Figure 5.

Metal-ion interactions in the transport sites of E1⋅H⁺₇₇₁-PLB. (A) Location of the nine different positions occupied by K⁺ (yellow spheres) in the transport sites of E1⋅H⁺₇₇₁-PLB; each position is labeled from 1 to 9. The dashed circles show the approximate location of the transport sites I and II. TM helices are represented by gray ribbons and cation-binding residues are shown as sticks. (B) Percentage of time K⁺ spends in each position shown in (A). Data are presented as the mean ± SE (n = 3). (C) Distance distributions between residue pairs E771_Cα-D800_Cα, E771_Cα-G801_Cα, and E771_Cδ-D800_Cγ. Distance distributions of E1⋅2K⁺ (upper panel) were calculated from a 1 μs trajectory reported recently by our group (64). Distance distributions of E1⋅ H⁺₇₇₁-PLB (lower panel) were calculated by combining all three trajectories of the complex. To see this figure in color, go online.