Kazan (Volga region) Federal University, Department of Microbiology, Kremlevskaya 18, 420008 Kazan, Russia.
FEBS Lett. 2013 May 2;587(9):1293-8. doi: 10.1016/j.febslet.2013.03.015. Epub 2013 Mar 25.
The Bacillus subtilis glutamine synthetase (GS) plays a dual role in cell metabolism by functioning as catalyst and regulator. GS catalyses the ATP-dependent synthesis of glutamine from glutamate and ammonium. Under nitrogen-rich conditions, GS becomes feedback-inhibited by high intracellular glutamine levels and then binds transcription factors GlnR and TnrA, which control the genes of nitrogen assimilation. While GS-bound TnrA is no longer able to interact with DNA, GlnR-DNA binding is shown to be stimulated by GS complex formation. In this paper we show a new physiological feature of the interaction between glutamine synthetase and TnrA. The transcription factor TnrA inhibits the biosynthetic activity of glutamine synthetase in vivo and in vitro, while the GlnR protein does not affect the activity of the enzyme.
枯草芽孢杆菌谷氨酰胺合成酶 (GS) 通过作为催化剂和调节剂在细胞代谢中发挥双重作用。GS 催化 ATP 依赖性将谷氨酸和铵转化为谷氨酰胺。在氮源丰富的条件下，GS 会被细胞内高浓度的谷氨酰胺反馈抑制，然后与氮同化基因的转录因子 GlnR 和 TnrA 结合。当 GS 结合的 TnrA 不再能够与 DNA 相互作用时，GlnR-DNA 结合被证明受到 GS 复合物形成的刺激。在本文中，我们展示了谷氨酰胺合成酶和 TnrA 之间相互作用的一个新的生理特征。转录因子 TnrA 抑制体内和体外谷氨酰胺合成酶的生物合成活性，而 GlnR 蛋白不影响酶的活性。
