Fig. 4: TMDs of BTR1 in the inward-facing conformation.
From: Structural insights into the conformational changes of BTR1/SLC4A11 in complex with PIP2
a, b Cryo-EM map and structural model of the BTR1 dimer in the inward-facing state as viewed from the side. The color schemes are the same as in Fig. 1 (c–e). c, d Ion permeation pathway of BTR1 in the inward-facing state conformation (c) and the pore radius values along the pathway (d). e, f Structural alignment of TMDs of BTR1IF/R125H and BTR1OF/APO as viewed from the side (e) and the bottom (f). The shift directions of the transmembrane helices when transitioning from the outward-facing state to the inward-facing state are shown as red arrows. The alignment RMSDs of the gate domains and core domains are labeled below. g Structural alignment of the gate domains of BTR1IF/R125H and BTR1OF/APO. The helices with marked displacement are labeled in black. The shift direction of helices are shown as red arrows. h The centroid shift of the pore region during the state transition process. The centroids of residues P437 and P723 of BTR1IF/R125H and BTR1OF/APO are shown as green and gray spheres, respectively. The centroid shift is shown as red dotted arrow. The shift direction of helices are shown as red arrows.
