Browsing by Author "Chenail, Alicia M."
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- BpaB, a novel protein encoded by the Lyme disease spirochete’s cp32 prophages, binds to erp Operator 2 DNABurns, Logan H.; Adams, Claire A.; Riley, Sean P.; Jutras, Brandon L.; Bowman, Amy; Chenail, Alicia M.; Cooley, Anne E.; Haselhorst, Laura A.; Moore, Alisha M.; Babb, Kelly; Fried, Michael G.; Stevenson, Brian (Oxford University Press, 2010)Borrelia burgdorferi produces Erp outer surface proteins throughout mammalian infection, but represses their synthesis during colonization of vector ticks. A DNA region 50 of the start of erp transcription, Operator 2, was previously shown to be essential for regulation of expression. We now report identification and characterization of a novel erp Operator 2-binding protein, which we named BpaB. erp operons are located on episomal cp32 prophages, and a single bacterium may contain as many as 10 different cp32s. Each cp32 family member encodes a unique BpaB protein, yet the three tested cp32-encoded BpaB alleles all bound to the same DNA sequence. A 20-bp region of erp Operator 2 was determined to be essential for BpaB binding, and initial protein binding to that site was required for binding of additional BpaB molecules. A 36-residue region near the BpaB carboxy terminus was found to be essential for high-affinity DNA-binding. BpaB competed for binding to erp Operator 2 with a second B. burgdorferi DNAbinding protein, EbfC. Thus, cellular levels of free BpaB and EbfC could potentially control erp transcription levels.
- Eubacterial SpoVG Homologs Constitute a New Family of Site-Specific DNA-Binding ProteinsJutras, Brandon L.; Chenail, Alicia M.; Rowland, Christi L.; Carroll, Dustin W.; Miller, M. Clarke; Bykowski, Tomasz; Stevenson, Brian (PLOS, 2013-06-20)A site-specific DNA-binding protein was purified from Borrelia burgdorferi cytoplasmic extracts, and determined to be a member of the highly conserved SpoVG family. This is the first time a function has been attributed to any of these ubiquitous bacterial proteins. Further investigations into SpoVG orthologues indicated that the Staphylococcus aureus protein also binds DNA, but interacts preferentially with a distinct nucleic acid sequence. Site-directed mutagenesis and domain swapping between the S. aureus and B. burgdorferi proteins identified that a 6-residue stretch of the SpoVG a-helix contributes to DNA sequence specificity. Two additional, highly conserved amino acid residues on an adjacent b-sheet are essential for DNA-binding, apparently by contacts with the DNA phosphate backbone. Results of these studies thus identified a novel family of bacterial DNA-binding proteins, developed a model of SpoVG-DNA interactions, and provide direction for future functional studies on these wide-spread proteins.