Copper Acquisition Is Mediated by YcnJ and Regulated by YcnK and CsoR in Bacillus subtilis
Copper Acquisition Is Mediated by YcnJ and Regulated by YcnK and CsoR in Bacillus subtilis
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DOI：
10.1128/jb.01616-08
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发表时间：
2009-04-01
影响因子：
3.2
通讯作者：
Marahiel, Mohamed A.
中科院分区：
文献类型：
--
作者：
Chillappagari, Shashi;Miethke, Marcus;Marahiel, Mohamed A.
铜是许多酶的重要辅因子，超过临界值时，它对所有生物体都是有毒的。为了了解革兰氏阳性细菌枯草芽孢杆菌铜稳态的机制，我们在铜限制条件下进行了微阵列研究。这些研究表明，ycnJ基因编码一种在铜代谢中发挥重要作用的蛋白质，因为它在铜限制条件下显著上调8倍，它的中断会导致铜缺乏时生长缺陷的表型，以及细胞内铜含量的降低。YcnJ膜蛋白(135个残基)的N-末端结构域的天然凝胶移动实验表明，它在体外与铜(II)离子有很强的亲和力。对ycnJ上游序列的检测表明，ycnK基因编码一个可能的转录调节因子，该调控因子的缺失导致ycnJ的表达上调，特别是在铜过量的情况下。进一步的研究表明，最近发现的铜外排调节因子CSOR也参与了ycnJ的表达调控，为枯草杆菌铜的动态平衡提供了一个新的模型。
Copper is an essential cofactor for many enzymes, and at over a threshold level, it is toxic for all organisms. To understand the mechanisms underlying copper homeostasis of the gram-positive bacterium Bacillus subtilis, we have performed microarray studies under copper-limiting conditions. These studies revealed that the ycnJ gene encodes a protein that plays an important role in copper metabolism, as it shows a significant, eightfold upregulation under copper-limiting conditions and its disruption causes a growth-defective phenotype under copper deprivation as well as a reduced intracellular content of copper. Native gel shift experiments with the periplasmic N-terminal domain of the YcnJ membrane protein (135 residues) disclosed its strong affinity to Cu(II) ions in vitro. Inspection of the upstream sequence of ycnJ revealed that the ycnK gene encodes a putative transcriptional regulator, whose deletion caused an elevated expression of ycnJ, especially under conditions of copper excess. Further studies demonstrated that the recently identified copper efflux regulator CsoR also is involved in the regulation of ycnJ expression, leading to a new model for copper homeostasis in B. subtilis.