Search

Silver nanoparticles (AgNPs) modified by luminescent Ru(ii) complexes not only possess bright red fluorescence but also can target lysosomes. Cell imaging and a cytotoxicity study suggest that Ru1–2·AgNPs may act as a potential theranostic agent. [ABSTRACT FROM AUTHOR]

In this paper, three new Ruthenium(II) polypyridyl complexes containing ascididemin (ASC) as main ligand have been synthesized and characterized. Their interactions with different G-quadruplex (Htelo, c-myc and c-kit) (Htelo: human telomeric DNA, c-myc: cellular-myelocytomatosis viral oncogene, c-kit: oncogene c-kit promoter sequences) and duplex (ds26) DNA sequences were comparatively studied with the free ligand ASC by a series of spectroscopic techniques including UV–vis (ultraviolet-visible) spectroscopy, FID (fluorescent intercalator displacement) assay, and FRET (fluorescence resonance energy transfer) melting assay. Molecular docking studies were also performed to support the binding mode of the compounds with G-quadruplex DNA. Results indicated that [Ru(bpy) 2 ASC]·(PF 6) 2 (1), [Ru(phen) 2 ASC]·(PF 6) 2 (2), [Ru(tatp) 2 ASC]·(PF 6) 2 (3) (bpy = 2,2′‑bipyridine, phen = 1,10‑phenanthroline, tatp = 1,4,8,9‑tetra‑aza‑triphenylene) and ASC can effectively bind G-quadruplex and duplex DNA and stabilization ability lies in the order 3 > 2 > 1 > ASC. Complex 3 was determined to be the most promising candidate for further in vitro studies and potential anticancer drug. The act of conjugating ascididemin (ASC) ligands to a Ru(II) polypyridyl subunits resulted in a class of excellent DNA binders. Especially, [Ru(1,4,8,9‑tetra‑aza‑triphenylene) 2 ASC]·(PF 6) 2 (3) showed the strongest quadruplex and duplex DNA binding and stabilization ability. Complex 3 was proposed to be the promising telomerase inhibitors and potential anticancer drug. Unlabelled Image • Three novel Ru(II) polypyridyl complexes have been synthesized and characterized. • Complexes 1 – 3 and ascididemin (ASC) can effectively bind G-quadruplex and duplex DNA. • Notably, complex 3 exhibited the strongest DNA binding and stabilization ability. • Complex 3 was determined to be the most promising candidate for further in vitro studies. • Complex 3 is [Ru(1,4,8,9‑tetra‑aza‑triphenylene) 2 ASC]·(PF 6) 2. [ABSTRACT FROM AUTHOR]

Chiral recognition of DNA molecules is important because much evidence has indicated that transformations of chirality and diverse conformations of DNA are involved in a series of key biological events. Among these, enrichment of G-quadruplexes (GQs) in the genome, and the exploration of their multiple structures, has aroused great interest. Herein, we compared nearly 100 different sequences with 3′-tail sequences of variable length or different linkers or diverse loops and mutative ionic concentrations. All sequences were capable of forming stable GQs, with fluorescence signal enhancement upon binding with Δ- and Λ- [Ru(bpy)2(dppz-idzo)]2+ (Δ/Λ-1). Our results show that multiple factors, including the 3′-tail length, linkers, loop length and ionic concentration, regulate the enantioselectivity of GQs. Furthermore, molecular docking simulations revealed that chiral recognition of GQs depends on the binding site. To the best of our knowledge, this is the first systematic study regarding the regulation of multi-factors for GQ selectivity of chiral Ru-complexes. These results will serve as a useful reference for enantioselective recognition of genomic GQs and may facilitate the development of chiral anticancer agents for targeting GQs. [ABSTRACT FROM AUTHOR]