1. Laboratoire “Lésions des Acides Nucléiques”, INAC/SCIB—UMR-E n°3 CEA-UJF, CEA Grenoble, 17 rue des Martyrs, F-38 054 Grenoble cedex 9, France, and School of Science and Technology, and Örebro Life Science Center, Örebro University, 701 82 Örebro, Sweden