Publication Date:
2008-10-11
Description:
The high photostability of DNA is commonly attributed to efficient radiationless electronic relaxation processes. We used femtosecond time-resolved fluorescence spectroscopy to reveal that the ensuing dynamics are strongly dependent on base sequence and are also affected by higher-order structure. Excited electronic state lifetimes in dG-doped d(A)20 single-stranded DNA and dG.dC-doped d(A)20.d(T)20 double-stranded DNA decrease sharply with the substitution of only a few bases. In duplexes containing d(AGA).d(TCT) or d(AG).d(TC) repeats, deactivation of the fluorescing states occurs on the subpicosecond time scale, but the excited-state lifetimes increase again in extended d(G) runs. The results point at more complex and molecule-specific photodynamics in native DNA than may be evident in simpler model systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schwalb, Nina K -- Temps, Friedrich -- New York, N.Y. -- Science. 2008 Oct 10;322(5899):243-5. doi: 10.1126/science.1161651.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut fur Physikalische Chemie, Christian-Albrechts-Universitat zu Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany. schwalb@phc.uni-kiel.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18845751" target="_blank"〉PubMed〈/a〉
Keywords:
Base Pairing
;
Base Sequence
;
Circular Dichroism
;
DNA/*chemistry
;
DNA, Single-Stranded/chemistry
;
Hydrogen Bonding
;
Nucleic Acid Conformation
;
Oligodeoxyribonucleotides/*chemistry
;
Photochemistry
;
Purines/chemistry
;
Pyrimidines/chemistry
;
Spectrometry, Fluorescence
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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