Fig. 5: Structural impact of V181X (X = K, R, E, E⁰, F) on peripheral TM-interfaces and the pore of Orai1.

A Bottom view of the wt Orai1 with TM1 (residues 80–110), TM2 (residues 120–150), TM3 (residues 170–195) and TM4 (residues 235–262) shown as ribbons. Half of the protein is shown as solid ribbons while the other half is depicted as transparent ribbons with the position of the analyzed residues highlighted. Green square: the position of V181 shown in gray beads with the Cα shown as a blue bead. Blue square: the Cα from V181 is shown as a blue bead. B Left: rotation of V181 is shown for the wild-type and its mutants. The rotation angle is defined by using the vector formed by the center of the pore (defined by the geometric center of the Cα from residues 80–110) and the Cα residue of residue 181 and the vector formed by the Cα and Cγ from residue 181. Plots for the mutants are using dashed lines and with the following color code, V181K (purple), V181R (blue), V181E (red), V181E⁰ (teal), V181F (orange) and wt (black). Data for wt Orai1 are represented by a solid black curve. Right: bottom view of the channel with the TM region of the protein represented as transparent ribbons. Cα and Cγ from residues 181 used for the directional green vector are depicted with red and green beads respectively. The directional vector toward the pore in red is calculated using the Cα from residues 181 and the center of the pore (gray beads) defined by the geometric center of the Cα from residues 80 to 110. C Left: distance from the pore center (XY plane) of the charged moieties at position 181 (ammonium, carboxyl and guanidinium for V181K, V181E and V181R, respectively). Data for V181K, V181R, V181E, V181E⁰ and wt are presented in purple, blue, red, teal and black, respectively. Right: bottom view of the TMs of Orai1 depicted as ghostly ribbons. The Cα from residues 181 are shown as blue beads. Direction toward the center of the pore is presented using blue dashed line.