Figure 4. Counter‐transported ion binding site.

• A
  Purified EAAT1_CRYST takes up L‐glutamate in liposomes loaded with K⁺ or Rb⁺, but not with choline (Ch⁺), or with Ch⁺ and Ca²⁺. Plots depict data as in Fig 3A.
• B
  Superimposition of Na⁺/transmitter and Rb⁺ bound EAAT1_CRYST structures, respectively, with tranD depicted in orange (Na⁺/transmitter) and pink (Rb⁺). TM4 and UCPH₁₀₁ are omitted for clarity. Black mesh depicts the anomalous‐difference map contoured at 3.5σ around the tranD. Rb⁺ coordination is shown in the inset. Residue numbering corresponds to EAAT1_WT, and the coordination distance (angstrom) is parenthesis.

Data information: In (A) bar plots depict averages and s.e.m. values of three independent experiments (empty circles) performed in triplicate.