Riley Sean P, Bykowski Tomasz, Cooley Anne E, Burns Logan H, Babb Kelly, Brissette Catherine A, Bowman Amy, Rotondi Matthew, Miller M Clarke, DeMoll Edward, Lim Kap, Fried Michael G, Stevenson Brian
Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536-0298, USA.
Nucleic Acids Res. 2009 Apr;37(6):1973-83. doi: 10.1093/nar/gkp027. Epub 2009 Feb 10.
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 alpha-helical 'tweezer'-like structure.
莱姆病螺旋体，伯氏疏螺旋体，编码一种名为EbfC的新型DNA结合蛋白。EbfC的直系同源物由多种细菌物种编码，因此对伯氏疏螺旋体蛋白的表征具有跨越真细菌界的意义。目前的工作确定EbfC高亲和力结合所需的DNA序列为4 bp的断裂回文序列GTnAC，其中“n”可以是任何核苷酸。两个高亲和力的EbfC结合位点位于伯氏疏螺旋体erp转录启动子的紧邻5'端，并且发现EbfC的结合会改变erp启动子DNA的构象。一致的EbfC结合位点在伯氏疏螺旋体基因组中大量分布，大约每1 kb出现一次。EbfC的这些和其他特征表明，这种小蛋白及其直系同源物可能代表一种独特类型的细菌类核相关蛋白。EbfC被证明以同源二聚体形式结合DNA，定点诱变研究表明，EbfC及其直系同源物似乎通过一种新型的α螺旋“镊子”样结构结合DNA。
