Skip to main content
. 2022 Jan 12;13:290. doi: 10.1038/s41467-021-27915-z

Fig. 2. Comparison of the transmembrane regions between the prestin structure and the Slc26a9 structure (in two different conformations).

Fig. 2

A Superposition of the transmembrane-domain structures of prestin (colored in cyan) and Slc26a9 in the “inward-open” conformation (colored in orange, PDB 7CH1). The structures have been superimposed through the TM13 and TM14 helices from the “gate” domain. B Close-up view showing a portion (TM3, TM5, TM8, TM10, TM13 and TM14 helices) of the overlaid transmembrane domains (as shown in panel A). C Close-up view of the overlaid pair of helices (TM3 and TM10) from the two structures in the orientations shown in panel A. D Superposition of the transmembrane domain structures of prestin (colored in cyan) and Slc26a9 in the intermediate conformation (colored in gray, PDB 6RTF) (superimposed through the gate’s TM13 and TM14 helices). E Close-up view of the overlaid (TM3, TM5, TM8, TM10, TM13, and TM14) helices from the two structures in the orientations shown in panel (D). F Close-up view showing the offset between the pair of helices (TM3 and TM10) from the two structures in the orientations shown in panel (D). G–I Side-by-side comparisons of the opening between the TM8 helix (from the core domain) and the TM14 helix (from the gate domain) on the intracellular side of the membrane for the three structures. Consistent with the expectation, this opening (defined by the angle between the TM8 helix and TM14 helix) is the larger in the Slc26a9 structure (inward-open conformation) and the smaller in the prestin structure. The angle between TM8 and TM14 helices of prestin and of Slc26a9 is 57° (for prestin), 61° (for Slc26a9, the intermediate conformation), and 67° (for Slc26a9, the “inward-facing”, open conformation). See also Supplementary Fig. 6.