FIGURE 7.

CD studies of the interaction between Cx32CT and CaM. CD spectra of the CaM/wild-type Cx32CT (A), CaM/Cx32CT-R219H (B), CaM/Cx32CT-R230C (C), and CaM/Cx32CT-F235C (D) interactions. Top panels, CD spectra of CaM in the presence of 5 mm EGTA or 5 mm CaCl₂ and a 1:1 CaM/Cx32CT mixture after subtracting the contribution from buffer and added Cx32CT. Spectra were recorded at 7 °C in 25 mm Tris, 100 mm KCl, pH 7.0. Lower panels, CD spectra of the Cx32CT (solid line) and the calculated difference spectrum (dashed line) by subtracting the spectrum of Ca²⁺-CaM from that of the Ca²⁺-CaM/Cx32CT mixture.