Identification of the Preferred DNA-Binding Sequence and Transcription Regulatory Network for the Thermophilic Zinc Uptake Regulator TTHA1292.

D-block metal cations are essential for most biological processes; however, excessive metal exposure can be deleterious to the survival of microorganisms. To tightly control heavy metal regulation, prokaryotic organisms have developed several mechanisms to sense and adapt to changes in intracellular and extracellular metal concentrations. The ferric uptake regulator superfamily of transcription factors associates with DNA when complexed with a regulatory metal cofactor and often represses the transcription of genes involved in metal transport, thus providing a genomic response to an environmental stressor. Although extensively studied in mesothermic organisms, there is little information describing ferric uptake regulator homologs in thermophiles. In this study, we biochemically characterize the ferric uptake regulator homolog TTHA1292 in the extreme thermophile Thermus thermophilus HB8. We identify the preferred DNA-binding sequence of TTHA1292 using the combinatorial approach, restriction endonuclease, protection, selection, and amplification (REPSA). We map this sequence to the Thermus thermophilus HB8 genome and identify the TTHA1292 transcription regulatory network, which includes the zinc ABC transporter subunit genes