Photophysics of 2'-Deoxyuridine (dU) Nucleosides Covalently Substituted with Either 1-Pyrenyl or 1-Pyrenoyl: Observation of Pyrene-to-Nucleoside Charge-Transfer Emission in 5-(1-Pyrenyl)-dU

Netzel, Thomas L.; Zhao, Min; Nafisi, Kambiz; Headrick, Jeb; Sigman, Matthew S.; Eaton, Bruce E.

doi:10.1021/ja00141a002

Cited by 113 publications

(120 citation statements)

References 10 publications

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“…[37] They established the following order for the quenching efficiencies: A < G < T < C. Emission spectra and lifetime measurements provided evidence for electron transfer from Py* to the pyrimidine bases C or T. This charge transfer assignment has been proven by nanosecond fluorescence lifetime measurements with 5-(pyren-1-yl)-2'-deoxyuridine (Py-dU). [38] Most recently, our group prepared Py-dU and 5-(pyren-1-yl)-2'-deoxycytidine (Py-dC) by Suzuki-Miyaura cross-coupling reactions. [39] Subsequently, the properties and dynamics of the intramolecular electron transfer in Py-dU and Py-dC were characterized by steady-state fluorescence spectroscopy and femtosecond transient absorption spectroscopy in water at different pH values( Figure 5).…”

Section: Methodsmentioning

confidence: 99%

Reductive Electron Transfer and Transport of Excess Electrons in DNA

Wagenknecht

2003

Angew Chem Int Ed

146

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In principle, DNA-mediated charge transfer processes can be categorized as either oxidative hole transfer or reductive electron transfer. In research on DNA damage, major efforts have focused on the investigation of oxidative hole transfer or transport, resulting in insights on the mechanisms. On the other hand, the transport or transfer of excess electrons has a large potential for biomedical applications, mainly for DNA chip technology. Yet the mechanistic details of this type of charge transfer chemistry were unclear. In the last two years this mechanism has been addressed in gamma-pulse radiolysis studies with randomly DNA-bound electron acceptors or traps. The major disadvantage of this experimental setup is that the electron injection and trapping is not site-selective. More recently, new photochemical assays for the chemical and spectroscopic investigation of reductive electron transfer and electron migration in DNA have been published which give new insights into these processes. Based on these results, an electron-hopping mechanism is proposed which involves pyrimidine radical anions as intermediate electron carriers.

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Section: Methodsmentioning

confidence: 99%

Reductive Electron Transfer and Transport of Excess Electrons in DNA

Wagenknecht

2003

Angew Chem Int Ed

146

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“…Diese Zuordnung des Ladungstransfers wurde zuvor durch Nanosekunden-zeitaufgelöste Messungen der Fluoreszenzlebensdauer von 5-(Pyren-1-yl)-2'-desoxyuridin (Py-dU) überprüft. [38] Kürzlich wurden von unserer Gruppe Py-dU und 5-(Pyren-1-yl)-2'-desoxycytidin (Py-dC) über Suzuki-MiyauraKreuzkupplungsreaktionen hergestellt [39] und die Eigenschaften und die Dynamik des intramolekularen Elektronentransfers in Py-dU und Py-dC durch stationäre Fluoreszenzspektroskopie und Femtosekunden-zeitaufgelöste transiente Absorptionsspektroskopie in Wasser bei unterschiedlichen pHWerten charakterisiert (Abbildung 5). [40] Der Vergleich von Py-dU mit Py-dC als Nucleosid-Modelle für den Elektronentransfer in der DNA zeigt, dass ein kleiner Energieunterschied zwischen UC À und CC À existiert, was in Einklang ist mit den in den vorherigen Abschnitten vorgestellten Rechnungen und Experimenten.…”

