (kcal/mol)	K_d-app^c (μM)	ΔG_1-app^d (kcal/mol)	ΔG_2-app^d (kcal/mol)	K_d-app^c (μM)
+ FGF12A	2:1:1	−7.59 ± 0.14	−15.41 ± 0.14	1.97	−7.61 ± 0.24	−16.05 ± 0.04	1.14
+ FGF12A	2:1:1	–	–	–	−5.03 ± 0.16	−10.89 ± 0.13	92.94

Solution Conditions: 50 mM HEPES, 100 mM KCl, 1 mM MgCl₂, 50 μM EGTA, 5 mM NTA, 1 mM DTT, pH 7.4, 22 °C. Fluorescence controls shown in Figures S7 and S8.

Stoichiometry of CaM:Na_V1.2_CTD:FGF12B or CaM:Na_V1.2_CTD:FGF12B.

Titrations fit to Equation 4. Average ΔG values based on three independent determinations monitoring Phe intensity.

K_d-app (apparent dissociation constant) was calculated from half of the average ΔG₂ value reported in this table.

Titrations fit to Equation 5. Average ΔG based on three independent determinations monitoring Tyr intensity.