Mapping of the twelve TM4 residues on the current X-ray model for the four transmembrane helices.

<p>Since the twelve amino acid positions analyzed fall only in the four α helical bundle domain of Cx26, here we show only (<b>A</b>) TM1 (medium blue), TM2 (cyan) TM3 (green) and TM4 (orange). The orientation of the Cx26 subunit is the same as in Fig. 1 with the extracellular loops at the top of the image. The mutant residues have been colored coded such that mutations that caused -trafficking are shown in purple, mutations that make gap junctions but unstable hemichannels are black and mutations that make stable gap junctions and hemichannels are indicated in red. Two positions, I203 and L205, have different phenotypes for the each of two mutations at these positions. These residues are dark blue. (<b>B</b>) Side chain interactions for these residues are between TM4 and TM1 and (<b>C</b>) TM4 and TM3. Note that the A197, N206S and T208 face the lipid bilayer. Note the mutant phenotypes are not mapped to any particular face of TM4.