Fig. 2.

Structures of TRIC channels. (A) Comparison of vertebrate GgTRIC-A (Left) with prokaryotic and SaTRIC (Right). Ribbon drawings are viewed from the membrane (Top), and from the luminal or extracellular side (Bottom). Bound Ca²⁺ ion in GgTRIC-A is shown as a green sphere, and two bound Na⁺ ions in SaTRIC are shown as purple spheres. One protomer is colored spectrally from dark blue at its N terminus to red at its C terminus. Membrane boundaries were calculated by OPM server. (B) Superimposition of the protomer structure of GgTRIC-A and XlTRIC-B. Stereo view of the superimposed C_α backbones, oriented as in A. The coloring for GgTRIC-A protomer is as in A, and XlTRIC-B protomer is in gray.