Temboot Pornvichai, Lee Ronald F S, Menin Laure, Patiny Luc, Dyson Paul J, Ratanaphan Adisorn
Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand.
Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne CH-1015, Switzerland.
Biochem Biophys Res Commun. 2017 Jun 24;488(2):355-361. doi: 10.1016/j.bbrc.2017.05.052. Epub 2017 May 10.
RAPTA compounds, ([Ru(η-arene)(PTA)Cl], PTA = 1,3,5-triaza-7-phosphaadamantane), have been reported to overcome drug resistance in cisplatin resistant cells. However, the exact mechanism of these complexes is still largely unexplored. In this study, the interaction of some RAPTA compounds with the N-terminal fragment of the BRCA1 RING domain protein was investigated. The binding of the RAPTA compounds to the BRCA1 protein resulted in a release of Zn ions in a dose and time dependent manner, as well as thermal alteration of ruthenated-BRCA1 proteins. Electron Transfer Dissociation (ETD) fragmentation mass spectrometry revealed the preferential binding sites of the RAPTA complexes on the BRCA1 zinc finger RING domain at a similar short peptide stretch, CysLysPheCysMetLeu and Lys (residues 44-49 and 55 on full length BRCA1). Changes in the conformation and binding constants of ruthenium-BRCA1 adducts were established, resulting in inactivation of the RING heterodimer BRCA1/BARD1-mediated E3 ubiquitin ligase function. These findings could provide mechanistic insight into the mode of action of RAPTA complexes for on tested BRCA1 model protein.
RAPTA化合物（[Ru(η-芳烃)(PTA)Cl]，PTA = 1,3,5-三氮杂-7-磷杂金刚烷）已被报道可克服顺铂耐药细胞中的耐药性。然而，这些配合物的确切作用机制仍在很大程度上未被探索。在本研究中，研究了一些RAPTA化合物与BRCA1 RING结构域蛋白N端片段的相互作用。RAPTA化合物与BRCA1蛋白的结合导致锌离子以剂量和时间依赖性方式释放，以及钌化BRCA1蛋白的热变化。电子转移解离（ETD）碎裂质谱揭示了RAPTA配合物在BRCA1锌指RING结构域上相似的短肽段CysLysPheCysMetLeu和Lys（全长BRCA1上的第44 - 49位和第55位残基）上的优先结合位点。确定了钌 - BRCA1加合物的构象和结合常数的变化，导致RING异二聚体BRCA1/BARD1介导的E3泛素连接酶功能失活。这些发现可为RAPTA配合物对所测试的BRCA1模型蛋白的作用方式提供机制性见解。
