Disruption of the Borrelia burgdorferi gac gene, encoding the naturally synthesized GyrA C-terminal domain

The C-terminal domain of the A subunit of DNA gyrase, which we term Gac, is naturally synthesized in Borrelia burgdorferi as an abundant DNA-binding p rotein. Full-length GyrA, which includes the C-terminal domain, is also syn thesized by the spirochete and functions as a subunit of DNA gyrase, We hav e disrupted synthesis of Gac as an independent protein and demonstrated tha t it is not essential for growth in a coumarin-resistant background. We det ected no alterations in DNA maintenance, condensation, or topology In B. bu rgdorferi lacking this small DNA-binding protein.