BTR ELISA Kits

A study investigated the mechanism of transcription activation by B. subtilis Bt, an unusual member of the AraC family of transcription factors. Biochemical studies of AraC family activators are often challenging, due to the difficulties with both over-expression and purification. As a result, only a handful of AraC family proteins have been biochemically characterized. Btr contains an amino-terminal DNA-binding and dimerization domain appended to a carboxy-terminal ligand-binding domain structurally and functionally related to siderophore substrate binding proteins associated with iron import. Btr binds upstream of the promoter for the feuABC operon (PfeuA) encoding an ABC transporter for the import of ferric-bacillibactin (BB), a catecholate siderophore made by various Bacillus spp. In the presence of BB (and to a lesser extent, de-ferrated BB), the Btr:BB complex strongly activates transcription from PfeuA. The mechanism of activation has shown prominently a large and ligand-activated increase in the formation of productive transcripts due to an increase in the rate of promoter escape.

Bordetella pertussis is the causative agent of the respiratory disease pertussis. Btr, an oxygen-responsive transcriptional regulator of B. pertussis, is homologous to the FNR protein of E. coli. Using a murine respiratory model, a study observed that Btr is important in growth and survival of B. pertussis in vivo. A titration assay was developed that identified genes containing Btr binding sites including B. pertussis sodB and btr, E. coli aspA and a new B. pertussis gene, brg1. The brg1 gene encodes a protein similar to the LysR family of transcriptional regulators, and its expression is activated threefold by Btr under anaerobic growth conditions but unaffected by Btr aerobically.