The central component of all self-replicating molecular machinery alive today is the molecule known as Deoxyribonucleic acid (DNA). The molecular structure of DNA that allows it to translate, transcribe and copy information was first described by Watson and Crick in 1953 when they ended their Nature paper with the following understatement:
"It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material." [1]
50 years of extrapolation on that idea have led to some of the greatest medical advances in history, leading eventually to the Human Genome Project. Considering that, imagine what the last 50 years may have brought had that sentence read: "It has not escaped our notice that the aromatic stacking that we have postulated immediately suggests a possible mechanism for nanoelectronic circuits."
The idea of charge transfers through DNA was indeed proposed in the years following 1953. However, since the electronic properties of DNA were not easily determined, it took about 40 years for the first experimental evidence of DNA mediated charge transfers to be published[2]. Early skepicism claiming that the charge transfers occured though the backbone, or even through the surrounding solution have since been quenched by data showing that strong stacking within the double helix results in the fastest electron-transfer kinetics[3]. Further research on electron transfers in DNA have indicated that the DNA sequence has predictable effects on the conductance of the ubiquitous biopolymer. Thus, depending on the sequence of the stretch of DNA propagating the electron transfer, DNA can either act as a conductor, a semiconductor, or an insulator [4]. Most of the medically funded research on DNA mediated charge transfers focus on understanding how damaged DNA is repaired. For instance, when ionizing radiation or UV light strikes DNA, radicals can be formed within the DNA that may travel long distances before covalently binding atoms that are not normally connected[5]. Studies involving both naturally occurring repair enzymes and mutagenically designed proteins are currently underway.
Next Page > DNA Mediated Energy Transfer - Page II > Page 1, 2.
References
[1]J. D. Watson, F. H. C. Crick, A structure for Deoxyribose Nucleic Acid, Nature, 171, 737 (1953).Full Text - html
[2]C. J. Murphy, M. R. Arkin, Y. Jenkins, N. D. Ghatlia, S. Bossmann, N. J. Turro and J. K. Barton, Long Range Photoinduced Electron Transfer through a DNA Helix, Science, 262, 1025 (1993). Abstract; Homepage
[3]S. O. Kelley, J. K. Barton, Electron Transfer Between Bases in Double Helical DNA, Science, 283, 375 (1999).Supplimentary Material
[4] B. Giese, S. Wessely, M. Spormann, U. Lindemann, E. Meggers, M. E. Michel-Beyerle, On the Mechanism of Long-Range Electron Transfer through DNA, Angew. Chem. Int. Ed. Engl. 38, 996 (1999).
No. 7 1999 Contents
[5]M. E. Nunez, D. B. Hall and J. K. Barton, Long Range Oxidative Damage to DNA: Effects of Distance and Sequence, Chemistry and Biology, 6, 85 (1999). Abstract
[6]R. E. Holmlin, P. J. Dandliker, J. K. Barton, Angew. Chem. Int. Ed. Engl., 36, No. 24, 2714-2730 (1997).; Angew. Chem. 109, 2830 (1997). Review
.Keywords: DNA mediated energy transfer self-replicating biomolecular nanotechnology molecular machinery nanoelectronic deoxyribonucleic acid sequence information Watson Crick 1953 Nature electron-transfer kinetics helix stacking charge conductance conductor semiconductor insulator repair enzymes mutagenesis protein design
