Remote Photodamaging of DNA by Photoinduced Energy Transport

How far does energy migrate in DNA? DNA-mediated energy transport is a new pathway to DNA photodamage occurring at remote sites and not locally at the site of excitation by light. Although these distances might be small with regard to a whole gene, the proposal that a site might be damaged other than the site of initial photoexcitation is important to the understanding of mutations that are caused by remote DNA photodamages.
Local DNA photodamaging by light is well-studied and leads to a number of structurally identified direct damage, in particular cyclobutane pyrimidine dimers, and indirect oxidatively generated damage, such as 8-oxo-7,8-hydroxyguanine. Similar damages have now been found at remote sites, at least more than 105 Å (30 base pairs) away from the site of photoexcitation. In contrast to the established mechanisms of local DNA photodamaging, the processes of remote photodamage are only partially understood. Known pathways include those to remote oxidatively generated DNA photodamages, which were elucidated by studying electron hole transport through the DNA about 20 years ago. Recent studies with DNA photosensitizers and mechanistic proposals on photoinduced DNA-mediated energy transport are summarized in this minireview. ... mehrThese new mechanisms to a new type of remote DNA photodamaging provide an important extension to our general understanding to light-induced DNA damage and their mutations.