Molecular “light switch” for G-quadruplex DNA: cycling the switch on and off

Shi, Shuo; Zhao, Juan; Gao, Xing; Lv, Chunyan; Yang, Li; Hao, Jian Guo; Huang, Hailiang; Yao, Jingyu; Sun, Wenliang; Yao, Tianming; Ji, Liang‐Nian

doi:10.1039/c2dt30076a

Cited by 40 publications

(44 citation statements)

References 61 publications

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“…It has been previously shown that G-quadruplexb inders can stack on the surface of both terminal G-quartet planes. [10][11][12][13][14][15] Both complexes 1 and 2 contain asquare p-aromatic surface, the dppzi ligand preferred to stacki nt he center of at erminal G-quartet end. For the antiparallel basket G-quadruplex structure, both the diagonal and the parallel loop bindingp ositions were considered.…”

Section: Calculation Studiesmentioning

confidence: 99%

“…Recently, our laboratory found that [Ru(L) 2 (dppz)] 2+ (L=2,2′‐bipyridine or 1,10‐phenanthroline) can serve as a prominent molecular “light switch” for both G‐quadruplexes and the i‐motif, which prefers binding G‐quadruplexes over the i‐motif 12. Furthermore, we reported the first example of a reversible G‐quadruplex DNA “light switch”, the switch can be cycled through the competition of [Fe(CN) 6 ] 4− ions and G‐quadruplex DNA 13. We also discovered that the conformation of G‐quadruplex DNA can be regulated by adjusting the pH value in the acidic region, thereby accounting for the on‐off‐on “light‐switch” effect 14.…”

Section: Introductionmentioning

confidence: 98%

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Effect of the Ancillary Ligands on the Spectral Properties and G‐Quadruplexes DNA Binding Behavior: A Combined Experimental and Theoretical Study

Shi

Gao

Huang

et al. 2015

Chemistry A European J

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In an effort to explore the effect of ancillary ligands on the spectral properties and overall G-quadruplex DNA binding behavior, two new ruthenium(II) complexes [Ru(phen)2 (dppzi)](2+) (1) and [Ru(dmp)2 (dppzi)](2+) (2) (phen=1,10-phenanthroline, dmp=2,9-dimethyl-1,10-phenanthroline, dppzi=dipyrido[3,2-a:2',3'-c]phenazine-10,11-imidazole) were prepared. Complex 1 can emit luminescence in the absence and presence of G-quadruplexes DNA. However, with -CH3 substituent on the 2- and 9-positions of the phen ancillary ligand, no detectable luminescence is observed for complex 2 in any organic solvent or in the absence and/or presence of G-quadruplex DNA. Experimental and molecular docking studies indicated that both complexes interacted with the human telomeric repeat AG3(T2AG3)3 (22AG) G-quadruplex with the stoichiometric ratio of 1:1, but the two complexes showed different G-quadruplex DNA binding affinity. Complex 1 binds to the G-quadruplexes DNA more tightly than complex 2 does. Our results demonstrate that methyl groups on the phen ancillary ligand significantly affect the spectral properties and the overall DNA binding behavior of the complexes. Such difference in spectral properties and DNA binding affinities of these two complexes can be reasonably explained by DFT/TD-DFT calculations. This work provides guidance not only on exploring the G-quadruplexes DNA binding behavior of complexes, but also understanding the unique luminescence mechanism.

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Section: Calculation Studiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Effect of the Ancillary Ligands on the Spectral Properties and G‐Quadruplexes DNA Binding Behavior: A Combined Experimental and Theoretical Study

Shi

Gao

Huang

et al. 2015

Chemistry A European J

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“…Ruthenium(II) complexes have been reported to be G‐quadruplex stabilisers21–25 and probes 26–29. Ruthenium(II) complexes, especially dinuclear ruthenium(II) complexes, offer substantial advantages over organic compounds,30–35 other metal complexes (Pt, Ni, etc.…”

