. Author manuscript; available in PMC: 2012 May 15.

Published in final edited form as: Biochem J. 2011 May 1;435(3):711–722. doi: 10.1042/BJ20101726

Table 3.

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)
Peptide	K_d (μM)	h	K_d (μM)	h
None	12.0 ± 0.2	1.4 ± 0.1	3.78 ± 0.03	2.14 ± 0.03
Cx50p^141–166	22.7 ± 0.6	0.8 ± 0.1	3.18 ± 0.03	2.74 ± 0.07
Cx44p^129–150	11.6 ± 0.1	1.5 ± 0.1	0.93 ± 0.02	2.20 ± 0.10
Cx43p^136–158	14.5 ± 0.1	1.6 ± 0.2	1.16 ± 0.02	2.10 ± 0.10

All of the experiments were conducted three times (n = 3). K_d and the Hill coefficient (h) were obtained by fitting the titration curve to eqn (7). 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) reports the Ca²⁺ binding to the C-domain of CaM.