Organometallic photonucleases: A novel class of DNA-cleaving agents

The first demonstration of DNA cleavage by an organic radical generated via homolysis of a metalalkyl bond in a Cp-metal complex is presented. Irradiation of CpW(CO)3CH3 (1.5 molecules/base pair) produced methyl radical, giving single-strand cleavage of pBR322 DNA. This process was inhibited by the general radical trap cysteine and by TEMPO, which traps carbon radicals but not oxygen-centered radicals.