Fig. 1

Schematic illustrations of the peptides of Ca_V1.2 channel, CaM and its mutants. a NT is a N-terminal peptide containing a CaM-binding site called NSCaTE (see text). The C-terminal tail was divided into three parts as illustrated. CT1 contains regulatory regions (shown as boxes), Ca²⁺-binding EF-hand motif (EF) and two CaM-binding motifs (preIQ and IQ). Amino acid (a.a.) numbers (guinea-pig cardiac Ca_V1.2) of peptides are shown in the parentheses. LI–II, LII–III and LIII–IV represent intracellular loops between homologous repeats of I to IV. b Schematic illustrations of CaM and its mutants (CaM₁₂, CaM₃₄ and CaM₁₂₃₄). Closed circles represent normal Ca²⁺-binding sites in N-lobe (N) and C-lobe (C) of CaM, open circles with X represent mutated Ca²⁺-binding sites, which are unable to bind with Ca²⁺. Substitutions of a.a. are shown with one-letter codes of a.a. c A.a. sequences of human CaM. The sequences of Ca²⁺-binding sites 1–4 and mutated points are shown in boxes and red color, respectively (color figure online)