Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel, 5290002.
Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260.
Chembiochem. 2024 Aug 1;25(15):e202400279. doi: 10.1002/cbic.202400279. Epub 2024 Jul 5.
Bacteria use specialized proteins, like transcription factors, to rapidly control metal ion balance. CueR is a Gram-negative bacterial copper regulator. The structure of E. coli CueR complexed with Cu(I) and DNA was published, since then many studies have shed light on its function. However, P. aeruginosa CueR, which shows high sequence similarity to E. coli CueR, has been less studied. Here, we applied room-temperature electron paramagnetic resonance (EPR) measurements to explore changes in dynamics of P. aeruginosa CueR in dependency of copper concentrations and interaction with two different DNA promoter regions. We showed that P. aeruginosa CueR is less dynamic than the E. coli CueR protein and exhibits much higher sensitivity to DNA binding as compared to its E. coli CueR homolog. Moreover, a difference in dynamical behavior was observed when P. aeruginosa CueR binds to the copZ2 DNA promoter sequence compared to the mexPQ-opmE promoter sequence. Such dynamical differences may affect the expression levels of CopZ2 and MexPQ-OpmE proteins in P. aeruginosa. Overall, such comparative measurements of protein-DNA complexes derived from different bacterial systems reveal insights about how structural and dynamical differences between two highly homologous proteins lead to quite different DNA sequence-recognition and mechanistic properties.
细菌使用专门的蛋白质，如转录因子，来快速控制金属离子平衡。CueR 是一种革兰氏阴性细菌铜调节蛋白。大肠杆菌 CueR 与 Cu(I)和 DNA 形成复合物的结构已经发表，此后许多研究揭示了其功能。然而，与大肠杆菌 CueR 具有高度序列相似性的铜绿假单胞菌 CueR 研究较少。在这里，我们应用室温电子顺磁共振（EPR）测量来研究铜浓度依赖性和与两种不同 DNA 启动子区域相互作用时铜绿假单胞菌 CueR 动力学的变化。我们表明，铜绿假单胞菌 CueR 的动态性低于大肠杆菌 CueR 蛋白，并且与大肠杆菌 CueR 同系物相比，对 DNA 结合的敏感性更高。此外，当铜绿假单胞菌 CueR 结合到 copZ2 DNA 启动子序列而不是 mexPQ-opmE 启动子序列时，观察到动态行为的差异。这种动态差异可能会影响铜绿假单胞菌中 CopZ2 和 MexPQ-OpmE 蛋白的表达水平。总体而言，来自不同细菌系统的蛋白质-DNA 复合物的这种比较测量揭示了结构和动力学差异如何导致两种高度同源蛋白质具有截然不同的 DNA 序列识别和机制特性。
