Figure 1.

Voltage dependence and sequence comparison of HCN1, HCN2 and chimeric HCN2 with C-linker and CNBD of HCN1. (A) Representative current traces in the inside-out configuration and conductance–voltage curves obtained in the presence and absence of 10 µM cAMP. The same patch was recorded in both conditions. Tail currents from HCN2 (n = 19 patches), HCN2/1 (n = 19), and HCN1 (n = 21) were normalized to the maximum fitted tail current recorded in the presence of cAMP for each patch. Data presented are mean ± SEM. (B) Sequence alignment and secondary structures of mouse HCN1–4. The 18 residues that differ between HCN1 and HCN2 are highlighted in red.