Figure 5.

Q607 is required for stable ROS1 binding to substrate and product DNA. Purified WT ROS1 or mutant variant Q607A (100 nM) were incubated with a mixture of 100 nM fluorescein-labeled 5-meC:G substrate and 100 nM alexa-labeled 1-nt gapped product, and the reactions were monitored for 60 min. After non-denaturing gel electrophoresis, the gel was scanned to detect fluorescein- (upper panel) or alexa-labeled (lower panel) DNA. Protein–DNA complexes were identified by their retarded mobility compared with that of free DNA, as indicated. The asterisk depicts 5′-end labeling of the upper strand. M: 5-meC.