Radiation-induced charge transfer in DNA

There is significant evidence that direct energy deposition in DNA results in radiation-induced charge transfer in DNA as discussed in section 4.2. Direct energy deposition may lead to ionisation of the DNA as shown in reaction (16). 

Photo-induced charge migration in DNA Distance dependence 

In equation (17), the rate constant for electron turmelling is ket, R the distance between donor and acceptor and P a distance dependent constant. This electron tunnelling type of mechanism indicates that the rate of electron transfer decreases by about one order of magnitude per base pair, since the typical value of p is in the range 1-1.5 A [123]. As shown in Table 4 typical values of P for 

DNA acting as a medium to facilitate charge transfer. The distance of charge transfer on the whole is probably limited otherwise the fingerprint of the radiation track, especially at high LET, would be lost and consequently the enhanced radiosensitivity of high LET radiation. The two types of clustered DNA damage discussed are 

This work is supported by the Medical Research Council. I am grateful to my colleagues past and present who have contributed significantly to research on radiation induced DNA damage. I thank Anne Johnson and Jon Fulford for help in compilation of this chapter. 

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