AcrA suppressor alterations reverse the drug hypersensitivity phenotype of a TolC mutant by inducing TolC aperture opening.
AcrA suppressor alterations reverse the drug hypersensitivity phenotype of a TolC mutant by inducing TolC aperture opening.
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DOI：
10.1111/j.1365-2958.2010.07068.x
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发表时间：
2010-03
影响因子：
3.6
通讯作者：
Misra R
中科院分区：
文献类型：
--
作者：
Weeks JW;Celaya-Kolb T;Pecora S;Misra R
在大肠杆菌中，TolC-AcrAB复合物形成具有广泛底物特异性的主要抗生素外排系统。在复合物组装过程中，TolC的周质螺旋和底部转角被认为分别与AcrA的发夹螺旋和AcrB的发夹环相互作用。在本研究中，我们表明，四个残基取代TolC的转1，连接外螺旋3和4近端TolC的周质孔，赋予抗生素超敏反应，而不影响TolC介导的噬菌体或大肠杆菌素感染。然而，尽管空样药物敏感性表型，化学交联分析显示，突变体TolC蛋白与AcrA和AcrB物理相互作用的能力没有明显的缺陷。TolC转1残基在三方外排泵复合物的功能组装中的作用通过分离突变体TolC蛋白的抑制突变和利用不稳定的AcrA蛋白来揭示，所述突变体TolC蛋白在acrA内映射。数据显示，AcrA介导的抗生素敏感性抑制是通过以AcrB依赖性方式扩张TolC孔/通道来实现的。这些结果强调了TolC的周质转1在三方外排复合物的功能组装中的重要性，并且AcrA在将TolC从其关闭状态转变为开放状态中。
In Escherichia coli, the TolC–AcrAB complex forms a major antibiotic efflux system with broad substrate specificity. During the complex assembly, the periplasmic helices and bottom turns of TolC are thought to interact with a hairpin helix of AcrA and hairpin loops of AcrB respectively. In the present study we show that a four-residue substitution in TolC’s turn 1, which connects outer helices 3 and 4 proximal to TolC’s periplasmic aperture, confers antibiotic hypersensitivity without affecting TolC-mediated phage or colicin infection. However, despite the null-like drug sensitivity phenotype, chemical cross-linking analysis revealed no apparent defects in the ability of the mutant TolC protein to physically interact with AcrA and AcrB. A role for TolC turn 1 residues in the functional assembly of the tripartite efflux pump complex was uncovered through isolating suppressor mutations of the mutant TolC protein that mapped within acrA and by utilizing a labile AcrA protein. The data showed that AcrA-mediated suppression of antibiotic sensitivity was achieved by dilating the TolC aperture/channel in an AcrB-dependent manner. The results underscore the importance of the periplasmic turn 1 of TolC in the functional assembly of the tripartite efflux complex and AcrA in transitioning TolC from its closed to open state.
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影响因子：
3.6
作者：
Colmer, JA;Fralick, JA;Hamood, AN
通讯作者：
Hamood, AN
影响因子：
3.2
作者：
Elkins, CA;Nikaido, H
通讯作者：
Nikaido, H
DOI：
10.1073/pnas.0610160104
发表时间：
2007-03-13
影响因子：
11.1
作者：
Lobedanz, Sune;Bokma, Evert;Koronakis, Vassilis
通讯作者：
Koronakis, Vassilis
影响因子：
16
作者：
Bavro, Vassiliy N.;Pietras, Zbigniew;Furnham, Nicholas;Perez-Cano, Laura;Fernandez-Recio, Juan;Pei, Xue Yuan;Misra, Rajeev;Luisi, Ben
通讯作者：
Luisi, Ben
影响因子：
3.2
作者：
CHANG, ACY;COHEN, SN
通讯作者：
COHEN, SN