Fig. 3: Structural comparison between xE1R/R2E and xWT.

The protomers were superposed based on the pore domains (residues 249-349), which resulted in an RMSD of 1.92 Å for all the Cα atoms. The shaded center panel shows the xE1R/R2E monomer colored according to the RMSD values calculated between the two aligned models. Blue indicates small movements and high similarity to the xWT structure, while orange represents larger movements highlighting the profound changes in the VSD in comparison to the other domains of the protein. a, left The VSD rotated by 30 degrees with regards to the center panel showing only the S0-S2 helices, xWT in blue and xE1R/R2E in orange. The Cα-Cα distances between the two structures are measured at the black lines and the angles at the dashed magenta curved line. a, middle The S2-S3L, and S3-S4 helices of the VSD and the S4-S5L. a, right An enlarged view of the S4/S4-S5L loop. The distance between the Cα atoms of xG235 is shown in black and the angle in magenta curved dashed line. b-e show the superposed structures focusing on the different domains. b The pore domain rotated by 90 degrees for clarity. c Distances between Cα atoms of residues Gly335, Ser339 and Leu343, from subunits across from one another, reveal a closed inner gate for both xE1R/R2E and xWT. d The intracellular helices HA and HB that interact with CaM (not shown in the panel for clarity), and HC. e CaM is attached to the VSD through interactions with the S2-S3L loop of the VSD in all structures. In the inset is an enlarged representation of the interactions between the residues of CaM, shown as ball and stick, and the VSD, shown as sticks.