FIG. 4.

Proposed mechanism of RuvB/RecG Holliday junction resolution in H. pylori. Our results suggest that two H. pylori DNA processing pathways may compete for the same intermediate, a Holliday junction, which can be branch migrated (left pathway) by RuvAB and resolved by RuvC, leading to restoration of an intact replication fork, enabling loading of the replisome (small oval). Alternatively, (middle pathway) RecG (gray circle) can branch migrate Holliday junctions, but due to lack of resolution, there is no restoration of template leading to cell death. Addition of RusA restores the RecG pathway, leading to recombinational repair. RecG may act upstream of RuvABC to directly convert stalled forks into Holliday junctions in H. pylori, as it does in E. coli. Although this has not yet been shown to occur in H. pylori, this is depicted as a possibility.