Long-range charge transport through double-stranded DNA mediated by manganese or iron porphyrins
- 85 Downloads
Guanine oxidation by electron transfer results in the formation of a guanine radical cation, which is at the origin of long-range charge transport through double-stranded DNA. It is possible to observe guanine lesions at a long distance from the oxidative reagent covalently bound to DNA owing to the migration of the positive hole in the DNA π-stacks. This phenomenon of long-range hole transport is classically studied in the literature with photosensitizers used as one-electron oxidants. It is shown in the present work that the process of long-range charge transport and the concomitant formation of guanine lesions at a long distance can be observed also in the case of two-electron oxidants. This is the signature of the formation of a transient guanine radical cation in the course of the two-electron abstraction process and consequently evidence of the separated one plus one electron abstraction steps. Long-range charge transport is likely to be a universal mechanism for any two-electron oxidant acting by electron abstraction provided that the second electron abstraction is slower than hole transfer.
KeywordsManganese Iron Porphyrin DNA Guanine oxidation
A NATO Science Fellowship to M.M. is gratefully acknowledged. The authors thank Bernard Meunier for fruitful discussion.
- 17.Meunier B, Robert A, Pratviel G, Bernadou J (2000) In: Kadish KM, Smith K, Guilard R (eds) Handbook of porphyrins and related macrocycles, vol 4. Academic Press, San Diego, pp 119–187Google Scholar
- 28.Mestre B, Nascimben S, Pratviel G, Meunier B (1998) C R Acad Sci II 1:725–736Google Scholar
- 30.Bigey P, Pratviel G, Meunier B (1995) J Chem Soc Chem Commun 181–182Google Scholar
- 31.Fasman GD (1975) Handbook of biochemistry and molecular biology—nucleic acids. 3rd edn. CRC Press, Boca RatonGoogle Scholar
- 33.Bigey P, Frau S, Loup C, Claparols C, Bernadou J, Meunier B (1996) Bull Soc Chim 133:679–689Google Scholar