Ak. Dotse et al., Remote cis-syn-thymine [2+2] dimers are not repaired by radical cations migrating in duplex DNA, J AM CHEM S, 122(29), 2000, pp. 6825-6833
A series of DNA oligomers was prepared containing an anthraquinone derivati
ve linked to a 5'-end, a cis-syn-[2 + 2]thymine dimer and strategically loc
ated GG steps. These compounds were designed to test the claim that one-ele
ctron oxidation of the DNA leads to repair of remote thymine dimers. Irradi
ation of the anthraquinone leads to remote damage at the 5'-G of GG steps t
hat are positioned both before and after the thymine dimer, but there is no
detectable (<3%) repair of the thymine dimer. These findings are in contra
st to a previous series of reports in which repair of the thymine dimer is
reported to occur 40 times more efficiently than reaction at GG steps when
the remote one-electron oxidation is initiated by irradiation of a covalent
ly linked Rh-containing metallointercalator.