Characterizing activation mechanisms and binding preferences of ruthenium metallo-prodrugs by a competitive binding assay
- Author(s)
- Christian Artner, Hannah U. Holtkamp, Christian G. Hartinger, Samuel M. Meier-Menches
- Abstract
The activation mechanisms and reactivity of ruthenium metallo-prodrug lead structures were investigated in detail using capillary zone electrophoresis mass spectrometry (CZE–MS) in a time-dependent manner and by exposing to a protein/oligonucleotide mixture. The competitive assays were performed with sodium trans-[RuCl 4(HInd) 2] where Hind = indazole (NKP-1339), [(η 6-p-cymene)RuCl 2(pta)], where pta = 1,3,5-triaza-7-phosphaadamantane (RAPTA-C) and [(η 6-biphenyl)RuCl(1,2-ethylenediamine)]PF 6 (RM175). Molecular and quantitative information on binding preferences was obtained by coupling CZE to electrospray ionization MS (ESI-MS) and inductively coupled plasma MS (ICP-MS), respectively. A score system is presented that ranks the binding preferences of Ru complexes with nucleotides and demonstrated the following trend of decreasing selectivity after 24 h: RM175 (0.89) > RAPTA-C (0.78) > NKP-1339 (0.40). As expected, the organometallic drug candidates RM175 and RAPTA-C underwent a halido/aqua ligand exchange reaction at the metal center and showed distinct reactivity towards the biomolecules. In particular, the protein/DNA binding sites of RAPTA-C in a mixture of protein (ubiquitin) and oligonucleotide (5′-dATTGGCAC-3′) were located at single-amino acid and single-nucleotide resolution, respectively. Activated RAPTA-C bound selectively to Met1, adenine and cytosine in this setting, which contrasts with the selectivity of RM175 for guanine. Finally, activation products of NKP-1339 were detected corresponding to Ru II(Hind) 2 fragments coordinated to the oligonucleotide, which represents one of the few examples of a directly observed Ru II adduct.
- Organisation(s)
- Department of Inorganic Chemistry, Department of Analytical Chemistry
- External organisation(s)
- University of Auckland
- Journal
- Journal of Inorganic Biochemistry
- Volume
- 177
- Pages
- 322-327
- No. of pages
- 6
- ISSN
- 0162-0134
- DOI
- https://doi.org/10.1016/j.jinorgbio.2017.07.010
- Publication date
- 12-2017
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 104003 Inorganic chemistry, 106002 Biochemistry, 106023 Molecular biology
- Keywords
- ASJC Scopus subject areas
- Biochemistry, Inorganic Chemistry
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/c30bd195-1acd-4f6d-81af-af3e81c1c5ed