Binding of $TMPyP^{3+}$ porphyrin to poly(A)-poly(U) polynucleotide: a spectroscopic study
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| Formato: | Preprint |
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2024
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| author | Ryazanova, Olga A. Voloshin, Igor M. Dubey, Igor Ya. Dubey, Larysa V. Karachevtsev, Victor A. |
| author_facet | Ryazanova, Olga A. Voloshin, Igor M. Dubey, Igor Ya. Dubey, Larysa V. Karachevtsev, Victor A. |
| contents | The porphyrins are macrocyclic compounds widely used as photosensitizers in anticancer photodynamic therapy. The binding of a tricationic meso-tris(N-methylpyridinium)-porphyrin, $TMPyP^{3+}$, to poly(A)-poly(U) polynucleotide has been studied in neutral buffered solution, pH6.9, of low and near-physiological ionic strength in a wide range of molar phosphate-to-dye ratios (P/D). Effective $TMPyP^{3+}$ binding to the biopolymer was established using absorption spectroscopy, polarized fluorescence, fluorimetric titration and resonance light scattering. We propose a model in which $TMPyP^{3+}$ binds to the polynucleotide in two competitive binding modes: at low P/D ratios (< 4) external binding of the porphyrin to polynucleotide backbone without self-stacking dominates, and at higher P/D (> 30) the partially stacked porphyrin J-dimers are embedded into the polymer groove. Enhancement of the porphyrin emission was observed upon binding in all P/D range, contrasting the binding of this porphyrin to poly(G)-poly(C) with significant quenching of the porphyrin fluorescence at low P/D ratios. This observation indicates that $TMPyP^{3+}$ can discriminate between poly(A)-poly(U) and poly(G)-poly(C) polynucleotides at low P/D ratios. Formation of highly scattering extended porphyrin aggregates was observed near the stoichiometric in charge binding ratio, P/D = 3. It was revealed that the efficiency of the porphyrin external binding and aggregation is reduced in the solution of near-physiological ionic strength. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2404_12245 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Binding of $TMPyP^{3+}$ porphyrin to poly(A)-poly(U) polynucleotide: a spectroscopic study Ryazanova, Olga A. Voloshin, Igor M. Dubey, Igor Ya. Dubey, Larysa V. Karachevtsev, Victor A. Biological Physics The porphyrins are macrocyclic compounds widely used as photosensitizers in anticancer photodynamic therapy. The binding of a tricationic meso-tris(N-methylpyridinium)-porphyrin, $TMPyP^{3+}$, to poly(A)-poly(U) polynucleotide has been studied in neutral buffered solution, pH6.9, of low and near-physiological ionic strength in a wide range of molar phosphate-to-dye ratios (P/D). Effective $TMPyP^{3+}$ binding to the biopolymer was established using absorption spectroscopy, polarized fluorescence, fluorimetric titration and resonance light scattering. We propose a model in which $TMPyP^{3+}$ binds to the polynucleotide in two competitive binding modes: at low P/D ratios (< 4) external binding of the porphyrin to polynucleotide backbone without self-stacking dominates, and at higher P/D (> 30) the partially stacked porphyrin J-dimers are embedded into the polymer groove. Enhancement of the porphyrin emission was observed upon binding in all P/D range, contrasting the binding of this porphyrin to poly(G)-poly(C) with significant quenching of the porphyrin fluorescence at low P/D ratios. This observation indicates that $TMPyP^{3+}$ can discriminate between poly(A)-poly(U) and poly(G)-poly(C) polynucleotides at low P/D ratios. Formation of highly scattering extended porphyrin aggregates was observed near the stoichiometric in charge binding ratio, P/D = 3. It was revealed that the efficiency of the porphyrin external binding and aggregation is reduced in the solution of near-physiological ionic strength. |
| title | Binding of $TMPyP^{3+}$ porphyrin to poly(A)-poly(U) polynucleotide: a spectroscopic study |
| topic | Biological Physics |
| url | https://arxiv.org/abs/2404.12245 |