Induction of a Four‐Way Junction Structure in the DNA Palindromic Hexanucleotide 5′‐d(CGTACG)‐3′ by a Mononuclear Platinum Complex

Abstract

Four‐way junctions (4WJs) are supramolecular DNA assemblies comprising four interacting DNA strands that in biology are involved in DNA‐damage repair. In this study, a new mononuclear platinum(II) complex 1 was prepared that is capable of driving the crystallization of the DNA oligomer 5′‐d(CGTACG)‐3′ specifically into a 4WJ‐like motif. In the crystal structure of the 1 –CGTACG adduct, the distorted‐square‐planar platinum complex binds to the core of the 4WJ‐like motif through π–π stacking and hydrogen bonding, without forming any platinum–nitrogen coordination bonds. Our observations suggest that the specific molecular properties of the metal complex are crucially responsible for triggering the selective assembly of this peculiar DNA superstructure.

Ruthenium-based PACT agents based on bisquinoline chelates: synthesis, photochemistry, and cytotoxicity

“…Probably, the higher lipophilicity of [2](PF 6 ) 2 and [3](PF 6 ) 2 , compared to their bpy analog, is at least partly responsible for their higher uptake. However, the more polar (log P ow = 0.45) i-Hdiqa complex [3] 2+ showed enhanced [29], or in our group by platinum(II) complexes [48]; however, the reason for such phenomenon in ruthenium(II) complexes remain unclear. Next to hypothesizing some form of active transport, we may also speculate that metal complexes bearing non-coordinated NH groups such as [3] 2+ , may partly be deprotonated because of the increased acidity of the NH group upon metal coordination, which may lower the charge of the metal complex and hence improve cellular uptake by passive diffusion.…”

Intracellular Dynamic Assembly of Deep‐Red Emitting Supramolecular Nanostructures Based on the Pt…Pt Metallophilic Interaction

“…After 24 h treatment with 5 µ m of [1]OAc and [2]OAc, a very high platinum cellular uptake was observed, as measured with ICP‐MS in A549 cells and A431 cells, up to 0.51 ± 0.03 µg Pt/million cells (Figure 3b; Table S8, Supporting Information), which is more than 100‐fold higher efficiency than that of cisplatin. [ 25 ] This result gives a strong indication that nanoaggregation can significantly improve metallodrug uptake. The A549 cells treated with 5.0 µ m of the platinum complexes for 24 h and imaged by confocal microscopy showed strong deep‐red phosphorescence in the 650–750 nm region under 638 nm excitation, which suggested that emissive nanoaggregates similar to those observed in cell‐free conditions, are also formed inside the cancer cells (Figure 3c).…”

Supramolecular Cylinders Target Bulge Structures in the 5′ UTR of the RNA Genome of SARS‐CoV‐2 and Inhibit Viral Replication**

“…These helicate cylinders are currently the only metallosupramolecular architectures that have been demonstrated to thread through RNAbulge and junction structures,but there is ag rowing interest in metallo-supramolecular designs to bind nucleic acid structures. [53,54] While the SHAPE experiments provide further demonstrations of cylinder selectivity for junctions and bulges over other nucleic acid structures,an exciting possibility is that cylinders might also be able to bind host-cell RNAs tructures,m achinery on which the virus depends for replication, causing ad ual anti-proliferation effect. Ther esults herein suggest that nucleic acid binding metallo-supramolecular architectures,a nd the cylinder designs in particular, merit further exploration as anti-viral agents.…”