Structure-based mechanism of RyR channel operation by calcium and magnesium ions
Fig 5
Possible interactions between the EF-hand and S23 in the open RyR1 and RyR2 structures.
A – Overlay of the EF-hand region in the open RyR1 (7m6l, cyan) and RyR2 (7ua9, magenta) structures aligned at their S23 loops (out of the image plane). Note the differences in the EF1 and EF2 positions and almost the same positions of the Central domain and U-motif segments. The RyR1 residue sequence numbers are given for orientation. B – Possible residue interactions between the EF-hand region (left) and S23* loop (right) in the open RyR1 (cyan) and RyR2 (magenta) structures. The structures in B are rotated by 30° counterclockwise about their x, y, and z axes relative to their orientation in A. Dotted red lines -– structurally possible H-bonds between the interacting residues. The spatial arrangement of all primed, open, and inactivated structures is compared for RyR1 and RyR2 in S1 Fig.