Structural basis for the inhibition of bacterial multidrug exporters
Structural basis for the inhibition of bacterial multidrug exporters
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DOI：
10.1038/nature12300
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发表时间：
2013-08-01
期刊：
影响因子：
64.8
通讯作者：
Yamaguchi, Akihito
中科院分区：
文献类型：
--
作者：
Nakashima, Ryosuke;Sakurai, Keisuke;Yamaguchi, Akihito
多药外排转运蛋白AcrB及其同系物在革兰氏阴性菌(1，2)多药耐药中起重要作用。然而，尽管努力开发外排抑制剂(3)，但目前还没有临床上有用的抑制剂(4，5)。吡啶并嘧啶类化合物是AcrB和MexB特异性的抑制剂，不抑制MexY(6，7)；MexB和MexY是铜绿假单胞菌(8-10)的主要多药输出体。我们以前已经测定了AcrB在没有和存在抗生素的情况下的晶体结构(11-13)。显示药物通过串联的近端和远端多部位药物结合袋(13)通过功能旋转机构(12)输出。在这里，我们描述了AcrB和MexB的第一个抑制剂结合结构，在这些结构中，这些蛋白质被吡啶并嘧啶衍生物结合。吡啶类化合物与位于远端口袋的由苯丙氨酸簇组成的狭窄凹坑紧密结合，并在空间上阻碍功能旋转。这个凹坑是一个疏水陷阱，从底物易位通道分支出来。Phe 178位于AcrB和MexB的这个陷阱的边缘，通过pi-pi与吡啶并嘧啶环的相互作用促进了抑制剂分子的紧密结合。位于MexY相应位置的Trp 177的庞大侧链阻止了抑制剂的结合。本研究中所描述的疏水陷阱的结构将有助于开发铜绿假单胞菌MexB和MexY的通用抑制剂。
The multidrug efflux transporter AcrB and its homologues are important in the multidrug resistance of Gram-negative pathogens(1,2). However, despite efforts to develop efflux inhibitors(3), clinically useful inhibitors are not available at present(4,5). Pyridopyrimidine derivatives are AcrB- and MexB-specific inhibitors that do not inhibit MexY(6,7); MexB and MexY are principal multidrug exporters in Pseudomonas aeruginosa(8-10). We have previously determined the crystal structure of AcrB in the absence and presence of antibiotics(11-13). Drugs were shown to be exported by a functionally rotating mechanism(12) through tandem proximal and distal multisite drug-binding pockets(13). Here we describe the first inhibitor-bound structures of AcrB and MexB, in which these proteins are bound by a pyridopyrimidine derivative. The pyridopyrimidine derivative binds tightly to a narrow pit composed of a phenylalanine cluster located in the distal pocket and sterically hinders the functional rotation. This pit is a hydrophobic trap that branches off from the substrate-translocation channel. Phe 178 is located at the edge of this trap in AcrB and MexB and contributes to the tight binding of the inhibitor molecule through a pi-pi interaction with the pyridopyrimidine ring. The voluminous side chain of Trp 177 located at the corresponding position in MexY prevents inhibitor binding. The structure of the hydrophobic trap described in this study will contribute to the development of universal inhibitors of MexB and MexY in P. aeruginosa.