Mechanism of UV‐Induced Formation of Dewar Lesions in DNA

Abstract

The importance of a backbone: The mechanism of formation of Dewar lesions has been investigated by using femtosecond IR spectroscopy and ab initio calculations of the exited state. The 4π electrocyclization is rather slow, occurs with an unusual high quantum yield, and--surprisingly--is controlled by the phosphate backbone.

Identification of charge separated states in thymine single strands

“…TRIR has been shown to allow the unequivocal spectral identification of electronically excited states, reaction intermediates and photoproducts. 8,13,[19][20][21] The obtained data show that UV excitation in (dT) 18 leads to the formation of electronically excited states that decay to the electronic ground state on a 100 ps time scale. Comparison of the spectral signature with experimentally determined anionic and cationic thymine species provides unequivocal evidence that the observed species resemble charge separated states between two thymine bases.…”

Plastic antibody for DNA damage: fluorescent imaging of BPDE–dG adducts in genomic DNA

“…The combination of 1 (G-]) and 3 (calix [6]arene-]) exhibits the highest selectivity against the DNA adduct probes (Fig. 2c).…”

“…The total yields were 31.1% for the monoallylated p-tertbutylcalix [4]arene (2), 17.5% for the allylated p-tert-butylcalix [6]arene (3) and 11.2% for the allylated p-tert-butylcalix [8]arene (4), respectively. For the allylated p-tert-butylcalix [6]arene (3), 1 …”

“…[1][2][3] Screening of DNA damage, together with the identication of permanent alterations in DNA, has promoted a new burgeoning eld in the early diagnosis of cancer. [4][5][6] It is an arduous task to specically detect trace DNA damage in the presence of a large excess of unmodied nucleotides (0.1-100 adducts per 10 8 nts) with a minute amount of DNA available. [7][8][9] High-affinity natural antibodies have been produced for the detection of DNA damage.…”

Ultrafast spectroscopy of UV-induced DNA-lesions — on the search for strategies which keep DNA alive

“…For this reaction a favourable arrangement of the adjacent thymine molecules is a prerequisite and variations of the arrangement influence the quantum efficiency [4,6]. The secondary photoreaction from the T(6-4)T lesion to the Dewar isomer occurs on the 100 ps time scale [7]. By the combination of different experimental techniques and theoretical simulations we obtain deep insight into the excited state dynamics of Dewar formation.…”