Femtosecond dynamics of the DNA intercalator ethidium and electron transfer with mononucleotides in water

被引:86
作者
Fiebig, T [1 ]
Wan, CZ [1 ]
Kelley, SO [1 ]
Barton, JK [1 ]
Zewail, AH [1 ]
机构
[1] CALTECH, Arthur Amos Noyes Lab Chem Phys, Lab Mol Sci, Pasadena, CA 91125 USA
关键词
D O I
10.1073/pnas.96.4.1187
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Ethidium (E) is a powerful probe of DNA dynamics and DNA-mediated electron transfer (ET). Molecular dynamical processes, such as solvation and orientation, are important on the time scale of ET. Here, we report studies of the femtosecond and picosecond time-resolved dynamics of E, E with 2'deoxyguanosine triphosphate (GTP) in eater, and E with 7-deaza-2'-deoxyguanosine triphosphate (ZTP) in water; E undergoes ET with ZTP but not GTP. These studies elucidate the critical role of relative orientational motions of the donor-acceptor complex on ET processes in solution. For ET from ZTP to E, such motions are in fact the rate-determining step, Our results indicate that these complexes reorient before ET, The time scale for the solvation of E in water is 1 ps, and the orientational relaxation time of E is 70 ps, The impact of orientational and solvation effects on ET between E and mononucleotides must be considered in the application of E as a probe of DNA ET.
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页码:1187 / 1192
页数:6
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