Figure 2.

Trans activation of Int^Cat by Int^CB. DNA cleavage activity monitored by denaturing SDS-PAGE analysis of the formation of a covalent complex between the protein and a 5’-radiolabeled DNA suicide substrate. Lane 1, the catalytic domain alone (Int^Cat); lane 2, the catalytic domain in the presence of the (separately added) core-binding domain (Int^Cat + Int^CB); lane 3, the linked core and catalytic domains in the context of Int^CB+Cat (lane 3). The concentration of the DNA substrate was 0.1 μM, while the Int^Cat, Int^CB and Int^CB+Cat concentrations were 4 μM. Addition of Int^CB results in a large increase in complex formation, while linking the two domains provides an additional enhancement.