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. 2009 Sep 26;37(21):7219–7230. doi: 10.1093/nar/gkp794

Figure 4.

Figure 4.

LlaGI produces transient changes in DNA supercoiling consistent with loop translocase activity. (A) Schematic of the topoisomerase assay (48). DNA and enzyme shown as in previous figures. See main text for further details. (B) The four different starting substrates for the topology assay derived from pRMA03 and pRMA03F (‘Materials and Methods’ section). 0s is zero-site supercoiled, 0r is zero-site relaxed, 1s is one-site supercoiled and 1r is one-site relaxed. (C) LlaGIDA078, a nuclease mutant of LlaGI (38), was used to prevent DNA cleavage. Reactions contained 10 nM DNA and, as indicated, 4 mM ATP, 5 U E. coli topoisomerase I (E), 10 U wheat germ topoisomerase I (W) and/or 50 nM LlaGIDA078. Reactions were incubated for 30 min at 37°C and separated by agarose gel electrophoresis.