Structural insights into redox signal transduction mechanisms in the control of nitrogen fixation by the NifLA system.
Structural insights into redox signal transduction mechanisms in the control of nitrogen fixation by the NifLA system.
复制标题
对NifLA系统控制固氮的氧化还原信号转导机制的结构见解。
DOI：
10.1073/pnas.2302732120
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发表时间：
2023-07-25
影响因子：
11.1
通讯作者：
Peters, John W.
中科院分区：
文献类型：
--
作者：
Boyer, Nathaniel R.;Tokmina-Lukaszewska, Monika;Batista, Marcelo Bueno;Mus, Florence;Dixon, Ray;Bothner, Brian;Peters, John W.
关键词：
双组分系统对于调节细菌基因表达以响应环境信号至关重要。在变形杆菌中，NIFL-NIFA系统调节与生物固氮相关的基因的表达，以响应细胞内的氧气、细胞能量和碳氮比。NIFL的修饰已被证明能促进模型重氮菌中氨的排泄。解析NIFL在活性构象和非活性构象中的结构为深入了解非规范的双组分调控系统中的信号转导提供了关键的见解，并为合成生物学方法用于工程生物肥料奠定了基础，该工程生物肥料与多种作物相容。Nif1是一种构象动态的黄素蛋白，负责调节依赖于σ54的激活因子NifA的活性，从而控制固氮(NIF)基因的转录，以响应细胞内的氧气、细胞能量或氮素的可获得性。NIFL-NIFA双组分系统是固氮的主调节系统。NIFL作为一种感觉蛋白，经历信号依赖的构象变化，调节其与NIFA的相互作用，形成NIFL-NIFA复合体，在不适合固氮的条件下抑制NIFA的活性。虽然NIFL-NIFA的调控是众所周知的，但这些构象灵活的蛋白质之前在结构确定方面的尝试都是失败的。在这里描述的工作中，我们提出了一个NIFL二聚体的结构模型，该模型由散射技术和质谱(MS)耦合结构分析相结合来支持，该结构分析报告了溶液中的平均结构。结合小角X射线散射得到的电子密度图和MS耦合表面标记，我们研究了NIFL氧和能量响应的构象动力学。我们的结果揭示了还原和氧化条件下NIFL结构的构象差异，这为在模式重氮菌棕色固氮菌中调节NIFLA复合体的形成提供了基础。
Two-component systems are critically important to modulating bacterial gene expression in response to environmental signals. In Proteobacteria, the NifL-NifA system regulates the expression of genes related to biological nitrogen fixation in response to intracellular oxygen, cellular energy, and the carbon–nitrogen ratio. Modifications of nifL have been demonstrated to promote the excretion of ammonium in model diazotrophs. Resolving the structure of NifL in active and inactive conformations provides key insights into signal transduction in the noncanonical two-component regulatory system and lays the groundwork for synthetic biology approaches for engineering biofertilizers that are compatible with a wide variety of crop plants. NifL is a conformationally dynamic flavoprotein responsible for regulating the activity of the σ54-dependent activator NifA to control the transcription of nitrogen fixation (nif) genes in response to intracellular oxygen, cellular energy, or nitrogen availability. The NifL-NifA two-component system is the master regulatory system for nitrogen fixation. NifL serves as a sensory protein, undergoing signal-dependent conformational changes that modulate its interaction with NifA, forming the NifL–NifA complex, which inhibits NifA activity in conditions unsuitable for nitrogen fixation. While NifL-NifA regulation is well understood, these conformationally flexible proteins have eluded previous attempts at structure determination. In work described here, we advance a structural model of the NifL dimer supported by a combination of scattering techniques and mass spectrometry (MS)-coupled structural analyses that report on the average structure in solution. Using a combination of small angle X-ray scattering-derived electron density maps and MS-coupled surface labeling, we investigate the conformational dynamics responsible for NifL oxygen and energy responses. Our results reveal conformational differences in the structure of NifL under reduced and oxidized conditions that provide the basis for a model for modulating NifLA complex formation in the regulation of nitrogen fixation in response to oxygen in the model diazotroph, Azotobacter vinelandii.
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影响因子：
4.8
作者：
Arcondéguy, T;Lawson, D;Merrick, M
通讯作者：
Merrick, M
DOI：
10.1073/pnas.1813586116
发表时间：
2019-03-12
影响因子：
11.1
作者：
Dikiy, Igor;Edupuganti, Uthama R.;Gardner, Kevin H.
通讯作者：
Gardner, Kevin H.
影响因子：
3.2
作者：
EYDMANN, T;SODERBACK, E;DIXON, R
通讯作者：
DIXON, R
影响因子：
6.1
作者：
Franke D;Petoukhov MV;Konarev PV;Panjkovich A;Tuukkanen A;Mertens HDT;Kikhney AG;Hajizadeh NR;Franklin JM;Jeffries CM;Svergun DI
通讯作者：
Svergun DI
影响因子：
2.9
作者：
Ayers, Rebecca A.;Moffat, Keith
通讯作者：
Moffat, Keith