Fig. 5: Structural model for pH-gating of the TWIK1 channel.
From: Structural Basis for pH-gating of the K+ channel TWIK1 at the selectivity filter
a, b Model for selectivity filter gating of TWIK1 gating by pHext viewed from (a) the membrane plane and (b) the extracellular side. TWIK1 is conductive at a high pH. At low pH, H122 protonation results in conformational changes that disrupt K+ coordination sites S0 and S1, seal the top of the selectivity filter, displace the helical cap to block extracellular ion access pathways, and dilate a lateral membrane opening to permit acyl chain binding to the channel cavity.
