Padmanabhan Balasundaram, Tong Kit I, Ohta Tsutomu, Nakamura Yoshihiro, Scharlock Maria, Ohtsuji Makiko, Kang Moon-Il, Kobayashi Akira, Yokoyama Shigeyuki, Yamamoto Masayuki
RIKEN Genomic Sciences Center, Tsurumi, Yokohama 230-0045, Japan.
Mol Cell. 2006 Mar 3;21(5):689-700. doi: 10.1016/j.molcel.2006.01.013.
Nrf2 regulates the cellular oxidative stress response, whereas Keap1 represses Nrf2 through its molecular interaction. To elucidate the molecular mechanism of the Keap1 and Nrf2 interaction, we resolved the six-bladed beta propeller crystal structure of the Kelch/DGR and CTR domains of mouse Keap1 and revealed that extensive inter- and intrablade hydrogen bonds maintain the structural integrity and proper association of Keap1 with Nrf2. A peptide containing the ETGE motif of Nrf2 binds the beta propeller of Keap1 at the entrance of the central cavity on the bottom side via electrostatic interactions with conserved arginine residues. We found a somatic mutation and a gene variation in human lung cancer cells that change glycine to cysteine in the DGR domain, introducing local conformational changes that reduce Keap1's affinity for Nrf2. These results provide a structural basis for the loss of Keap1 function and gain of Nrf2 function.
Nrf2调节细胞氧化应激反应，而Keap1通过其分子相互作用抑制Nrf2。为阐明Keap1与Nrf2相互作用的分子机制，我们解析了小鼠Keap1的Kelch/DGR和CTR结构域的六叶β-螺旋桨晶体结构，发现广泛的叶片间和叶片内氢键维持了Keap1的结构完整性以及与Nrf2的正确结合。含有Nrf2的ETGE基序的肽通过与保守精氨酸残基的静电相互作用，在中央腔底部入口处与Keap1的β-螺旋桨结合。我们在人肺癌细胞中发现了一个体细胞突变和一个基因变异，它们在DGR结构域中将甘氨酸变为半胱氨酸，引入了局部构象变化，降低了Keap1对Nrf2的亲和力。这些结果为Keap1功能丧失和Nrf2功能获得提供了结构基础。
