TY - JOUR
T1 - Is UV-Induced Electron-Driven Proton Transfer Active in a Chemically Modified A•T DNA Base Pair?
AU - Roettger, Katharina
AU - Marroux, Hugo
AU - Chemin, Arsene
AU - Elsdon, Emma
AU - Oliver, Thomas A A
AU - Street, Steve
AU - Henderson, Alexander S J
AU - Galan, Carmen
AU - Orr-Ewing, Andrew
AU - Roberts, Gareth
PY - 2017/5/4
Y1 - 2017/5/4
N2 - 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-(t-butyl)-9-ethyl-adenine (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.
AB - 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-(t-butyl)-9-ethyl-adenine (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.
U2 - 10.1021/acs.jpcb.7b02679
DO - 10.1021/acs.jpcb.7b02679
M3 - Article (Academic Journal)
C2 - 28394602
SN - 1520-6106
VL - 121
SP - 4448
EP - 4455
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 17
ER -