Distance-Dependent Electron Transfer in DNA Hairpins

• Published in: Science (American Association for the Advancement of Science) Vol. 277; no. 5326; pp. 673 - 676
• Main Authors: Lewis, Frederick D., Wu, Taifeng, Zhang, Yifan, Letsinger, Robert L., Greenfield, Scott R., Wasielewski, Michael R.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 01.08.1997; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Absorption spectra; Analytical, structural and metabolic biochemistry; Anions; Base Composition; Biological and medical sciences; Chemistry; Coordination chemistry; Deoxyribonucleic acid; DNA; DNA - chemistry; Dna, deoxyribonucleoproteins; Donors; Electron transfer; Electrons; Family (Sociological Unit); Fluorescence; Fundamental and applied biological sciences. Psychology; Kinetics; Light; Line spectra; Measurement; Models, Molecular; Nucleic Acid Conformation; Nucleic acids; Observation; Organic Chemistry; Oxidation-Reduction; Oxidation-reduction reaction; Oxidation-reduction reactions; Singlet state; Spectrometry, Fluorescence; Spectrum Analysis; Stilbenes; Stilbenes - chemistry; Hairpin loop; Synthetic product; Photoinduction; DNA; Luminescence quenching; Electron transfer; Carboxamide; Oligonucleotide; Physicochemical properties; Stilbene derivatives
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.277.5326.673

The distance dependence of photoinduced electron transfer in duplex DNA was determined for a family of synthetic DNA hairpins in which a stilbene dicarboxamide forms a bridge connecting two oligonucleotide arms. Investigation of the fluorescence and transient absorption spectra of these hairpins established that no photoinduced electron transfer occurs for a hairpin that has six deoxyadenosine-deoxythymidine base pairs. However, the introduction of a single deoxyguanosine-deoxycytidine base pair resulted in distance-dependent fluorescence quenching and the formation of the stilbene anion radical. Kinetic analysis suggests that duplex DNA is somewhat more effective than proteins as a medium for electron transfer but that it does not function as a molecular wire.