Figure 7.

Interactions of Ca²⁺ with RyR1 residues in multiple functional states. Shown are the predicted interactions of Ca²⁺ with RyR1-WT and RyR1-E3893Q/E3967Q, E3893V/E3967V, and T5001A variants under nominally Ca²⁺-free (PDB code 5TB0) and Ca²⁺/ATP/caffeine (PDB code 5TAQ and 5TAL) conditions. Residues displaying electrostatic interactions with Ca²⁺ in the Ca²⁺/ATP/caffeine state are depicted in a stick representation, and the backbone of RyR1 is shown in a ribbon representation. Ca²⁺ is shown as a green sphere in Ca²⁺-bound states and as a hollow sphere in Ca²⁺-free states. Strong electrostatic interactions (d < 3.5 Å) are shown as blue dashed lines, and weak electrostatic interactions (3.5 < d < 4 Å) are shown as red dashed lines between Ca²⁺ and RyR1 residues. Distances less than 3.5 Å formed interresidue contacts and are shown as blue dashed lines.