Reference : Base-dependent electron photodetachment from negatively charged DNA strands upon 260-nm ...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Chemistry
http://hdl.handle.net/2268/382
Base-dependent electron photodetachment from negatively charged DNA strands upon 260-nm laser irradiation
English
Gabelica, Valérie mailto [Université de Liège - ULg > Département de Chimie (Sciences) > Chimie physique, spectrométrie de masse >]
Rosu, Frédéric [Université de Liège - ULg > Département de Chimie (Sciences) > Chimie physique, spectrométrie de masse >]
Tabarin, Thibault [Université Lyon 1 et CNRS > > Laboratoire de Spectrométrie Ionique et Moléculaire - LASIM > >]
Kinet, Catherine [Université de Liège - ULg > Département de Chimie (Sciences) > Chimie physique, spectrométrie de masse >]
Antoine, Rodolphe [Université Lyon 1 et CNRS > > Laboratoire de Spectrométrie Ionique et Moléculaire - LASIM > >]
Broyer, Michel [Université Lyon 1 et CNRS > > Laboratoire de Spectrométrie Ionique et Moléculaire - LASIM > >]
De Pauw, Edwin mailto [Université de Liège - ULg > Département de Chimie (Sciences) > Chimie physique, spectrométrie de masse >]
Dugourd, Philippe [Université Lyon 1 et CNRS > > Laboratoire de Spectrométrie Ionique et Moléculaire - LASIM > >]
2007
Journal of the American Chemical Society
American Chemical Society
129
15
4706-4713
Yes (verified by ORBi)
International
0002-7863
1520-5126
Washington
DC
[en] photodetachment ; mass spectrometry ; DNA ; fragmentation ; oxidation ; photochemistry ; anion
[en] DNA multiply charged anions stored in a quadrupole ion trap undergo one-photon electron ejection (oxidation) when subjected to laser irradiation at 260 nm (4.77 eV). Electron photodetachment is likely a fast process, given that photodetachment is able to compete with internal conversion or radiative relaxation to the ground state. The DNA [6-mer](3-) ions studied here show a marked sequence dependence of electron photodetachment yield. Remarkably, the photodetachment yield (dG(6) > dA(6) > dC(6) > dT(6)) is inversely correlated with the base ionization potentials (G < A < C < T). Sequences with guanine runs show increased photodetachment yield as the number of guanine increases, in line with the fact that positive holes are the most stable in guanine runs. This correlation between photodetachment yield and the stability of the base radical may be explained by tunneling of the electron through the repulsive Coulomb barrier. Theoretical calculations on dinucleotide monophosphates show that the HOMO and HOMO-1 orbitals are localized on the bases. The wavelength dependence of electron detachment yield was studied for dG(6)(3-). Maximum electron photodetachment is observed in the wavelength range corresponding to base absorption (260-270 nm). This demonstrates the feasibility of gas-phase UV spectroscopy on large DNA anions. The calculations and the wavelength dependence suggest that the electron photodetachment is initiated at the bases and not at the phosphates. This also indicates that, although direct photodetachment could also occur, autodetachment from excited states, presumably corresponding to base excitation, is the dominant process at 260 nm. Excited-state dynamics of large DNA strands still remains largely unexplored, and photo-oxidation studies on trapped DNA multiply charged anions can help in bridging the gap between gas-phase studies on isolated bases or base pairs and solution-phase studies on full DNA strands.
Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS
Researchers
http://hdl.handle.net/2268/382
10.1021/ja068440z

File(s) associated to this reference

Fulltext file(s):

FileCommentaryVersionSizeAccess
Restricted access
2007-JACS-photodetachmentDNA.pdfPublisher postprint310.25 kBRequest copy
Restricted access
Manuscript_ja068440z_revised.pdfAuthor preprint469.55 kBRequest copy

Additional material(s):

File Commentary Size Access
Restricted access
Article ja068440z SI revised.pdfSupporting information1.86 MBRequest copy

Bookmark and Share SFX Query

All documents in ORBi are protected by a user license.