Three-dimensional structure of a bacterial oxalate transporter
Three-dimensional structure of a bacterial oxalate transporter
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DOI：
10.1038/nsb821
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发表时间：
2002-08-01
期刊：
影响因子：
--
通讯作者：
Subramaniam, S
中科院分区：
文献类型：
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作者：
Hirai, T;Heymann, JAW;Subramaniam, S
主要易化因子超家族（MFS）代表了进化上相关的膜转运蛋白的最大类别之一。在这里，我们提出了在6.5埃分辨率的细菌成员，这个超家族，OAT的三维结构。该结构来自二维晶体的电子晶体学分析，揭示了OAT分子中的12个螺旋围绕中心空腔排列，该空腔在膜中心最宽。螺旋自然地分为三组：包括螺旋3、6、9和12的外围组;包括螺旋2、5、8和11的第二组，其面对穿过膜的大部分长度的中心底物运输途径;和第三组，其包含在胞质侧（4和10）或周质侧（1和7）参与该途径的螺旋1、4、7和10。总的来说，蛋白质的结构是非常对称的，为这种转运蛋白进行双向底物转运的能力提供了令人信服的分子解释。
The major facilitator superfamily (MFS) represents one of the largest classes of evolutionarily related membrane transporter proteins. Here we present the three-dimensional structure at 6.5 Angstrom resolution of a bacterial member of this superfamily, OAT. The structure, derived from an electron crystallographic analysis of two-dimensional crystals, reveals that the 12 helices in the OAT molecule are arranged around a central cavity, which is widest at the center of the membrane. The helices divide naturally into three groups: a peripheral set comprising helices 3, 6, 9 and 12; a second set comprising helices 2, 5, 8 and 11 that faces the central substrate transport pathway across most of the length of the membrane; and a third set comprising helices 1, 4, 7 and 10 that participate in the pathway either on the cytoplasmic side (4 and 10) or on the periplasmic side (1 and 7). Overall, the architecture of the protein is remarkably symmetric, providing a compelling molecular explanation for the ability of such transporters to carry out bi-directional substrate transport.