✍ Scribed by Mark W. Grinstaff
No coin nor oath required. For personal study only.
The biological role of deoxyribonucleic acid (DNA) is to store and code genetic information. This unique biopolymer consists of a double helix with major and minor grooves. An aromatic p-stack core runs throughout the structure where the bases of the pyrimidine deoxynucleotides (thymidine, T; cytidine, C) and purine deoxynucleotides (adenosine, A; guanosine, G) participate in Watson ± Crick base pairing (A:T; C:G). Although first posed in the 1960s, the question of how charged species can be transported over short or long distance in DNA is still debated. [3±8] An intense worldwide research effort is underway to explain the large variations in observed electron transfer rates (microsecond to picosecond) and to develop well-defined chemical systems for further study.
Radiation, carcinogens, and metabolic waste products can damage DNA, and, if left unrepaired by the normal cellular machinery, these damages can lead to mutations and carcinogenesis with grave health consequences. [9±17] Further analysis reveals many of these damages to be a result of selective radical reactions with guanine bases, consistent with the relative ease with which guanine is oxidized compared to adenine, cytosine, and thymine. [18±23] A study of electron transfer and radical-cation migration in DNA as well as identification of the factors that control the rates of these processes will provide valuable information for understanding DNA damage in vivo and insight into the mechanism of charge transfer through different media. A greater understanding of DNA-mediated electron transfer may have an additional clinical impact through the development of novel diagnostic tools for screening nucleic acids, proteins, or carcinogens.
Although significant advances in the study of charge transport in DNA have been reported within the last five years, [7, 24±26] a number of issues remain unresolved. Current studies address multiple factors affecting this process such as oligonucleotide sequence, base pairing, p stacking, and duplex structure as well as the donor ± acceptor distance, the labeling site, and the dynamics. In contrast to-electron transfer
📜 SIMILAR VOLUMES