Method of Measuring Oligonucleotide-Metal Affinities: Interactions of the Thrombin Binding Aptamer with K+ and Sr2+
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- 作者：J. Micah Wilcox ; Don L. Rempel ; Michael L. Gross
- 刊名：Analytical Chemistry
- 出版年：2008
- 出版时间：April 1, 2008
- 年：2008
- 卷：80
- 期：7
- 页码：2365 - 2371
- 全文大小：139K
- 年卷期：v.80,no.7(April 1, 2008)
- ISSN：1520-6882
文摘
We report a new, mass spectrometry-based method formeasuring affinity constants for specific metal ion bindingto DNA, particularly for quadruplex DNA. This method,which is applicable to other systems, utilizes the gas-phasesignal fractions, as determined by mass spectrometry,from the bound and unbound species as input into amathematical model that determines various parameters,one of which is the binding affinity constant. The systemused to develop and test the model was the thrombin-binding aptamer, an appropriate quadruplex structurethat binds both K+ and Sr2+ cations. Using this method,we measured the binding constants of potassium andstrontium cations with the quadruplex structure to be5000 and 240 nM, respectively. We then applied themethod to measure the change in enthalpy of the bindingof strontium cations to the thrombin binding aptamer. The
H for this interaction is -71 kJ/mol (-17 kcal/mol).The binding constant measurements are consistent withearlier measurements on the same system, and themeasured change in enthalpy is in excellent agreementwith previous work.
H for this interaction is -71 kJ/mol (-17 kcal/mol).The binding constant measurements are consistent withearlier measurements on the same system, and themeasured change in enthalpy is in excellent agreementwith previous work.