title: Is UV-Induced Electron-Driven Proton Transfer Active in a Chemically Modified A·T DNA Base Pair?
abstract: Transient electronic and vibrational absorption spectroscopies have been used to investigate whether UV-induced electron-driven proton transfer (EDPT) mechanisms are active in a chemically modified adenine-thymine (A·T) DNA base pair. To enhance the fraction of biologically relevant Watson-Crick (WC) hydrogen-bonding motifs and eliminate undesired Hoogsteen structures, a chemically modified derivative of A was synthesized, 8-(tert-butyl)-9-ethyladenine (8tBA). Equimolar solutions of 8tBA and silyl-protected T nucleosides in chloroform yield a mixture of WC pairs, reverse WC pairs, and residual monomers. Unlike previous transient absorption studies of WC guanine-cytosine (G·C) pairs, no clear spectroscopic or kinetic evidence was identified for the participation of EDPT in the excited-state relaxation dynamics of 8tBA·T pairs, although ultrafast (sub-100 fs) EDPT cannot be discounted. Monomer-like dynamics are proposed to dominate in 8tBA·T.
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: Katharina
authors.initials: K
authors.lastname: Röttger
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: Hugo J B
authors.initials: HJB
authors.lastname: Marroux
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: Arsène F M
authors.initials: AFM
authors.lastname: Chemin
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: Emma
authors.initials: E
authors.lastname: Elsdon
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: Thomas A A
authors.initials: TAA
authors.lastname: Oliver
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: Steven T G
authors.initials: STG
authors.lastname: Street
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Henderson
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: M Carmen
authors.identifier: 0000-0001-7307-2871
authors.initials: MC
authors.lastname: Galan
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: Andrew J
authors.identifier: 0000-0001-5551-9609
authors.initials: AJ
authors.lastname: Orr-Ewing
authors.affiliation: School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K.
authors.forename: Gareth M
authors.identifier: 0000-0002-2005-9486
authors.initials: GM
authors.lastname: Roberts
mesh_terms: D000225:Adenine / Q000737:chemistry*; D020029:Base Pairing; D004247:DNA / Q000737:chemistry*; D004583:Electrons; D011522:Protons; D011789:Quantum Theory; D013941:Thymine / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D011522:Protons; D004247:DNA; D000225:Adenine; D013941:Thymine