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Ryazanova O, Zozulya V, Voloshin I, Dubey L, Dubey I, Karachevtsev V. Binding of Metallated Porphyrin-Imidazophenazine Conjugate to Tetramolecular Quadruplex Formed by Poly(G): a Spectroscopic Investigation. J Fluoresc 2015; 25:1897-904. [PMID: 26449960 DOI: 10.1007/s10895-015-1682-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/28/2015] [Indexed: 01/10/2023]
Abstract
The binding of telomerase inhibitor ZnTMPyP(3+)-ImPzn, Zn(II) derivative of tricationic porphyrin-imidazophenazine conjugate, to tetramolecular quadruplex structure formed by poly(G) was studied in aqueous solutions at neutral pH and near physiological ionic strength using absorption and polarized fluorescent spectroscopy techniques. Three binding modes were determined from the dependences of the fluorescence intensity and polarization degree for the porphyrin and phenazine moieties of the conjugate on molar polymer-to-dye ratio (P/D). The first one is outside electrostatic binding of positively charged porphyrin fragments to anionic phosphate groups of the polymer which prevails only at very low P/D values and manifests itself by substantial fluorescence quenching. It is suggested that the formation of externally bound porphyrin dimers occurs. The other two binding modes observed at high P/D are embedding of the ZnTMPyP(3+) moiety into the groove of poly(G) quadruplex accompanied by more than 3-fold enhancement of the conjugate emission, and simultaneous intercalation of the phenazine fragment between the guanine bases accompanied by the increase of its fluorescence polarization degree up to 0.25. Thus Zn(II) conjugate seems to be promising ligand for the stabilization of G-quadruplex structures since porphyrin binding to poly(G) is strengthened by additional intercalation of phenazine moiety.
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Affiliation(s)
- Olga Ryazanova
- Department of Molecular Biophysics, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin ave, 61103, Kharkov, Ukraine.
| | - Victor Zozulya
- Department of Molecular Biophysics, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin ave, 61103, Kharkov, Ukraine
| | - Igor Voloshin
- Department of Molecular Biophysics, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin ave, 61103, Kharkov, Ukraine
| | - Larysa Dubey
- Department of Synthetic Bioregulators, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Zabolotnogo str, 03680, Kyiv, Ukraine
| | - Igor Dubey
- Department of Synthetic Bioregulators, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, 150 Zabolotnogo str, 03680, Kyiv, Ukraine
| | - Victor Karachevtsev
- Department of Molecular Biophysics, B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin ave, 61103, Kharkov, Ukraine
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Spectroscopic Studies on Binding of Porphyrin-Phenazine Conjugate to Four-Stranded Poly(G). J Fluoresc 2015; 25:1013-21. [PMID: 26076929 DOI: 10.1007/s10895-015-1585-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/20/2015] [Indexed: 10/23/2022]
Abstract
Binding of a novel cationic porphyrin-imidazophenazine conjugate, TMPyP(3+)-ImPzn, to four-stranded poly(G) was investigated in aqueous solutions of neutral pH under near physiological ionic conditions using absorption, polarized fluorescent spectroscopy and fluorescence titration techniques. In absence of the polymer the conjugate folds into stable internal heterodimer with stacking between the porphyrin and phenazine chromophores. Binding of TMPyP(3+)-ImPzn to poly(G) is realized by two competing ways. At low polymer-to-dye ratio (P/D < 6) outside electrostatic binding of the cationic porphyrin moieties of the conjugate to anionic polynucleotide backbone with their self-stacking is predominant. It is accompanied by heterodimer dissociation and distancing of phenazine moieties from the polymer. This binding mode is characterized by strong quenching of the conjugate fluorescence. Increase of P/D results in the disintegration of the porphyrin stacks and redistribution of the bound conjugate molecules along the polymer chain. At P/D > 10 another binding mode becomes dominant, embedding of TMPyP(3+)-ImPzn heterodimers into poly(G) groove as a whole is occurred.
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Negrutska VV, Dubey LV, Ilchenko MM, Dubey IY. Design and study of telomerase inhibitors based on G-quadruplex ligands. ACTA ACUST UNITED AC 2013. [DOI: 10.7124/bc.000817] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- V. V. Negrutska
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - L. V. Dubey
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - M. M. Ilchenko
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - I. Ya. Dubey
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
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