Sequence dependence of energy transfer in DNA oligonucleotides

被引:71
作者
Xu, DG [1 ]
Nordlund, TM [1 ]
机构
[1] Univ Alabama, Dept Phys, Birmingham, AL 35294 USA
关键词
D O I
10.1016/S0006-3495(00)76663-X
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
The sequence, temperature, concentration, and solvent dependence of singlet energy transfer from normal DNA bases to the e-aminopurine base in synthesized DNA oligomers were investigated by optical spectroscopy. Transfer was shown directly by a variable fluorescence excitation band at 260-280 nm. Adenine (A) is the most efficient energy donor by an order of magnitude. Stacks of A adjacent to 2AP act as an antenna for 2AP excitation. An interposed G, C, or T base between A and 2AP effectively blocks transfer from A to 2AP. Base stacking facilitates transfer, while base pairing reduces energy transfer slightly. The efficiency is differentially temperature dependent in single- and double-stranded oligomers and is highest below 0 degrees C in samples measured. An efficiency transition occurs well below the melting transition of a double-stranded decamer. The transfer efficiency in the duplex decamer d(CTGA[2AP]TTCAG)(2) is moderately dependent on the sample and salt concentration and is solvent dependent. Transfer at physiological temperature over more than a few bases is improbable, except along consecutive A's, indicating that singlet energy transfer is not a major factor in the localization of UV damage in DNA. These results have features in common with recently observed electron transfer from 2AP to G in oligonucleotides.
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页码:1042 / 1058
页数:17
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