Charge separation and charge delocalization identified in long-living states of photoexcited DNA

• DOI: 10.1073/pnas.1323700111
• Publication Date: 2014-03-11T01:34:20Z
• Authors: Dominik B. Bucher; Bert M. Pilles; Thomas Carell; Wolfgang Zinth
• Keywords: Radical ion; Nucleobase

Significance The high photostability of single nucleobases is related to the rapid disposal UV excitation energy from high-lying electronic states into heat, preventing damaging reactions. However, in biological important DNA strands, further long-living excited are found. With femtosecond vibrational spectroscopy, these now identified as charge-separated states, which delocalized along strand. charge separation directed by redox potential involved bases and thus encoded sequence. presence charged species strands for a considerably long time after light absorption may lead reactions—oxidative or reductive damage—currently not considered photochemistry.