Monitoring the direct and indirect damage of DNA bases and polynucleotides by using time-resolved infrared spectroscopy.
The nucleotide 5'-dGMP and polynucleotide poly(dGdC).poly(dGdC) have been irradiated by using a 200-fs, 200-nm laser pulses and spectrally characterized by using time-resolved infrared spectroscopy. Under the experimental conditions, 200-nm excitation generates both electronic excited states and radical cations through photoionization; the former decay rapidly to vibrationally hot ground state. By using infrared signatures we have been able to follow these processes, and at time scales of >1 ns we observe an infrared marker band at 1,702 cm(-1) within both 5'-dGMP and the polynucleotide assigned to a photoionized product of guanine. This transient has also been reproduced through indirect chemistry through the reaction with photogenerated carbonate radical with 5'-dGMP. The ability to use time-resolved infrared spectroscopy in this way paves the way for developing solution-phase studies to investigate both direct and indirect radiation chemistry of DNA.
Kuimova
Marina K
MK
School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
Cowan
Alexander J
AJ
Matousek
Pavel
P
Parker
Anthony W
AW
Sun
Xue Zhong
XZ
Towrie
Michael
M
George
Michael W
MW
D004247:DNA / Q000737:chemistry* / Q000528:radiation effects*; D004249:DNA Damage; D007834:Lasers; D011089:Polydeoxyribonucleotides / Q000737:chemistry / Q000528:radiation effects; D017550:Spectroscopy, Fourier Transform Infrared
D011089:Polydeoxyribonucleotides; C016681:poly(dG).poly(dC); D004247:DNA