Journal ArticleDOI
Proton Transfer of Guanine Radical Cations Studied by Time-Resolved Resonance Raman Spectroscopy Combined with Pulse Radiolysis
TLDR
The oxidation of guanine (G) is studied by using transient absorption and time-resolved resonance Raman spectroscopies combined with pulse radiolysis to demonstrate the pH dependence and the increase in the bonding order of pyrimidine (Pyr) and imidazole rings.Abstract:
The oxidation of guanine (G) is studied by using transient absorption and time-resolved resonance Raman spectroscopies combined with pulse radiolysis. The transient absorption spectral change demonstrates that the neutral radical of G (G•(−H+)), generated by the deprotonation of G radical cation (G•+), is rapidly converted to other G radical species. The formation of this species shows the pH dependence, suggesting that it is the G radical cation (G•+)′ formed from the protonation at the N7 of G•(−H+). On one hand, most Raman bands of (G•+)′ are up-shifted relative to those of G, indicating the increase in the bonding order of pyrimidine (Pyr) and imidazole rings. The (G•+)′ exhibits the characteristic CO stretching mode at ∼1266 cm–1 corresponding to a C–O single bond, indicating that the unpaired electron in (G•+)′ is localized on the oxygen of the Pyr ring.read more
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Direct Observation of the Hole Carriers in DNA Photoinduced Charge Transport.
Michelle A. Harris,Ashutosh Kumar Mishra,Ryan M. Young,Kristen E. Brown,Michael R. Wasielewski,Frederick D. Lewis +5 more
TL;DR: The dynamics of each step in the charge separation and charge recombination process as well as the overall efficiency of charge separation have been determined, thus providing a complete account of the mechanism and dynamics of photoinduced charge transport in these DNA hairpins.
Journal ArticleDOI
Pulse Radiolysis Studies for Mechanism in Biochemical Redox Reactions
TL;DR: Pulse radiolysis is a powerful method for generating highly reduced or oxidized species and free radicals, and studies of the reactions between specific radicals and solutes, often revealing the mechanisms underlying the initial and subsequent reactions.
Journal ArticleDOI
Tracking Photoinduced Charge Separation in DNA: from Start to Finish.
TL;DR: Evidence is obtained based on femtosecond transient absorption spectroscopy for the formation of delocalized A-polarons in A-tracts possessing four or more A-T base pairs, used to track hole transport across less-common DNA structures.
Journal ArticleDOI
UV–Vis Action Spectroscopy of Guanine, 9-Methylguanine, and Guanosine Cation Radicals in the Gas Phase
TL;DR: Action spectroscopy allowed us to assign the canonical 6-oxo structure (rG1•+) to the gas-phase guanosine cation radicals that were formed as the lowest-energy tautomers.
References
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