Plays an important role in DNA replication, recombination and repair. Binds to ssDNA and to an array of partner proteins to recruit them to their sites of action during DNA metabolism (By similarity). Essential for ionizing radiation resistance. Stimulates the 5'-3' DNA helicase activity of RecD-like helicase. Stimulates RecA protein-promoted DNA three-strand exchange reactions in vitro with both D.radiodurans and E.coli-derived RecA. Complements an ssb deletion in E.coli, but does not complement a ddrb disruption in D.radiodurans. Homodimer. Binds ssDNA. Interacts with DdrB. During log phase, present in multiple foci. 1 hour after irradiation most foci are condensed in the center of the cell's nucleoid, they dissipate by 2 hours later. Constitutively expressed, highly up-regulated following ionizing radiation for at least 12 hours (at protein level). Essential, it cannot be knocked out. As SSB levels are depleted growth slows, tolerance to ionizing radiation and UV light decreases rapidly. Cannot be complemented by ddrB.