Electron Transfer in DNA from Guanine and 8-Oxoguanine to a Radical Cation of the Carbohydrate Backbone

Abstract

Photolysis of a 4'-pivaloyl-substituted nucleotide in single- and double-stranded DNA (1) generated an enol ether radical cation 4 that was reduced to enol ether 17 by electron transfer from the nearest guanoside (G). Variation of the nucleotide sequence demonstrated a strong distance dependence of this electron-transfer rate with beta = 1.0 +/- 0.1 A(-1). When 8-oxoguanosine (G(oxo)) was used as the electron donor, the rate of the electron transfer increased by a factor of 4 but the distance dependence of the transfer remained unchanged within experimental error. In single strands, the number of intervening A, T, and C nucleotides had a much smaller effect; the rate remained nearly constant for two, three, or four intervening nucleotides. This is explained by the flexibility of the single-stranded oligonucleotides.

Electron transfer reactions of rigid, cofacially compressed, π-stacked porphyrin–bridge–quinone systems

“…As underscored by the extensive literature in the area [124][125][126]129,165,[172][173][174][175][176][177][178][179][180][181][182][183][184][185][186][187][189][190][191][192][193][194][195][196][197], the popularity of double-stranded DNA and related nucleobase scaffolds for interrogating issues pertinent to stacked manifold electronic coupling derives largely from their ease of synthesis. Fabrication ofstacked assemblies, in which interactions between cofacially aligned D, Sp, and A moieties differ radically from deoxyribonucleic acid-based systems, is inherently more challenging.…”

“…In the late 1980s, Barton pioneered the use of double-stranded DNA as a template to interrogate electronic coupling through stacked, -cofacial assemblies . Giese [192][193][194][195][196][197], Lewis and Wasielewski [180][181][182][183][184][185][186][187], Schuster [172][173][174][175][176], Meade [177][178][179], Beratan [124][125][126]129], Tanaka [189,190] and Fukui [189][190][191], and Ratner [165,[216][217][218][219][220] have since investigated a wide range of mechanistic issues related to DNA-mediated charge transport. ET assemblies that utilize double-stranded DNA as the Sp separating D from A define model assemblies with which to probe electronic coupling mediated by -cofacial aromatic units.…”

The Influence of Mismatches on Long-Distance Charge Transport through DNA

“…). [7] For analytical reasons we used double strands in which the charge was transferred to a G of the 32 P-labeled complementary strand (2 33). This G .…”

Metabolic Photofragmentation Kinetics for a Minimal Protocell: Rate-Limiting Factors, Efficiency, and Implications for Evolution

“…Recently, bio-related molecules that may be used as information molecules, such as peptide, DNA, or peptide nucleic acid (PNA), have been demonstrated to be excellent electron relay systems [2,5,10,11,15,21]. Since the efficiency of charge transfer is sequence-dependent, we can use certain sequences of DNA or PNA strands as an electron relay system to control the fragmentation reaction efficiency.…”