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.
|Number of pages||11|
|Journal||Nucleic Acids Research|
|State||Published - 2009|
Bibliographical noteFunding Information:
US National Institutes of Health (grant R01-AI044254 to B.S. and R01-GM070662 to M.F.); National Institutes of Health Training Grant in Microbial Pathogenesis T32-AI49795 (to S.R.); University of Kentucky Graduate School Dissertation Year Fellowship (to S.R.). Funding for open access charge: US National Institutes of Health (grant R01-AI044254).
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