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Vol 42(2008) N 4 p. 616-622; D.N. Kaluzhny, Ph.S. Bondarev, A.K. Shchyolkina, M.A. Livshits, O.F. Borisova Intramolecular G-quadruplexes formed by d(GT)12 microsatellite sequence in the presence of K+ Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, RussiaReceived - 2007-12-14; Accepted - 2008-02-20 Polymorphic d(GT)n microsatellite sequences are known to dramatically affect the regulation of gene expression. CD spectroscopy, UV melting, fluorescence polarization of ethidium bromide (EtBr), and FRET allowed the detection of a new G-quartet fold formed by the d(GT)12 oligonucleotide in 0.01 M Na-phosphate (pH 8.0) in the presence of 0.1 M KCl. The monomolecular type of the structure was verified by measuring the rotational relaxation time (ρ = 28 ± 0.5 ns) of the EtBr: d(GT)12complex. CD spectra supported the G-quartet formation. FRET was used to estimate the distance between intercalated EtBr and FITC covalently attached to the 5' end of d(GT)12 (R ≤ 17 Å). The experimental data agree with the self-folding of d(GT)12 in a G-quartet structure. G-quadruplex, d(GT)n microsatellite repeats, CD, UV melting, FRET, ethidium bromide fluorescence |
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