Fig. 1: Overall closed- and open-state structures of KCNQ1 + KCNE1.
From: Secondary structure transitions and dual PIP2 binding define cardiac KCNQ1-KCNE1 channel gating
a Top and side views of KCNQ1 density maps in the apo condition, and (KCNQ1 + KCNE1)EM density maps in apo and in the presence of PIP2. An endogenous PC molecule was observed in KCNQ1APO, and an endogenous PIP2 molecule was observed in (KCNQ1 + KCNE1)APO, while two PIP2 molecules, PIP2-1 and PIP2-2, were observed in each subunit of (KCNQ1 + KCNE1)PIP2. Color codes: KCNQ1APO (yellow), (KCNQ1 + KCNE1)APO (blue), (KCNQ1 + KCNE1)PIP2 (green), KCNE1 (red), PIP2-1 (orange), PIP2-2 (dark green), and CaM (pink). b Structure models of KCNQ1APO, (KCNQ1 + KCNE1)APO, and (KCNQ1 + KCNE1)PIP2. c KCNE1-induced horizontal expansion of the VSD (from 85.1 Å to 93.3 Å for S2–I161), and ~10° rotation of the VSD (counterclockwise, based on the residue I132 from the middle of S1 to the center pore axis). Structures were aligned to the filter. d KCNE1-induced vertical expansions of the S2–S3 linker and the cytosolic domain (~6 Å). For clarity, CaM in the KCNQ1APO was colored gray, and CaM in the (KCNQ1 + KCNE1)APO was colored rust red.
