Figure 1. The anion permeation pathway... | Rockefeller University Press

Figure 1.

The anion permeation pathway of TMEM16A with the high-affinity Ca2+binding site occupied. One subunit of TMEM16A with its extracellular (top) and intracellular (bottom) sides is shown. The anion permeation pathway is drawn as a teal mesh, and the α-helices 3–8 surrounding the pore are shown in gray. The green spheres are two Ca2+ ions sitting in the Ca2+ pocket of site 1. Note that residues of the hydrophobic gate (I641) and Ca2+ pocket (N650 and E654) are part of TM6. Thus, when Ca2+ binding occurs, the translational movement of TM6 is outwardly transmitted to open the hydrophobic gate. The side chains of the extracellular cluster of basic residues (olive), the hydrophobic gate (blue), two lysines at the middle of the pore (yellow), and the Ca2+ pocket of site 1 (orange) involved in anion selectivity were modeled as sticks.

The anion permeation pathway of TMEM16A with the high-affinity Ca ²⁺ binding site occupied. One subunit of TMEM16A with its extracellular (top) and intracellular (bottom) sides is shown. The anion permeation pathway is drawn as a teal mesh, and the α-helices 3–8 surrounding the pore are shown in gray. The green spheres are two Ca²⁺ ions sitting in the Ca²⁺ pocket of site 1. Note that residues of the hydrophobic gate (I641) and Ca²⁺ pocket (N650 and E654) are part of TM6. Thus, when Ca²⁺ binding occurs, the translational movement of TM6 is outwardly transmitted to open the hydrophobic gate. The side chains of the extracellular cluster of basic residues (olive), the hydrophobic gate (blue), two lysines at the middle of the pore (yellow), and the Ca²⁺ pocket of site 1 (orange) involved in anion selectivity were modeled as sticks.