The Ca²⁺-CaM–TRPV1-CT interface. (A) Aligned sequences of Ca²⁺–CaM-binding peptides with antiparallel 1–10 motifs (TRPV1-CT and CaMKIIa; Meador et al., 1993) and 1–14 motifs (smooth muscle light chain kinase [Meador et al., 1992], skMLCK [Ikura et al., 1992], and CaMKI [Clapperton et al., 2002]), and parallel 1–16 motifs (CaMKKα [Osawa et al., 1999] and cCAMKKp [Kurokawa et al., 2001]). Residues are colored as follows: blue, positively charged; red, negatively charged; orange, hydrophobic. Hydrophobic anchors are boxed in black. (B) Lobe-specific interactions, featuring hydrophobic pockets on CaM, with the CaM C-lobes and N-lobes shown in surface representation. The views of the C-lobes and N-lobes are related to Fig. 2 A by rotations of +80° and −100° around the horizontal axis, respectively. CaM residues that contact TRPV1-CT35 (interatomic distances of ≤4.2 Å) are colored according to their side-chain properties (orange, hydrophobic; blue, positively charged; red, negatively charged; green, polar), and selected ones are labeled in black. Selected TRPV1 residues are labeled in cyan. (C) CaM-agarose pulldowns of MBP-fused TRPV1-CT35 peptides (residues 767–801). A Coomassie-stained gel of pulldowns in the absence (EGTA) or presence (Ca²⁺) of calcium is shown as a representative result of three independent experiments. An MBP–α-Gal protein construct, expressed from the unmodified vector, was used as a negative control. (D) Sequence map of CaM residues in contact with TRPV1-CT35 (interatomic distances of ≤4.2 Å). CaM N-lobe, C-lobe, and TRPV1-CT35 residues are mustard, orange, and cyan, respectively. Interacting CaM residues making at least one polar contact are boxed.