Comparison of potassium ion preference of potassium-sensing oligonucleotides, PSO-1 and PSO-2, carrying the human and Oxytricha telomeric sequence, respectively
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Human [G3(TTAG3)3] and Oxytricha [G4(T4G4)3] telomere model oligonucleotides, PSO-1 and PSO-2, bearing two fluorophores, 6-carboxyfluorescein (6-FAM) and 6-carboxytetramethylrhodamine (6-TAMRA) at their 5′- and 3′-termini, respectively, were synthesized. Both of them can form an intramolecular antiparallel tetraplex upon addition of K+, and an enhanced fluorescence resonance energy transfer (FRET) was observed. PSO-1 showed a 43,000 times higher selectivity for K+ against Na+. Fluorometric and circular dichroism spectrophotometric studies revealed that this system is useful for the evaluation of the interaction of different telomeric repeat oligonucleotide sequences with metal ions.
KeywordsFluorescence resonance energy transfer (FRET) G-quartet Potassium-sensing oligonucleotide (PSO) Telomere Tetraplex
The authors are grateful to Prof Hiroki Kondo of the Kyushu Institute of Technology for helpful discussions. This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan. The authors are also grateful for the financial support from the Japan Society for the Promotion of Science.
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