AcrA, AcrB, and TolC of Escherichia coli form a stable intermembrane multidrug efflux complex

被引:202
作者
Tikhonova, EB [1 ]
Zgurskaya, HI [1 ]
机构
[1] Univ Oklahoma, Dept Chem & Biochem, Norman, OK 73019 USA
关键词
D O I
10.1074/jbc.M402230200
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Many transporters of Gram-negative bacteria involved in the extracellular secretion of proteins and the efflux of toxic molecules operate by forming intermembrane complexes. These complexes are proposed to span both inner and outer membranes and create a bridge across the periplasm. In this study, we analyzed interactions between the inner and outer membrane components of the tri-partite multidrug efflux pump AcrAB-TolC from Escherichia coli. We found that, once assembled, the intermembrane AcrAB-TolC complex is stable during the separation of the inner and outer membranes and subsequent purification. All three components of the complex co-purify when the affinity tag is attached to either of the proteins suggesting bi-partite interactions between AcrA, AcrB, and TolC. We show that antibiotics, the substrates of AcrAB-TolC, stabilize interactions within the complex. However, the formation of the AcrAB-TolC complex does not require an input of energy.
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页码:32116 / 32124
页数:9
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