The influence of Cdc6 mutants on pre-RC formation. Pre-RC assembly was performed as described in the methods section. A 30% load of the pre-RC proteins is shown in lanes 1–6. The use of the mutants is indicated in the figures. The gel was silver stained to visualize the proteins; however, the smallest subunit of the Orc1–6 complex stains only weakly. (A) Cdc6, Cdc6 K114E (Walker A) and Cdc6 R332E (sensor-2) were used in pre-RC assays in the presence of ATP (lanes 8–16) or ATPγS (lane 7). Pre-RCs were washed with a low salt buffer (lanes 7–9, 11, 12, 14 and 15) or a high salt buffer (lanes 10, 13 and 16). (B) Cdc6, Cdc6 E224G (Walker B) and Cdc6 N263A (sensor-1) were used in pre-RC assays in the presence of ATP (lanes 8–16) or ATPγS (lane 7). Pre-RCs were washed with a low salt buffer (lanes 7–9, 11, 12, 14 and 15) or a high salt buffer (lanes 10, 13 and 16).