MOLECULAR-GENETICS AND TRANSPORT ANALYSIS OF THE COPPER-RESISTANCE DETERMINANT (PCO) FROM ESCHERICHIA-COLI PLASMID PRJ1004
MOLECULAR-GENETICS AND TRANSPORT ANALYSIS OF THE COPPER-RESISTANCE DETERMINANT (PCO) FROM ESCHERICHIA-COLI PLASMID PRJ1004
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DOI：
10.1111/j.1365-2958.1995.mmi_17061153.x
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发表时间：
1995-09-01
影响因子：
3.6
通讯作者：
ROUCH, DA
中科院分区：
文献类型：
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作者：
BROWN, NL;BARRETT, SR;ROUCH, DA
对大肠杆菌质粒pRJ 1004的铜抗性决定簇（pco）基因进行了克隆和序列测定。Tn 1000转座子诱变确定了四个互补组，其中任何一个突变消除铜抗性。DNA序列分析表明，4个互补组含有6个开放阅读框，命名为pco-ABCDRS。由该核苷酸序列衍生的蛋白产物序列显示该铜抗性系统与假单胞菌致病变种的质粒pPT 23 D的cop系统之间具有密切的同源性。番茄PcoR和PcoS蛋白序列显示出与双组分传感器/应答器磷酸激酶调节系统家族的同源性。第七个阅读框（pcoE）从DNA序列数据中鉴定，并位于铜调控启动子的下游。运输试验与Cu-64（II）表明，含有质粒的耐药细胞在对数生长期铜积累减少，而增加积累以前已观察到在稳定期。获得了细胞铜管理缺陷的染色体突变体并进行了表征。在这些突变体中的两个，pco抗性呈现完全失活，而在另外两个突变体pco补充缺陷基因。这些数据表明，质粒携带的铜抗性在大肠杆菌。大肠杆菌与铜管理的染色体系统相连。
The copper-resistance determinant (pco) of Escherichia coli plasmid pRJ1004 was cloned and sequenced. Tn1000 transposon mutagenesis identified four complementation groups, mutations in any of which eliminated copper resistance. DNA sequence analysis showed that the four complementation groups contained six open reading frames, designated pco-ABCDRS. The protein product sequences derived from the nucleotide sequence show close homology between this copper-resistance system and the cop system of a plasmid pPT23D of Pseudomonas syringae pv. tomato. The PcoR and PcoS protein sequences show homology to the family of two-component sensor/responder phosphokinase regulatory systems. A seventh reading frame (pcoE) was identified from DNA sequence data, and lies downstream of a copper-regulated promoter. Transport assays with Cu-64(II) showed that the resistant cells containing the plasmid had reduced copper accumulation during the log phase of growth, while increased accumulation had previously been observed during stationary phase. Chromosomal mutants defective in cellular copper management were obtained and characterized. In two of these mutants pco resistance was rendered totally inactive, whilst in another two mutants pco complemented the defective genes. These data indicate that plasmid-borne copper resistance in E. coli is linked with chromosomal systems for copper management.