Fig. 6

Determination of Ca²⁺ transport via AtAPC2. Time dependent uptake of [⁴⁵Ca] via full-length AtAPC2 (a) and via N-terminally truncated AtAPC2 (b) reconstituted into P_i (black rhombs) and non-loaded liposomes (gray squares). (c) Effects of rising MgCl₂ concentrations on [⁴⁵Ca] transport into P_i loaded (dark gray bars) and non-loaded (light gray bars) AtAPC2 proteoliposomes. Transport media contained 20 μM [⁴⁵Ca] and were additionally supplemented with 100 μM non-labeled ATP and the indicated concentrations of MgCl₂. For determination of the Mg²⁺-effects on Ca²⁺ transport via AtAPC2 uptake was allowed for 10 min (given as nmol mg protein⁻¹ h⁻¹). Data represent mean values of three independent replicates. Standard errors are indicated