FIG. 6.

Potassium permanganate reactivity in the ori caused by binding of E1. A top-strand ori probe was incubated in the absence (−) or presence of increasing quantities of E1 protein (15, 30, and 60 ng). As a control, 60 ng of E1 was incubated in the presence of 5 mM ATP (+ATP). After 20 min at room temperature, potassium permanganate was added to 6 mM, and the reaction was terminated after 2 min by addition of 2-mercaptoethanol. After cleavage with piperidine, the resulting material was analyzed by 10% polyacrylamide gel electrophoresis. The positions of permanganate reactivity are indicated by arrows. Below, these positions are indicated in relation to the boxed E1 and E2 BS.