EMR, AN ESCHERICHIA-COLI LOCUS FOR MULTIDRUG RESISTANCE
EMR, AN ESCHERICHIA-COLI LOCUS FOR MULTIDRUG RESISTANCE
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DOI：
10.1073/pnas.89.19.8938
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发表时间：
1992-10-01
影响因子：
11.1
通讯作者：
LEWIS, K
中科院分区：
文献类型：
--
作者：
LOMOVSKAYA, O;LEWIS, K
克隆在多拷贝质粒上的大肠杆菌染色体 DNA 片段赋予了对羰基氰间氯苯腙、萘啶酸和许多其他有毒化合物的抗性。位于染色体第 57.5 分钟的克隆 emr 基因座的序列显示出两个开放阅读框：emrA 和 emrB。 emrB 编码高度疏水性的 56.2-kDa 肽，具有 14 个潜在的 α 螺旋跨越内膜。该肽与 QacA（金黄色葡萄球菌的一种多重耐药泵）同源，属于一个基因家族，其中包括革兰氏阳性菌的四环素耐药泵和大肠杆菌的半乳糖/H+ 同向转运蛋白。 emrA 编码一个推定的 42.7-kDa 肽，包含一个疏水结构域和一个大的 C 端亲水结构域。与 C 结构域的主动 pho 融合表明 EmrA 是一种膜蛋白。 emrB 的破坏显着增加了细胞对解偶联剂的敏感性。解偶联剂的细胞含量按以下顺序增加：过表达的emrB细胞>野生型>emrB-。
An Escherichia coli chromosomal DNA fragment cloned on a multicopy plasmid conferred resistance to carbonylcyanide m-chlorophenylhydrazone, nalidixic acid, and a number of other toxic compounds. The sequence of the cloned emr locus located at minute 57.5 of the chromosome revealed two open reading frames, emrA and emrB. emrB encodes a highly hydrophobic 56.2-kDa peptide, with 14 potential alpha-helices to span the inner membrane. The peptide is homologous to QacA, a multidrug-resistant pump from Staphylococcus aureus, and belongs to a gene family that includes tetracycline-resistant pumps of Gram-positive bacteria and the galactose/H+ symporter of E. coli. emrA encodes a putative 42.7-kDa peptide containing a single hydrophobic domain and a large C-terminal hydrophilic domain. An active pho-fusion to the C domain suggested that EmrA is a membrane protein. Disruption of emrB significantly increased sensitivity of cells to uncouplers. The cellular content of uncoupler increased in the order: overexpressed emrB cells > wild type > emrB-.