Figure 9.

Normalized junctional conductance (G_j/G_{j max}) monitored in Xenopus oocyte pairs expressing Cx32 or Cx32’s CT1 mutants. Channels made of Cx32 mutants in which two or more CT1-arginines (R215, R219, R220, R223 and R224) are replaced by neutral-polar residues (asparagine, N or threonine, T) are much more sensitive to CO₂ than controls. In contrast, channels in which the R-residues are replaced with another basic residue (lysine, K) or histidine (H), as well as those with preserved R215 (4R/N#1), behave like Cx32 wild-type channels. From Reference [116].