Hole Trapping of G‐Quartets in a G‐Quadruplex

Choi, Jungkweon; Park, Jong Jin; Tanaka, Atsushi; Park, Man Jae; Jang, Yoon Jung; Fujitsuka, Mamoru; Kim, Seog K.; Majima, Tetsuro

doi:10.1002/anie.201208149

Cited by 51 publications

(65 citation statements)

References 47 publications

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“…It has been however shown that DNA sequences containing consecutive guanines are better electron‐donating sites in B‐DNA than isolated guanines . According to a recent report, the oxidation potential of guanines in G4 structures should be significantly lower than that of two or three stacked guanines . Accordingly, the driving force for electron transfer in Tel21 should increase.…”

Section: Resultscontrasting

confidence: 60%

Ultrafast Electron Transfer in Complexes of Doxorubicin with Human Telomeric G‐Quadruplexes and GC Duplexes Probed by Femtosecond Fluorescence Spectroscopy

et al. 2016

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Doxorubicin (DOX) is a natural anthracycline widely used in chemotherapy; its combined application as a chemotherapeutic and photodynamic agent has been recently proposed. In this context, understanding the photoinduced properties of DOX complexes with nucleic acids is crucial. Herein, the study of photoinduced electron transfer in DOX-DNA complexes by femtosecond fluorescence spectroscopy is reported. The behaviour of complexes with two model DNA structures, a G-quadruplex (G4) formed by the human telomeric sequence (Tel21) and a d(GC) duplex, is compared. The DOX affinity for these two sequences is similar. Although both 1:1 and 2:1 stoichiometries have been reported for DOX-G4 complexes, only 1:1 complexes form with the duplex. The steady-state absorption indicates a strong binding interaction with the duplex due to drug intercalation between the GC base pairs. In contrast, the interaction of DOX with Tel21 is much weaker and arises from drug binding on the G4 external faces at two independent binding sites. As observed for DOX-d(GC) complexes, fluorescence of the drug in the first binding site of Tel21 exhibits decays within a few picoseconds following a biphasic pattern; this is attributed to the existence of two drug conformations. The fluorescence of the drug in the second binding site of Tel21 shows slower decays within 150 ps. These timescales are consistent with electron transfer from the guanines to the excited drug, as favoured by the lower oxidation potential of the stacked guanines of G4 with respect to those in the duplex.

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Section: Resultscontrasting

confidence: 60%

Ultrafast Electron Transfer in Complexes of Doxorubicin with Human Telomeric G‐Quadruplexes and GC Duplexes Probed by Femtosecond Fluorescence Spectroscopy

et al. 2016

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“…Moreover, although HT through GQ with fewer than four layers of G‐tetrads was observed in a variety of G‐rich sequences and through both biochemical and spectroscopic methods, here more efficient HT was shown over a longer GQ bridge. The dendritic DNA design allowed not only the assembly of tetra‐stranded GQ with defined molecular stoichiometry, but also the helical structure of GQ extended to eight layers of G‐tetrads and potentially to longer G‐tetrad stacking.…”

Section: Resultsmentioning

confidence: 85%

“…G‐quadruplexes were revealed as either a charge sink or a conduit in the literature. On one side, Barton's group observed more G radicals in GQ than in duplex DNA by biochemical methods, whereas Majima and co‐workers detected riboflavin next to a thrombin‐binding aptamer, which was reduced by GQ through ultrafast spectroscopy . Both observations showed the oxidation reaction was concentrated on G‐quadruplexes, even in the presence of duplex DNA.…”

Section: Resultsmentioning

confidence: 99%

“…G‐quadruplexes (GQ) are a family of four‐stranded nucleic acid structures folded by guanine‐rich sequences . Although guanine with the lowest oxidation potential among the four natural nucleobases could make GQ a potential charge sink, the stack of G‐tetrads has an extensive aromatic area, which may provide an efficient pathway for charge propagation (Scheme ). However, results from distant photooxidation, ultrafast spectroscopy, and theoretical simulations have shown GQs either as oxidation hotspots or electron conduits.…”

Section: Introductionmentioning

confidence: 99%

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Efficient Long‐Range Hole Transport Through G‐Quadruplexes

Meng

et al. 2017

Chemistry A European J

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DNA offers a means of long-range charge transport for biology and electric nanodevices. Here, a series of tetra-stranded G-quadruplexes were assembled within a dendritic DNA architecture to explore oxidative charge transport (hole transport) through the G-quadruplex. Efficient charge transport was achieved over 28 Å upon UV irradiation. Over a longer G-quadruplex bridge, hole transport was escalated to a higher efficiency, which resulted in a higher yield than that of the optimal duplex DNA for charge transport, that is, the adenine tract. Efficient long-range hole transport suggests tetra-stranded G-quadruplexes, instead of an oxidation hotspot, hold better potential as an electron conduit than duplex DNA.

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“…Electronic conductivity of "non-canonical" DNA forms, quadruplexes in particular have also been addressed, but such reports have only begun to appear much more recently [27][28][29][30][31][32][33] , and with little if any direct approach to interfacial ; (c) surface immobilized G-quadruplexes finally offer perspectives for ultra-sensitive detection of metal ions [40][41][42] , complex biomolecules such as peptides [23][24][25][26][27][28][29][30] , and perhaps other analytes.…”

Section: Resultsmentioning

confidence: 99%