Borrelia burgdorferi produces Erp outer surface proteins throughout mammalian infection, but represses their synthesis during colonization of vector ticks. A DNA region 5′ 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 DNA-binding protein, EbfC. Thus, cellular levels of free BpaB and EbfC could potentially control erp transcription levels.
Digital Object Identifier (DOI)
Burns, 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.; and Stevenson, Brian, "BpaB, a Novel Protein Encoded by the Lyme Disease Spirochete's Cp32 Prophages, Binds to Erp Operator 2 DNA" (2010). Microbiology, Immunology, and Molecular Genetics Faculty Publications. 40.