Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China.
Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.
Structure. 2024 Aug 8;32(8):1208-1221.e4. doi: 10.1016/j.str.2024.05.012. Epub 2024 Jun 12.
TRIP4 is a conserved transcriptional coactivator that is involved in the regulation of the expression of multiple genes. It consists of a classical N-terminal C2HC5-like zinc-finger domain and a conserved C-terminal ASCH domain. Here, we characterized the DNA-binding properties of the human TRIP4 ASCH domain. Our biochemical data show that TRIP4-ASCH has comparable binding affinities toward ssDNA and dsDNA of different lengths, sequences, and structures. The crystal structures reveal that TRIP4-ASCH binds to DNA substrates in a sequence-independent manner through two adjacent positively charged surface patches: one binds to the 5'-end of DNA, and the other binds to the 3'-end of DNA. Further mutagenesis experiments and binding assays confirm the functional roles of key residues involved in DNA binding. In summary, our data demonstrate that TRIP4-ASCH binds to the 5' and 3'-ends of DNA in a sequence-independent manner, which will facilitate further studies of the biological function of TRIP4.
TRIP4 是一种保守的转录共激活因子，参与多个基因的表达调控。它由经典的 N 端 C2HC5 样锌指结构域和保守的 C 端 ASCH 结构域组成。在这里，我们对人源 TRIP4 ASCH 结构域的 DNA 结合特性进行了表征。我们的生化数据表明，TRIP4-ASCH 与不同长度、序列和结构的 ssDNA 和 dsDNA 具有相当的结合亲和力。晶体结构揭示了 TRIP4-ASCH 通过两个相邻的正电荷表面斑块以序列非依赖性的方式结合 DNA 底物：一个结合到 DNA 的 5'端，另一个结合到 DNA 的 3'端。进一步的突变实验和结合实验证实了参与 DNA 结合的关键残基的功能作用。总之，我们的数据表明 TRIP4-ASCH 以序列非依赖性的方式结合 DNA 的 5'和 3'端，这将有助于进一步研究 TRIP4 的生物学功能。
