Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland.
PSL Research University, CNRS-UMR 9187, INSERM U1196, Institut Curie, 91405, Orsay, France.
Chemistry. 2021 Jan 13;27(3):1113-1121. doi: 10.1002/chem.202004040. Epub 2020 Dec 8.
Stabilizing the DNA and RNA structures known as G-quadruplexes (G4s) using specific ligands is a strategy that has been proposed to fight cancer. However, although G-quadruplex:ligand (G4:L) interactions have often been investigated, whether or not ligands are able to disrupt G-quadruplex:protein (G4:P) interactions remains poorly studied. In this study, using native mass spectrometry, we have investigated ternary G4:L:P complexes formed by G4s, some of the highest affinity ligands, and the binding domain of the RHAU helicase. Our results suggest that RHAU binds not only preferentially to parallel G4s, but also to free external G-quartets. We also found that, depending on the G4, ligands could prevent the binding of the peptide, either by direct competition for the binding sites (orthosteric inhibition) or by inducing conformational changes (allosteric inhibition). Notably, the ligand Cu-ttpy (ttpy=4'-tolyl-2,2':6',2''-terpyridine) induced a conformational change that increased the binding of the peptide. This study illustrates that it is important to not only characterize drug-target interactions, but also how the binding to other partners is affected.
使用特定配体稳定被称为 G-四链体 (G4s) 的 DNA 和 RNA 结构是一种被提议用于对抗癌症的策略。然而，尽管 G-四链体:配体 (G4:L) 相互作用经常被研究，但配体是否能够破坏 G-四链体:蛋白质 (G4:P) 相互作用仍然研究甚少。在这项研究中，我们使用天然质谱法研究了 G4s、一些最高亲和力的配体和 RHAU 解旋酶结合域形成的三元 G4:L:P 复合物。我们的结果表明，RHAU 不仅优先结合平行 G4s，还结合游离的外部 G-四联体。我们还发现，根据 G4 的不同，配体可以通过直接竞争结合位点（正变构抑制）或诱导构象变化（变构抑制）来阻止肽的结合。值得注意的是，配体 Cu-ttpy（ttpy=4'-甲苯基-2,2':6',2''-三联吡啶）诱导了构象变化，增加了肽的结合。这项研究表明，不仅要表征药物-靶标相互作用，还要研究与其他伙伴的结合如何受到影响，这一点很重要。
