Metal-Triggered DNA Folding by Different Mechanisms |
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Authors: | Wei Deng Bin Zheng Wei Ding Hong Zhu Hao-jun Liang |
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Institution: | 1.Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026, China2.School of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China3.Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026, China;CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei 230026, China |
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Abstract: | Metal-mediated base pairs by the interaction between metal ions and artificial bases in oligonucleotides has been widely used in DNA nanotechnology and biosensing technique. Using isothermal titration calorimetry, circular dichroism spectroscopy and fluorescence spectroscopy, the folding process of T-C-rich oligonucleotides (TCO) induced by Hg2+ and Ag+ with the synthetic sequence d(T6C6T6C6T6C6T6) was studied and analyzed. Although thermodynamic data predict that TCO should initially fold into a relatively stable hairpin through two possible pathways of conformational transitions whether Hg2+ or Ag+ were added at first, the mechanisms and final products between the two are entirely different from isothermal titration calorimetry outcomes. When Hg2+ were added first, the haipin was formed through T-Hg-T structure with further stabilization by C-Ag-C after Ag+ addition. However, it is proposed that an unusual metal-base pair for Ag+ binding is generated instead classical C-Ag-C when Ag+ was injected first. Moreover, further confirmation of this unconventional metal-base pair T-Ag-C was verified by circular dichroism and fluorescence spectroscopy. |
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Keywords: | Metal-mediated base pairs Hg2+ and Ag+ T-C-rich oligonucleotides Folding mechanisms T-Ag-C base pair |
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