CLONING AND DNA-SEQUENCE OF THE MERCURIC-RESISTANCE AND ORGANOMERCURIAL-RESISTANCE DETERMINANTS OF PLASMID PDU1358
CLONING AND DNA-SEQUENCE OF THE MERCURIC-RESISTANCE AND ORGANOMERCURIAL-RESISTANCE DETERMINANTS OF PLASMID PDU1358
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DOI：
10.1073/pnas.84.10.3112
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发表时间：
1987-05-01
影响因子：
11.1
通讯作者：
MISRA, TK
中科院分区：
文献类型：
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作者：
GRIFFIN, HG;FOSTER, TJ;MISRA, TK
通过克隆抗性决定簇并制备质粒的45-kb区域的物理和遗传图谱来分析广谱汞抗性质粒pDU 1358，所述质粒含有两个分开的汞抗性操纵子，所述操纵子相距约20 kb。一个编码窄谱汞电阻汞2+和一些有机汞;其他指定的广谱电阻苯汞和其他有机汞。每个决定因素支配着汞的运输功能。使用来自质粒R100 mer操纵子的基因特异性探针的Southern DNA-DNA杂交实验表明与R100决定子具有密切的同源性。对pDU 1358的广谱抗汞操纵子的启动子远端部分的2153个碱基对进行测序。该区域包括merA基因的3“-末端部分、merD、未鉴定的阅读框URF 1和与先前测序的质粒R100决定簇同源的URF 2的一部分。在merA和merD基因之间，一个编码212个氨基酸多肽的开放阅读框被鉴定为merB基因，该基因决定了切割苯汞的C-Hg键的有机汞裂解酶。
The broad-spectrum mercurial-resistance plasmid pDU1358 was analyzed by cloning the resistance determinants and preparing physical and genetic map of a 45-kilobase (kb) region of the plasmid that contains two separate mercurial-resistance operons that mapped about 20 kb apart. One encoded narrow-spectrum mercurial resistance to Hg2+ and a few organomercurials; the other specified broad-spectrum resistance to phenylmercury and additional organomercurials. Each determinant governed mercurial transport functions. Southern DNA.cntdot.DNA hybridization experiments using gene-specific probes from the plasmid R100 mer operon indicated close homolgy with the R100 determinant. The 2153 base pairs of the promoter-distal part of the broad-spectrum Hg2+-resistance operon of pDU1358 were sequenced. This region included the 3''-terminal part of the merA gene, merD, unidentified reading frame URF1, and a part of URF2 homologous to previously sequenced determinants of plasmid R100. Between the merA and merD genes, an open reading frame encoding a 212 amino acid polypeptide was identified as the merB gene that determines the enzyme organomercurial lyase that cleaves the C-Hg bond of phenylmercury.