Thymine Dimerization in DNA Is an Ultrafast Photoreaction

• DOI: 10.1126/science.1135428
• Publication Date: 2007-02-03T07:58:48Z
• Authors: Wolfgang J. Schreier; Tobias E. Schrader; Florian O. Koller; Peter Gilch; Carlos E. Crespo-...; Vijay N. Swaminathan; Thomas Carell; Wolfgang Zinth; Bern Kohler
• Keywords: Pyrimidine dimer; Thymine; Picosecond; Ultraviolet; Quantum yield; Ultraviolet light

Femtosecond time-resolved infrared spectroscopy was used to study the formation of cyclobutane dimers in all-thymine oligodeoxynucleotide (dT) 18 by ultraviolet light at 272 nanometers. The appearance marker bands spectra indicates that are fully formed ∼1 picosecond after excitation. ultrafast this mutagenic photolesion points an excited-state reaction is approximately barrierless for bases properly oriented instant absorption. low quantum yield photoreaction proposed result from infrequent conformational states unexcited polymer, revealing a strong link between conformation before absorption and photodamage.