Figure 2.

Uptake of Tc and Na⁺ into TetA(L)–H₆ proteoliposomes upon imposition of an outwardly directed proton gradient. The proteoliposomes were loaded at pH 7.0 with 100 mM NH₄Cl and then diluted into the following: (Left) ammonium-free buffer at pH 7.5 containing 50 μM [³H]Tc and 100 μM CoCl₂ (▪) alone or also containing either 10 mM NaCl (•) or 100 mM NH₄Cl (□); (Right) ammonium-free buffer at pH 8.5 containing 1 mM ²²Na⁺ alone (▪) or also containing either 50 μM Tc plus 100 μM CoCl₂ (•) or 100 mM NH₄Cl (□). Samples were filtered at intervals and analyzed as described in Materials and Methods.