Figure 3.

Uptake of Tc and cobalt into TetA(L)–H₆ proteoliposomes upon imposition of an outwardly directed proton gradient. The proteoliposomes were loaded with NH₄Cl at pH 7.0 as described in Materials and Methods and were diluted into ammonium-free buffer at pH 7.5 containing 50 μM [³H]Tc and 100 μM nonradioactive CoCl₂ (•); 50 μM nonradioactive Tc and 100 μM ⁶⁰CoCl₂ (▪); 50 μM [³H]Tc alone (○); or 100 μM ⁶⁰CoCl₂ alone (□). Samples were filtered at intervals and processed as described in the text. The numbers at the top of the figure indicate the Tc/Co ratios calculated from total accumulation at the points shown by the lines.