Splitting of cis-syn cyclobutane thymine-thymine dimers by radiolysis and its relevance to enzymatic photoreactivation.
The 137Cs-gamma-irradiation of cis-syn thymine-thymine cyclobutane type dimers has been studied in aqueous solution. The mechanism of thymine dimer cleavage by eaq-, CO2.-, OH.,SO4.-,Br2.- and isopropanol radicals was studied using high pressure liquid chromatography (HPLC). Evidence that the one-electron reductants studied induce dimer cleavage partially by a chain reaction is presented. Approximate values for the one-electron reduction potential of thymine-thymine are obtained and thermodynamic calculations are presented in order to predict the direction of electron transfer in the case of enzymatic photoreactivation.
Faculty of Science, Health and Medical Studies, North East Wales Institute, Deeside, Clwyd, UK.
P F
PF
Heelis
D J
DJ
Deeble
S T
ST
Kim
A
A
Sancar
D002588:Cesium Radioisotopes; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000502:physiology*; D005720:Gamma Rays; D011740:Pyrimidine Dimers / Q000528:radiation effects*; D012996:Solutions; D014867:Water
D002588:Cesium Radioisotopes; D011740:Pyrimidine Dimers; D012996:Solutions; D014867:Water; D004255:Deoxyribodipyrimidine Photo-Lyase