Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia.
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia.
Int J Mol Sci. 2023 Sep 16;24(18):14187. doi: 10.3390/ijms241814187.
The natural flavonoid epigallocatechin gallate has a wide range of biological activities, including being capable of binding to nucleic acids; however, the mechanisms of the interactions of epigallocatechin gallate with DNA organized in chromatin have not been systematically studied. In this work, the interactions of epigallocatechin gallate with chromatin in cells and with nucleosomes and chromatosomes in vitro were studied using fluorescent microscopy and single-particle Förster resonance energy transfer approaches, respectively. Epigallocatechin gallate effectively penetrates into the nuclei of living cells and binds to DNA there. The interaction of epigallocatechin gallate with nucleosomes in vitro induces a large-scale, reversible uncoiling of nucleosomal DNA that occurs without the dissociation of DNA or core histones at sub- and low-micromolar concentrations of epigallocatechin gallate. Epigallocatechin gallate does not reduce the catalytic activity of poly(ADP-ribose) polymerase 1, but causes the modulation of the structure of the enzyme-nucleosome complex. Epigallocatechin gallate significantly changes the structure of chromatosomes, but does not cause the dissociation of the linker histone. The reorganization of nucleosomes and chromatosomes through the use of epigallocatechin gallate could facilitate access to protein factors involved in DNA repair, replication and transcription to DNA and, thus, might contribute to the modulation of gene expression through the use of epigallocatechin gallate, which was reported earlier.
天然类黄酮表没食子儿茶素没食子酸酯具有广泛的生物学活性，包括能够与核酸结合；然而，表没食子儿茶素没食子酸酯与染色质中组织化的 DNA 相互作用的机制尚未得到系统研究。在这项工作中，使用荧光显微镜和单粒子Förster 共振能量转移方法分别研究了表没食子儿茶素没食子酸酯在细胞内与染色质以及在体外与核小体和染色质小体的相互作用。表没食子儿茶素没食子酸酯有效地穿透活细胞的核，并在那里与 DNA 结合。表没食子儿茶素没食子酸酯与体外核小体的相互作用诱导核小体 DNA 的大规模、可逆解旋，这种解旋发生在亚毫摩尔和低毫摩尔浓度的表没食子儿茶素没食子酸酯下，不会导致 DNA 或核心组蛋白的解离。表没食子儿茶素没食子酸酯不会降低多聚（ADP-核糖）聚合酶 1 的催化活性，但会引起酶-核小体复合物结构的调制。表没食子儿茶素没食子酸酯显著改变染色质小体的结构，但不会导致连接组蛋白的解离。通过使用表没食子儿茶素没食子酸酯对核小体和染色质小体的重新组织可以促进与 DNA 修复、复制和转录相关的蛋白质因子的进入，从而可能有助于通过之前报道的表没食子儿茶素没食子酸酯调节基因表达。