Section: Photochemische Studienunclassified

Reduktiver Elektronentransfer und Transport von Überschusselektronen in DNA

Wagenknecht

2003

Angewandte Chemie

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DNA‐vermittelte Ladungstransferprozesse lassen sich prinzipiell in oxidative Lochtransferprozesse und reduktive Elektronentransferprozesse einteilen. Im Hinblick auf die Entstehung von DNA‐Schäden lag das Hauptaugenmerk bisheriger Forschung auf der Untersuchung des oxidativen Lochtransfers oder ‐transportes. Daraus wurden wichtige Informationen beispielsweise über den Mechanismus erhalten. Dagegen hat der Transport oder Transfer von Überschusselektronen ein großes Potenzial für biomedizinische Anwendungen, hauptsächlich in der DNA‐Chiptechnologie. Zur Untersuchung der mechanistischen Details wurden in γ‐Puls‐Radiolyse‐Studien Elektronenacceptoren eingesetzt , die nicht kovalent an DNA gebunden sind. Der entscheidende Nachteil dieses experimentellen Aufbaus liegt darin, dass sowohl die Injektion als auch das Abfangen der Elektronen nicht regiospezifisch erfolgen kann. Kürzlich wurden neue photochemische DNA‐Systeme publiziert, die eine chemische und spektroskopische Untersuchung des reduktiven Elektronentransfers sowie der Wanderung von Überschusselektronen in der DNA erlauben. Basierend auf diesen Resultaten wurde ein Elektronen‐Hopping‐Mechanismus vorgeschlagen, bei dem die Pyrimidin‐Radikalanionen als intermediäre Elektronenträger auftreten.

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“…They have proven useful in the context of recognition and as molecular probes, [6][7][8][9][10][11][12][13] electron injection, [14,15] bioengineering, [16,17] structure stabilisation [18] and structure determination [19][20][21][22][23] as well as nucleobase photophysics. [24,25] Their relatively high quantum efficiency, sensitivity to environmental factors [26,27] and capability to form excimers have opened many possibilities in the field of DNA and RNA hybridisation studies.…”

Section: Introductionmentioning

confidence: 99%

2‐(1‐Ethynylpyrene)‐Adenosine as a Folding Probe for RNA—Pyrene in or out

et al. 2010

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A series of short RNA duplexes containing one or two 1-ethynylpyrene-modified adenine bases was synthesised. The melting behaviour of these duplexes was examined by monitoring temperature-dependent pyrene fluorescence. In the singly modified RNA duplexes, the bases flanking the ethynylpyrene-rA were varied to examine the sequence specificity of the fluorescence change of pyrene upon RNA hybridisation. Because an increase in pyrene fluorescence upon melting of the duplex can be correlated with intercalation of pyrene, and a decrease is usually associated with the position of pyrene outside the strand, a relationship between the flanking bases and the tendency of the dye to intercalate has been established. It was found that pyrene intercalation is less likely to take place if the modified base is flanked only by A-U base pairs. Flanking G-C base pairs, even only in the 5'-direction of the modified base, will favour intercalation. In addition, we examined a doubly modified compound that had a pyrene located on each strand. The spectra indicated that the two pyrenes were close enough for interaction. Upon melting of the strand, a fluorescence blue shift corresponding to the dissociation of the pyrene-pyrene complex could be observed in addition to the intensity effect already known from the singly modified compounds. Two melting curves based on the different properties of the fluorophore could be extracted, leading to different melting points corresponding to the global duplex melting and to the change of local pyrene environment, respectively.

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Photophysics of 2'-Deoxyuridine (dU) Nucleosides Covalently Substituted with Either 1-Pyrenyl or 1-Pyrenoyl: Observation of Pyrene-to-Nucleoside Charge-Transfer Emission in 5-(1-Pyrenyl)-dU

Cited by 113 publications

References 10 publications

Reductive Electron Transfer and Transport of Excess Electrons in DNA

Reductive Electron Transfer and Transport of Excess Electrons in DNA

Reduktiver Elektronentransfer und Transport von Überschusselektronen in DNA

2‐(1‐Ethynylpyrene)‐Adenosine as a Folding Probe for RNA—Pyrene in or out

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