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The bacterial RadD enzyme is important for multiple genome maintenance pathways, including RecA DNA strand exchange and RecA-independent suppression of DNA crossover template switching. However, much remains unknown about the precise roles of RadD. One potential clue into RadD mechanisms is its direct interaction with the single-stranded DNA binding protein (SSB), which coats single-stranded DNA exposed during genome maintenance reactions in cells. Interaction with SSB stimulates the ATPase activity of RadD. To probe the mechanism and importance of RadD/SSB complex formation, we identified a pocket on RadD that is essential for binding SSB. In a mechanism shared with many other SSB-interacting proteins, RadD uses a hydrophobic pocket framed by basic residues to bind the C-terminal end of SSB. RadD variants that substitute acidic residues for basic residues in the SSB binding site impair RadD/SSB complex formation and eliminate SSB stimulation of RadD ATPase activityin vitro. MutantE. colistrains carrying charge reversalradDchanges display increased sensitivity to DNA damaging agents synergistically with deletions ofradAandrecG, although the phenotypes of the SSB-bindingradDmutants are not as severe a fullradDdeletion. This suggests that RadD has multiple functions in the cell, with a subset requiring the interaction with SSB.