Molecular characterization of a conserved archaeal copper resistance (cop) gene cluster and its copper-responsive regulator in Sulfolobus solfataricus P2
Molecular characterization of a conserved archaeal copper resistance (cop) gene cluster and its copper-responsive regulator in Sulfolobus solfataricus P2
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DOI：
10.1099/mic.0.28724-0
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发表时间：
2006-07-01
期刊：
影响因子：
2.8
通讯作者：
van der Oost, John
中科院分区：
文献类型：
--
作者：
Ettema, Thijs J. G.;Brinkman, Arie B.;van der Oost, John
利用比较基因组学方法，在多个古菌基因组中发现了一个抗铜基因簇。据预测，COP簇编码一个金属配位蛋白(CopM)、一个P型铜输出ATPase(COPA)和一个可能控制COP基因表达的新的古生菌特异性转录调节因子(COPT)。序列分析表明，COPT有一个N端DNA结合的螺旋-转角-螺旋结构域和一个C-末端的Trash结构域；Trash是一个新的结构域，最近被发现与原核生物中的传感器、转运蛋白和运输蛋白中的金属结合有关。本研究描述了嗜热嗜酸菌Sulfolobus solafaricus中COP基因簇的分子特征。多顺反子COPMA转录本被发现对生长抑制铜浓度的反应而积累，而COPT转录本的丰度似乎是结构性的。DNA结合分析表明，COPT与COPMA启动子在多个位置结合，包括预测的TATA-BRE位点的上游和下游。铜被发现特异性地调节COPT与DNA结合的亲和力。这项研究描述了古生菌中一个铜反应操纵子，这是一个新的古生菌DNA结合蛋白家族，并支持该结构域在古生菌铜反应中发挥重要作用的观点。提出了铜响应COPMA基因簇转录调控的模型。
Using a comparative genomics approach, a copper resistance gene cluster has been identified in multiple archaeal genomes. The cop cluster is predicted to encode a metallochaperone (CopM), a P-type copper-exporting ATPase (CopA) and a novel, archaea-specific transcriptional regulator (CopT) which might control the expression of the cop genes. Sequence analysis revealed that CopT has an N-terminal DNA-binding helix-turn-helix domain and a C-terminal TRASH domain; TRASH is a novel domain which has recently been proposed to be uniquely involved in metal-binding in sensors, transporters and trafficking proteins in prokaryotes. The present study describes the molecular characterization of the cop gene cluster in the thermoacidophilic crenarchaeon Sulfolobus solfataricus. The polycistronic copMA transcript was found to accumulate in response to growth-inhibiting copper concentrations, whereas copT transcript abundance appeared to be constitutive. DNA-binding assays revealed that CopT binds to the copMA promoter at multiple sites, both upstream and downstream of the predicted TATA-BRE site. Copper was found to specifically modulate the affinity of DNA binding by CopT. This study describes a copper-responsive operon in archaea, a new family of archaeal DNA-binding proteins, and supports the idea that this domain plays a prominent role in the archaeal copper response. A model is proposed for copper-responsive transcriptional regulation of the copMA gene cluster.