title: Base-specific ionization of deprotonated nucleotides by resonance enhanced two-photon detachment.
abstract: The intrinsic ionization energy of a base in DNA plays a critical role in determining the energies at which damage mechanisms may emerge. Here, a two-photon resonance-enhanced ionization scheme is presented that utilizes the (1)ππ* transition, localized on the DNA base, to elucidate the base-specific ionization in a deprotonated nucleotide. In contrast to previous reports, the scheme is insensitive to competing ionization channels arising from the sugar-phosphate backbone. Using this approach, we demonstrate that for all bases except guanine, the lowest electron detachment energy corresponds to detachment from the sugar-phosphate backbone and allows us to determine the lowest adiabatic ionization energy for the other three bases for the first time in an isolated nucleotide.
authors: Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors: Adam S
authors: AS
authors: Chatterley
authors: Ashley S
authors: AS
authors: Johns
authors: Vasilios G
authors: VG
authors: Stavros
authors: Jan R R
authors: JR
authors: Verlet
mesh_terms: D000225:Adenine / Q000737:chemistry*; D003596:Cytosine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D004249:DNA Damage; D004583:Electrons; D006147:Guanine / Q000737:chemistry*; D008958:Models, Molecular; D017785:Photons; D011522:Protons; D013816:Thermodynamics; D013941:Thymine / Q000737:chemistry*
chemical_list: D011522:Protons; D006147:Guanine; D003596:Cytosine; D004247:DNA; D000225:Adenine; D013941:Thymine