DNA, electron transfer

In solid state materials, single-step electron transport between dopant species is well known. For example, electron-hole recombination accounts for luminescence in some materials [H]. Multistep hopping is also well known. Models for single and multistep transport are enjoying renewed interest in tlie context of DNA electron transfer [12, 13, 14 and 15]. Indeed, tliere are strong links between tire ET literature and tire literature of hopping conductivity in polymers [16]. 

In addition to conventional applications in conducting polymers and electrooptical devices, a number of recent novel applications have emerged. Switching of DNA electron transfer upon single-strand/double-strand hybridization fonns the basis for a new medical biosensor teclmology. Since the number of base pairs of length 20... 

Barton and coworkers have shown that proteins can in fact modulate the DNA electron transfer [168]. Methyltransferases are enzymes that recognize distinct DNA sequences, e.g., 5 -G CGC-3, and effect methylation by extrading the target base cytosine ( C) completely out of the DNA duplex while the remainder of the double helix is left intact. The methyltransferase Hha 1-DNA complex is a well-characterized example, revealing that the structure of the DNA is significantly but locally distorted [169,170]. In a recent study, Raj ski et al. used DNA duplex 20 containing the M.Hha I binding site between two oxidizable 5 -GG-3 sites [168] (Fig. 20). The duplex contains a complementary strand, selectively 5 -modified with a Rh intercalator that can function as a photooxidant. Upon... 

FIG. 20 DNA duplex 20 used for studies regarding the protein-modulated DNA electron transfer. Methyltransferase M.Hhal is capable of binding to the shadowed recognition site between two oxidizable 5 -GG-3 sites (outlined letters). The complementary strand of the duplex contains the Rh intercalator, [Rh(phi)2bpy ], at its 5 end, which can function as a photooxidant. (Adapted from Ref. 168.)... 

Keywords DNA Electron transfer Hole injection Hole transport Transient absorption ... 

BerUn YA, Kurnikov IV, Beratan D, Ratner MA, Burin AL (2004) DNA Electron Transfer Processes Some Theoretical Notions. 237 1-36... 

DNA Electron Transfer Processes Some Theoretical Notions... 

Rajski SR, Kumar S, Robert RJ, Barton JK. Protein-modulated DNA electron transfer. JAm Chem Soc 1999 121 5615-16. 

Keywords Charge transfer, DNA, Electron transfer, HOMO-level... 

The three-state (three-potential-energy surface) problem is of interest for redox chains, chemical triad model systems, DNA electron transfer, and the primary charge separation in photosynthesis. As there are two energy-gap fluctuations in these reactions, and the fluctuations are not simply related to each other (in contrast to the case of two-electron transfer in two-center systems, vide infra), the problem is intrinsically two-dimensional. Marchi et al. [54], Zusman and Beratan [55], and Okada and Bandyopadhyay [56] have analyzed the nature of these potential energy surfaces and the electron-transfer kinetics. In the steady-state approximation for species 2,... 

To me the key to DNA electron transfer is this base-pair stacking. Our intercalators were also well stacked and so represented effective probes of... 

Our DNA is constantly being damaged. But we also have quite effective DNA repair machinery. It turns out, however, that we don t actually understand, in 1999, how this repair machinery operates, how the damage is sensed. Maybe nature exploits DNA electron transfer chemistry. How these repair proteins find the damage in our DNA, how they recognize... 

Berlin Y.A., Beratan D., Kurnikov I.V., Ratner M.A., Burin A.L, DNA electron transfer processes Some theoretical notions,Top Curr. Chem., 2004,237,1-36. 

Yuri A. Berlin, Ogor V. Kurnikov, David Bertran, Mark A. Ratner, and Alexander L. Burin, DNA electron transfer processes Some theoretical notions. Topics in Current Chemistry, 237, 1-36 (2004). 

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