Zhu Rongfeng, Hao Ziyang, Lou Hubing, Song Yanqun, Zhao Jingyi, Chen Yuqing, Zhu Jiuhe, Chen Peng R
Academy for Advanced Interdisciplinary Studies, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
Beijing National Laboratory for Molecular Sciences, Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
J Biol Inorg Chem. 2017 Jul;22(5):685-693. doi: 10.1007/s00775-017-1442-7. Epub 2017 Jan 25.
Multiple antibiotic resistance regulator (MarR) family proteins are widely conserved transcription factors that control bacterial resistance to antibiotics, environmental stresses, as well as the regulation of virulence determinants. Escherichia coli MarR, the prototype member of this family, has recently been shown to undergo copper(II)-catalyzed inter-dimer disulfide bond formation via a unique cysteine residue (Cys80) residing in its DNA-binding domain. However, despite extensive structural characterization of the MarR family proteins, the structural mechanism for DNA binding of this copper(II)-sensing MarR factor remains elusive. Here, we report the crystal structures of DNA-bound forms of MarR, which revealed a unique, concerted generation of two new helix-loop-helix motifs that facilitated MarR's DNA binding. Structural analysis and electrophoretic mobility shift assays (EMSA) show that the flexibility of Gly116 in the center of helix α5 and the extensive hydrogen-bonding interactions at the N-terminus of helix α1 together assist the reorientation of the wHTH domains and stabilize MarR's DNA-bound conformation.
多重抗生素抗性调节因子（MarR）家族蛋白是广泛保守的转录因子，可控制细菌对抗生素的抗性、环境压力以及毒力决定因素的调节。大肠杆菌MarR是该家族的原型成员，最近已证明它通过位于其DNA结合结构域中的独特半胱氨酸残基（Cys80）经历铜（II）催化的二聚体间二硫键形成。然而，尽管对MarR家族蛋白进行了广泛的结构表征，但这种铜（II）感应MarR因子与DNA结合的结构机制仍然难以捉摸。在这里，我们报告了与DNA结合的MarR形式的晶体结构，该结构揭示了两个新的螺旋-环-螺旋基序的独特协同生成，这促进了MarR与DNA的结合。结构分析和电泳迁移率变动分析（EMSA）表明，α5螺旋中心的Gly116的灵活性以及α1螺旋N端广泛的氢键相互作用共同协助wHTH结构域重新定向并稳定MarR与DNA结合的构象。
