Differentiation of DctA and DcuS function in the DctA/DcuS sensor complex of Escherichia coli: function of DctA as an activity switch and of DcuS as the C4‐dicarboxylate sensor
Differentiation of DctA and DcuS function in the DctA/DcuS sensor complex of Escherichia coli: function of DctA as an activity switch and of DcuS as the C4‐dicarboxylate sensor
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大肠杆菌 DctA/DcuS 传感器复合物中 DctA 和 DcuS 功能的区分：DctA 作为活性开关的功能和 DcuS 作为 C4-二羧酸盐传感器的功能
DOI：
10.1111/mmi.12759
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发表时间：
2014
影响因子：
3.6
通讯作者：
G. Unden
中科院分区：
文献类型：
--
作者：
P. Steinmetz;Sebastian Wörner;G. Unden
传感器激酶dcu的C4 -二羧酸反应性仅与C4 -二羧酸转运体DctA或DcuB一致。分析了DctA和dcu在DctA/ dcu传感器复合物功能中的各自作用。(i) DctA的C4 -二羧酸位点的DctA（S380D）变体赋予DctA/DcuS复合物中C4 -二羧酸对dcu的敏感性，但缺乏在C4 -二羧酸上的运输和生长。因此，DctA的转运活性不需要它在传感器复合体中的功能。（ii）富马酸等效应物诱导DctA/ dcu依赖性报告基因（dcuB-lacZ）的表达，并作为DctA的底物，而柠檬酸盐仅作为dcuB-lacZ的诱导剂，不影响DctA的功能。（iii）富马酸诱导dcu - lacz所需的浓度比通过DctA （Km = 30 μM）转运所需的浓度高33倍，表明在这两个过程中存在不同的富马酸位点。（iv）在增加dctA表达水平的滴定实验中，dctA对dcu C4 -二羧酸盐敏感性的影响呈浓度依赖性。数据一致表明，DctA/ dcu对C4‐二羧酸盐的感知存在于dcu中，DctA作为活性开关。将dcu从本构态ON转移到C4 -二羧酸反应状态，需要DctA的存在，但不需要DctA的转运。
The C4‐dicarboxylate responsiveness of the sensor kinase DcuS is only provided in concert with C4‐dicarboxylate transporters DctA or DcuB. The individual roles of DctA and DcuS for the function of the DctA/DcuS sensor complex were analysed. (i) Variant DctA(S380D) in the C4‐dicarboxylate site of DctA conferred C4‐dicarboxylate sensitivity to DcuS in the DctA/DcuS complex, but was deficient for transport and for growth on C4‐dicarboxylates. Consequently transport activity of DctA is not required for its function in the sensor complex. (ii) Effectors like fumarate induced expression of DctA/DcuS‐dependent reporter genes (dcuB–lacZ) and served as substrates of DctA, whereas citrate served only as an inducer of dcuB–lacZ without affecting DctA function. (iii) Induction of dcuB–lacZ by fumarate required 33‐fold higher concentrations than for transport by DctA (Km = 30 μM), demonstrating the existence of different fumarate sites for both processes. (iv) In titration experiments with increasing dctA expression levels, the effect of DctA on the C4‐dicarboxylate sensitivity of DcuS was concentration dependent. The data uniformly show that C4‐dicarboxylate sensing by DctA/DcuS resides in DcuS, and that DctA serves as an activity switch. Shifting of DcuS from the constitutive ON to the C4‐dicarboxylate responsive state, required presence of DctA but not transport by DctA.
DOI：
10.1046/j.1432-1033.2003.03507.x
发表时间：
2003-04
期刊：
European journal of biochemistry
影响因子：
--
作者：
Christian Schwoppe;Herbert H. Winkler;H. Neuhaus
通讯作者：
Christian Schwoppe;Herbert H. Winkler;H. Neuhaus
影响因子：
3.2
作者：
Kallenberg, Felix;Dintner, Sebastian;Gebhard, Susanne
通讯作者：
Gebhard, Susanne