Section: Introductionmentioning

confidence: 99%

Dinuclear Ruthenium(II) Complexes That Induce and Stabilise G‐Quadruplex DNA

Chen

et al. 2015

Chemistry A European J

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A series of dinuclear ruthenium(II) complexes were synthesised, and the complexes were determined to be new highly selective compounds for binding to telomeric G-quadruplex DNA. The interactions of these complexes with telomeric G-quadruplex DNA were studied by using circular dichroism (CD) spectroscopy, fluorescence resonance energy transfer (FRET) melting assays, isothermal titration calorimetry (ITC) and molecular modelling. The results showed that the complexes 1, 2 and 4 induced and stabilised the formation of antiparallel G-quadruplexes of telomeric DNA in the absence of salt or in the presence of 100 mM K(+)-containing buffer. Furthermore, complexes 1 and 2 strongly bind to and effectively stabilise the telomeric G-quadruplex structure and have significant selectivity for G-quadruplex over duplex DNA. In comparison, complex 3 had a much lesser effect on the G-quadruplex, suggesting that possession of a suitably sized plane for good π-π stacking with the G-quadruplets is essential for the interaction of the dinuclear ruthenium(II) complexes with the G-quadruplex. Moreover, telomerase inhibition by the four complexes and their cellular effects were studied, and complex 1 was determined to be the most promising inhibitor of both telomerase and HeLa cell proliferation.

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“…20,21 We have modified the main ligand of [Ru(phen) 2 dppz] 2+ (1) and obtained two similar structured complexes, however, their luminescence properties underwent tremendous changes. For instance, by attaching an imidazole ring to the dppz ligand, complex 2 had an enlarged the π-extended planar, but in the presence of DNA or in aprotic solvent, its luminescence intensity had no significantly growth compared to [Ru(phen) 2 dppz] 2+ (1).…”

Section: Introductionmentioning

confidence: 99%

Impacts of terminal modification of [Ru(phen)₂dppz]²⁺on the luminescence properties: a theoretical study

et al. 2015

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[Ru(phen)2dppz](2+) and other closely related ruthenium(II) complexes containing π-extended ligands were found to be non or weakly emissive in water, while exhibiting significant luminescence intensity growth when bound to DNA, however, a satisfactory interpretation has not been provided on this "light switch" mechanism. In the present study, we investigated the vertical transitions and triplet excited states of [Ru(phen)2dppz](2+) (1), [Ru(phen)2dppzi](2+) (2) and [Ru(phen)2dppz-idzo](2+) (3) in the gas phase and aqueous solution, through time dependent-density functional theory (TDDFT). Based on the optimized (3)MLCT and (3)LLCT structures and energies, we found that the (3)MLCT state might be responsible for the emissions of the complexes. Interesting connections between the singlet vertical transitions and the luminescence properties were noticed. Through ZORA-TDDFT calculation with perturbative SOC, we evaluated the intersystem crossing between the lowest singlet excited state, and both (3)MLCT state and (3)LLCT state, which gave a reasonable explanation for the luminescence properties of these complexes.

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Molecular “light switch” for G-quadruplex DNA: cycling the switch on and off

Abstract: We report a new G-quadruplex DNA "light switch", where the light switch can be cycled on and off through the successive introduction of G-quadruplex DNA and [Fe(CN)(6)](4-) ions.

Cited by 40 publications

References 61 publications

Effect of the Ancillary Ligands on the Spectral Properties and G‐Quadruplexes DNA Binding Behavior: A Combined Experimental and Theoretical Study

Effect of the Ancillary Ligands on the Spectral Properties and G‐Quadruplexes DNA Binding Behavior: A Combined Experimental and Theoretical Study

Dinuclear Ruthenium(II) Complexes That Induce and Stabilise G‐Quadruplex DNA

Impacts of terminal modification of [Ru(phen)₂dppz]²⁺on the luminescence properties: a theoretical study

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Molecular “light switch” for G-quadruplex DNA: cycling the switch on and off

Abstract: We report a new G-quadruplex DNA "light switch", where the light switch can be cycled on and off through the successive introduction of G-quadruplex DNA and [Fe(CN)(6)](4-) ions.

Cited by 40 publications

References 61 publications

Effect of the Ancillary Ligands on the Spectral Properties and G‐Quadruplexes DNA Binding Behavior: A Combined Experimental and Theoretical Study

Effect of the Ancillary Ligands on the Spectral Properties and G‐Quadruplexes DNA Binding Behavior: A Combined Experimental and Theoretical Study

Dinuclear Ruthenium(II) Complexes That Induce and Stabilise G‐Quadruplex DNA

Impacts of terminal modification of [Ru(phen)2dppz]2+on the luminescence properties: a theoretical study

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Impacts of terminal modification of [Ru(phen)₂dppz]²⁺on the luminescence properties: a theoretical study