Backbone Structure of Transmembrane Domain IX of the Na+/Proline Transporter PutP of Escherichia coli
Backbone Structure of Transmembrane Domain IX of the Na+/Proline Transporter PutP of Escherichia coli
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DOI：
10.1016/j.bpj.2008.09.030
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发表时间：
2009-01-07
影响因子：
3.4
通讯作者：
Jeschke, Gunnar
中科院分区：
文献类型：
--
作者：
Hilger, Daniel;Polyhach, Yevhen;Jeschke, Gunnar
的骨干结构是由定点自旋标记，双电子电子共振测量的距离，和建模方面的螺旋环螺旋结构的跨膜结构域，这是应该行的易位途径中的54.3 kDa的Na+/脯氨酸同向转运蛋白PutP的大肠杆菌。自旋标记的构象分布由旋转异构体库来解释。骨干模型的根均方差小于2埃的合奏。这些模型在残基T341附近表现出明显的扭结，其参与底物结合。扭结可以与允许蛋白质打开和关闭向内定向的腔的铰链相关联。
The backbone structure is determined by site-directed spin labeling, double electron electron resonance measurements of distances, and modeling in terms of a helix-loop-helix construct for a transmembrane domain that is supposed to line the translocation pathway in the 54.3 kDa Na+/proline symporter PutP of Escherichia coli. The conformational distribution of the spin labels is accounted for by a rotamer library. An ensemble of backbone models with a root mean-square deviation of less than 2 angstrom is obtained. These models exhibit a pronounced kink near residue T341, which is involved in substrate binding. The kink may be associated with a hinge that allows the protein to open and close an inwardly oriented cavity.