Sodium-ion binding to DNA: Detection by ultrafast time-resolved stokes-shift spectroscopy

被引:31
作者
Gearheart, LA
Somoza, MM
Rivers, WE
Murphy, CJ [1 ]
Coleman, RS
Berg, MA
机构
[1] Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA
[2] Ohio State Univ, Dept Chem, Columbus, OH 43210 USA
关键词
D O I
10.1021/ja0363617
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The nature of the counterion is shown to have a pronounced effect on the apparent dynamic polarity in the interior of DNA. Time-resolved Stokes-shift measurements in the 80 ps to 40 ns time range were made on a polarity-sensitive fluorophore (coumarin 102) that replaces a base pair in an oligonucleotide. With sodium counterions, the emission spectrum narrows with time, whereas with tetrabutylammonium counterions, it does not. Our interpretation is that a subpopulation of helices have sodium cations bound in a fashion that slows the normal dynamics. Copyright © 2003 American Chemical Society.
引用
收藏
页码:11812 / 11813
页数:2
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