Three-dimensional structure of the bacterial multidrug transporter EmrE shows it is an asymmetric homodimer
Three-dimensional structure of the bacterial multidrug transporter EmrE shows it is an asymmetric homodimer
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DOI：
10.1093/emboj/cdg611
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发表时间：
2003-12-01
期刊：
影响因子：
11.4
通讯作者：
Tate, CG
中科院分区：
文献类型：
--
作者：
Ubarretxena-Belandia, I;Baldwin, JM;Tate, CG
小的多药耐药转运蛋白家族广泛存在于细菌中，并且通过质子连接的外排负责细菌对有毒芳香族阳离子的耐药性。我们已经确定了三维（3D）结构的大肠杆菌多药转运蛋白EmrE的电子低温显微镜的2D晶体，包括数据到7.0埃的分辨率。EmrE的结构由一束八个跨膜α-螺旋组成，其中一个底物分子在中心附近结合。底物结合室由六个螺旋形成，并且可从水相和从脂质双层侧向进入。EmrE结构的最显著特征是它是不对称的同源二聚体。基于三维密度图讨论了EmrE二聚体中两种多肽的可能排列。
The small multidrug resistance family of transporters is widespread in bacteria and is responsible for bacterial resistance to toxic aromatic cations by proton-linked efflux. We have determined the three-dimensional (3D) structure of the Escherichia coli multidrug transporter EmrE by electron cryomicroscopy of 2D crystals, including data to 7.0 Angstrom resolution. The structure of EmrE consists of a bundle of eight transmembrane alpha-helices with one substrate molecule bound near the centre. The substrate binding chamber is formed from six helices and is accessible both from the aqueous phase and laterally from the lipid bilayer. The most remarkable feature of the structure of EmrE is that it is an asymmetric homodimer. The possible arrangement of the two polypeptides in the EmrE dimer is discussed based on the 3D density map.