. 2009 Apr 8;96(7):2832–2848. doi: 10.1016/j.bpj.2008.12.3941

Table 4.

Effects of Cx peptides binding on the metal-binding properties of CaM

Peptide	N-domain (sites I and II)^∗		C-domain (sites III and IV)^†		EGTA-induced Ca²⁺ release^‡ (k_obs, s⁻¹)
Peptide	K_d (μM)	n_Hill	K_d (μM)	n_Hill	EGTA-induced Ca²⁺ release^‡ (k_obs, s⁻¹)
None	14.59 ± 0.03	1.5 ± 0.1	1.95 ± 0.03	2.1 ± 0.1	> 400.0
Cx44_129–150	11.62 ± 0.05	1.5 ± 0.1	0.93 ± 0.02	2.2 ± 0.1	5.3 ± 0.2
Cx43_136–158	14.48 ± 0.02	1.6 ± 0.2	1.16 ± 0.02	2.1 ± 0.1	> 400.0

All experiments were repeated for at least three trials. K_d and the Hill coefficient (n_Hill) were obtained by fitting the titration curve with Eq. 3.

^∗

Phenylalanine fluorescence (λ_ex = 250 nm; λ_em = 280 nm) reports the Ca²⁺ binding to the N-domain of CaM.

^†

Tyrosine fluorescence (λ_ex = 277 nm; λ_em = 320 nm) reflects the Ca²⁺ binding to the C-domain of CaM.

^‡

The observed rates of EGTA-induced Ca²⁺ release from CaM or the CaM-peptide complexes were obtained by fitting the far UV CD signal at 222 nm as a function of time using a single exponential function.