Figure 1: Homology models illustrate a possible molecular mechanism for ClC-1 common gating.
From: Molecular determinants of common gating of a ClC chloride channel
Shown are ClC-1 models based on homology to the crystallographic coordinates of (a). ClC-ec1 E148Q (PDB id: 1OTU), (b) ClC-ec1 (PDB id: 1OTS) and (c) CmClC coordinates (PDB id: 3ORG). Panels (a) and (b) depict the open and closed conformation of the protopore gate, respectively. Panel (c) depicts the conformation of E232 that we hypothesize corresponds to the closed common gate. Each panel shows: at left, a representation of the pertinent model; middle, a cartoon representation of the relationship between key side chains and anion-binding sites; right, an alternative view depicting the relationship between residues V292 and Y578 for the respective model. Coloured figures show relevant ClC-1 helices as ribbons coloured blue (helix F), yellow (helix R) and magenta (helix I). The side chains of residues E232 (Eext), Y578 (Ycen) and V292 are depicted as sticks, and coloured by atom. Spheres coloured in green depict anion-binding sites, Sext (e), Scen (c) and Sint (i), modelled based on respective crystallographic coordinates for each panel. Dashed lines in (c) represent a possible hydrogen bond between the carboxylate group of E232 and the phenolic-hydroxyl group of Y578. For sequence alignments and a structural overview of the protein regions examined in this study please refer to Supplementary Fig. S1.
