Mapping the Interactions between Escherichia coli TolQ Transmembrane Segments*
Mapping the Interactions between Escherichia coli TolQ Transmembrane Segments*
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绘制大肠杆菌 TolQ 跨膜片段之间的相互作用*
DOI：
10.1074/jbc.m110.192773
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
R. Lloubes
中科院分区：
文献类型：
--
作者：
X. Zhang;E. Goemaere;N. Seddiki;H. Celia;M. Gavioli;É. Cascales;R. Lloubes
tolQRAB-pal操纵子在革兰氏阴性菌基因组中是保守的。大肠杆菌的TolQRA蛋白形成内膜复合物，其中TolQR使用质子动力来调节托拉构象以及托拉C-末端区域与外膜脂蛋白的体内相互作用。TolQ、TolR和托拉的化学计量已被估计，并表明4-6个TolQ分子在复合物中缔合，因此涉及TolQ、TolR和托拉的跨膜螺旋（TMH）之间的相互作用。已提出在两个TolQ和一个TolR TMH之间的界面处形成离子通道，其涉及TolR-Asp 23、TolQ-Thr 145和TolQ-Thr 178残基。为了定义TolQ的三个TMH的组织，我们构建了TolQ的表位标记版本。体内和体外化学交联的TolQ蛋白的免疫检测表明，TolQ作为多聚体存在于复合物中。为了了解TolQ如何多聚化，我们启动了半胱氨酸扫描研究。单和串联半胱氨酸取代的结果表明，螺旋相互作用的动态模型，其中的发夹形成的最后两个TMH的TolQ改变构象，而第一TMH的TolQ形成分子内相互作用。
The tolQRAB-pal operon is conserved in Gram-negative genomes. The TolQRA proteins of Escherichia coli form an inner membrane complex in which TolQR uses the proton-motive force to regulate TolA conformation and the in vivo interaction of TolA C-terminal region with the outer membrane Pal lipoprotein. The stoichiometry of the TolQ, TolR, and TolA has been estimated and suggests that 4–6 TolQ molecules are associated in the complex, thus involving interactions between the transmembrane helices (TMHs) of TolQ, TolR, and TolA. It has been proposed that an ion channel forms at the interface between two TolQ and one TolR TMHs involving the TolR-Asp23, TolQ-Thr145, and TolQ-Thr178 residues. To define the organization of the three TMHs of TolQ, we constructed epitope-tagged versions of TolQ. Immunodetection of in vivo and in vitro chemically cross-linked TolQ proteins showed that TolQ exists as multimers in the complex. To understand how TolQ multimerizes, we initiated a cysteine-scanning study. Results of single and tandem cysteine substitution suggest a dynamic model of helix interactions in which the hairpin formed by the two last TMHs of TolQ change conformation, whereas the first TMH of TolQ forms intramolecular interactions.
影响因子：
2.9
作者：
Braun, TF;Al-Mawsawi, LQ;Blair, DF
通讯作者：
Blair, DF
基于与鞭毛马达 MotAB 的同源性，对细菌外膜受体激发剂 ExbBD/TonB 进行分子建模。
DOI：
10.1016/s0005-2736(03)00176-7
发表时间：
2003
期刊：
Biochimica et biophysica acta
影响因子：
--
作者：
Zhai,YuFeng;Heijne,Wilbert;SaierJr,MiltonH
通讯作者：
SaierJr,MiltonH
影响因子：
2.9
作者：
Braun, TF;Blair, DF
通讯作者：
Blair, DF