FIGURE 8.

Examination of the energetics of preSSU binding and import in R130A:ppi1 and F67A:ppi1 chloroplasts. A, ATP dependence of preSSU import into isolated wild type, ppi1, WT:ppi1, R130A:ppi1, or F67A:ppi1 chloroplasts. Energy-depleted chloroplasts equivalent to 35 μg of chlorophyll were incubated with [³⁵S]preSSU in the presence of increasing amounts of ATP, as indicated, at 23 °C for 10 min. Quantification of the data from triplicate experiments is presented in the graph. Lane 1 in the upper panel shows 10% of the in vitro translation (IVT) products added to each reaction. Lane 1 in the bottom two panels shows 20% of the in vitro translation products added to each reaction. B, nigericin- and apyrase-treated chloroplasts were incubated for 5 min in either the presence or absence of 10 mm glycerate. Quantification of the data from triplicate experiments is presented in the graph. All samples were analyzed by SDS-PAGE and phosphorimaging. Dashed lines indicate that the illustrations were generated from different regions of the same SDS-polyacrylamide gel using samples from the same experiment. The error bars correspond to S.D.