Figure 4.

Cleavage selectivity of topoisomerase I and Top67. This was analyzed using single-stranded 32mer (a), 31mer (b), or substrate with both single- and double-stranded regions (c). For (a) and (b), lane 1: no protein added, lane 2: topoisomerase I, lane 3: Top67, lane 4: Top67 mixed with ZD. For (a), lane 5: ZD alone. For (c), lane 1: topoiosmerase I, lane 2: Top67, lane 3: no protein added, lane 4: DNase I digestion pattern.