Figure 4.

Models of the post-TM C-terminal segment (residues 305–330). (A) Helical wheel representation in which residues are colored according to polarity: small hydrophobic (grey); large hydrophobic (black); negatively charged (red) and positively charged (blue). (B) Helical wheel representation in which residues are colored according to their degree of conservation, from yellow (highly conserved) to blue (not conserved). (C) “Parallel Dimer” model in which the highly conserved hydrophobic residues self associate; this arrangement was used in the models of the open and closed states. (D) “Antiparallel Dimer” model in which the small residues face pack next to each other; this arrangement was used in a tentative model of the inactivated state.