Department of Chemistry and Biochemistry, Kennesaw State Universitygrid.258509.3, Kennesaw, Georgia, USA.
J Bacteriol. 2022 Nov 15;204(11):e0030322. doi: 10.1128/jb.00303-22. Epub 2022 Oct 26.
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 and . We formally implicate TTHA1292 as a zinc uptake regulator and show that zinc coordination is critical for the multimerization of TTHA1292 dimers on DNA and transcription repression . Discovering how organisms sense and adapt to their environments is paramount to understanding biology. Thermophilic organisms have adapted to survive at elevated temperatures (>50°C); however, our understanding of how these organisms adapt to changes in their environment is limited. In this study, we identify a zinc uptake regulator in the extreme thermophile Thermus thermophilus HB8 that provides a genomic response to fluctuations in zinc availability. These results provide insights into thermophile biology, as well as the zinc uptake regulator family of proteins.
D 族金属阳离子是大多数生物过程所必需的；然而，过量的金属暴露会对微生物的生存造成有害影响。为了严格控制重金属的调节，原核生物已经开发出几种机制来感知和适应细胞内和细胞外金属浓度的变化。铁摄取调节因子超家族转录因子与 DNA 结合，当与调节金属辅因子复合时，通常会抑制与金属转运相关的基因的转录，从而为环境应激提供基因组反应。尽管在中温生物中得到了广泛研究，但关于嗜热菌中铁摄取调节因子同源物的信息却很少。在这项研究中，我们对极端嗜热菌 Thermus thermophilus HB8 中的铁摄取调节因子同源物 TTHA1292 进行了生化表征。我们使用组合方法、限制性内切酶、保护、选择和扩增 (REPSA) 来确定 TTHA1292 的首选 DNA 结合序列。我们将该序列映射到 Thermus thermophilus HB8 基因组上，并确定了 TTHA1292 的转录调控网络，该网络包括锌 ABC 转运体亚基基因 和 。我们正式将 TTHA1292 确定为锌摄取调节剂，并表明锌配位对于 TTHA1292 二聚体在 DNA 上的多聚化 和转录抑制 至关重要。了解生物体如何感知和适应环境对于理解生物学至关重要。嗜热生物已经适应了高温 (>50°C) 的生存；然而，我们对这些生物体如何适应环境变化的理解是有限的。在这项研究中，我们在极端嗜热菌 Thermus thermophilus HB8 中鉴定出一种锌摄取调节剂，它为锌供应波动提供了基因组反应。这些结果为嗜热生物生物学以及锌摄取调节蛋白家族提供了新的见解。
