Purification and characterization of a metal‐dependent regulator protein from Thermobifida fusca

Iron dependent regulators are proteins found in a variety of pathogenic bacteria that cause diseases such as tuberculosis and diphtheria. We recently characterized a crudely purified metal‐dependent regulator from Thermobifida fusca, and demonstrated binding to the DtxR tox operator consensus sequence. The regulator from T. fusca has a longer N‐terminal helix than homologs such as DtxR. Conformational changes have been shown to occur upon metal binding in homologous proteins, and it has been suggested that this helix is important in metal and DNA binding. We have now purified the protein to greater than 90% purity as judged by SDS‐PAGE, and also report the Tf‐IdeR protein binds the EntS operator sequence from its own genome. Additionally, computational analysis of the N‐terminus indicates Ile7 may be important for metal‐dependent DNA binding. This research is supported by the Wabash College Haines Biochemistry Fund.