The Lyme disease spirochete, Borrelia burgdorferi, encodes a novel type of DNA-binding protein named EbfC. Orthologs of EbfC are encoded by a wide range of bacterial species, so characterization of the borrelial protein has implications that span the eubacterial kingdom. The present work defines the DNA sequence required for high-affinity binding by EbfC to be the 4 bp broken palindrome GTnAC, where ‘n’ can be any nucleotide. Two high-affinity EbfC-binding sites are located immediately 5′ of B. burgdorferi erp transcriptional promoters, and binding of EbfC was found to alter the conformation of erp promoter DNA. Consensus EbfC-binding sites are abundantly distributed throughout the B. burgdorferi genome, occurring approximately once every 1 kb. These and other features of EbfC suggest that this small protein and its orthologs may represent a distinctive type of bacterial nucleoid-associated protein. EbfC was shown to bind DNA as a homodimer, and site-directed mutagenesis studies indicated that EbfC and its orthologs appear to bind DNA via a novel α-helical ‘tweezer’-like structure.
Digital Object Identifier (DOI)
Riley, Sean P.; Bykowski, Tomasz; Cooley, Anne E.; Burns, Logan H.; Babb, Kelly; Brissette, Catherine A.; Bowman, Amy; Rotondi, Matthew L.; Miller, M. Clarke; Demoll, Edward; Lim, Kap; Fried, Michael G.; and Stevenson, Brian, "Borrelia burgdorferi EbfC Defines a Newly-Identified, Widespread Family of Bacterial DNA-Binding Proteins" (2009). Microbiology, Immunology, and Molecular Genetics Faculty Publications. 42.