Fig. S3.

Structural features of mutants C932L (A) and C932F (B). Side views with cytoplasmic side up are shown, based on PDB ID code 3WGV [protomer B (chain A in the PDB file)], with C932 being replaced. Selected residues (rat α₁ numbering) are shown as sticks and colored according to the elements (carbon, gray; oxygen, red; nitrogen, blue), except that the substituent is highlighted by the yellow color of carbon atoms. The bound Na⁺ ions are shown as blue spheres. Broken lines with numbers indicate distances in angstroms.