TY - JOUR
T1 - Ultrafast dynamics in DNA
T2 - "Fraying" at the end of the helix
AU - Andreatta, Daniele
AU - Sen, Sobhan
AU - Pérez Lustres, J. Luis
AU - Kovalenko, Sergey A.
AU - Ernsting, Nikolaus P.
AU - Murphy, Catherine J.
AU - Coleman, Robert S.
AU - Berg, Mark A.
PY - 2006/5/31
Y1 - 2006/5/31
N2 - The dynamics of the electric fields in the interior of DNA are measured by using oligonucleotides in which a native base pair is replaced by a dye molecule (coumarin 102) whose emission spectrum is sensitive to the local electric field. Time resolved measurements of the emission pectrum have been extended to a six decade time range (40 fs to 40 ns) by combining results from time-correlated photon counting, flourescence up-conversion, the transient absorption. Recent results showed that when the reporter is placed in the center of the oligonucleotide, the dynamics are very broadly distributed over this entire time range and do not show specific time constants associated with individual processes (Andreatta D.; et al. J. Am Chem. Soc. 2005, 127, 7270). This paper examines an oligonucleotide with the reporter near its end. The broadly distributed relaxation seen before remains with little attenuation. In addition, a new relaxation with a well-defined relaxation time of 5 ps appears. This process is assigned to the rapid component of "fraying" at the end of the helix.
AB - The dynamics of the electric fields in the interior of DNA are measured by using oligonucleotides in which a native base pair is replaced by a dye molecule (coumarin 102) whose emission spectrum is sensitive to the local electric field. Time resolved measurements of the emission pectrum have been extended to a six decade time range (40 fs to 40 ns) by combining results from time-correlated photon counting, flourescence up-conversion, the transient absorption. Recent results showed that when the reporter is placed in the center of the oligonucleotide, the dynamics are very broadly distributed over this entire time range and do not show specific time constants associated with individual processes (Andreatta D.; et al. J. Am Chem. Soc. 2005, 127, 7270). This paper examines an oligonucleotide with the reporter near its end. The broadly distributed relaxation seen before remains with little attenuation. In addition, a new relaxation with a well-defined relaxation time of 5 ps appears. This process is assigned to the rapid component of "fraying" at the end of the helix.
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U2 - 10.1021/ja0582105
DO - 10.1021/ja0582105
M3 - Article
C2 - 16719468
AN - SCOPUS:33744832602
SN - 0002-7863
VL - 128
SP - 6885
EP - 6892
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 21
ER -