Lobe-related concentration- and Ca2+-dependent interactions of calmodulin with C- and N-terminal tails of the CaV1.2 channel

Table 1 Parameters for the bindings of CaM and its mutants to CT1

	CaM				CaM₁₂				CaM₃₄				CaM₁₂₃₄
	EGTA	100 nM	10 μM	2 mM	EGTA	100 nM	10 μM	2 mM	EGTA	100 nM	10 μM	2 mM	EGTA	100 nM	10 μM	2 mM
\({ \rm{K}_{\rm{d}_{1} }\, {({\upmu}{\text M})}}\)	1.17	2.19	0.40	0.39	2.73	2.00	3.19	1.48	2.64	3.90	2.45	2.54	3.07	3.39	2.53	2.41
\({\rm{B}}_{{\max_{1} }\, {({\rm mol}/{\rm mol})}}\)	0.28	0.15	0.58	0.91	0.54	0.43	0.85	0.84	0.60	0.70	0.61	0.70	0.70	0.70	0.63	0.62
\( {\rm{K}_{{\rm{d}_{2} }\, {({\upmu}{\text M})}}} \)			33.27	10.92			29.67	25.30	6.93	7.08	7.44	6.75	6.93	9.44	8.70	7.03
\({\rm{B}}_{{\max_{2} }\, {({\rm mol}/{\rm mol})}} \)			0.44	0.83			0.49	0.83	0.51	0.57	0.61	0.64	0.35	0.62	0.63	0.62
R²	0.977	0.843	0.928	0.961	0.987	0.986	0.995	0.990	0.974	0.978	0.994	0.968	0.973	0.958	0.946	0.969

Data from the GST pull-down assay shown in Figs. 2, 3 were analyzed with a software SigmaPlot 10.0 and with single or double Hill equations (see “Materials and Methods”). \( K_{{d_{1} }} \) and \( K_{{d_{2} }} \): apparent dissociation constants, \( B_{{\max_{1} }} \) and \( B_{{\max_{2} }} \): the maximum bindings, R ²: coefficient of determination. Blanks in \( K_{{d_{2} }} \) and \( B_{{\max_{2} }} \) meant a better fit with the single-site model than the double-site model

ISSN: 1880-6562