Binding of Metallated Porphyrin-Imidazophenazine Conjugate to Tetramolecular Quadruplex Formed by Poly(G): a Spectroscopic Investigation
- 174 Downloads
The binding of telomerase inhibitor ZnTMPyP3+–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 ZnTMPyP3+ 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.
KeywordsPorphyrin–imidazophenazine conjugate Poly(G) G-quadruplex Absorption Fluorescence
Compliance with Ethical Standards
The authors declare that our manuscript complies with the all Ethical Rules applicable for this journal and that there are no conflicts of interests.
- 12.Dolphin D (ed) (1978) The porphyrins. Academic Press, New YorkGoogle Scholar
- 24.Ishikawa Y, Yamashita A, Uno T (2001) Chem Pharm Bull 49(3):287–293Google Scholar
- 31.Maraval A, Franco S, Vialas C, Pratviel G, Blasco MA, Meunier B (2003) Org Biomol Chem 1(6):921–927Google Scholar
- 33.Dubey LV, Ilchenko MM, Zozulya VN, Ryazanova OA, Pogrebnoy PV, Dubey IY (2011) Int Rev Biophys Chem 2(4):147–152Google Scholar
- 37.Zozulya VN, Ryazanova OA, Voloshin IM, Dubey LV, Dubey IY (2011) Int Rev Biophys Chem 2(4):112–119Google Scholar
- 41.Dubey I, Pratviel G, Meunier B (1998) Compt Rend Acad Sci (Paris), Ser IIC 1(4):259–267Google Scholar
- 42.Dubey L, Ryazanova O, Zozulya V, Fedoryak D, Dubey I (2011) Nucleosides Nucleotides Nucleic Acids 30(7–8):585–596Google Scholar
- 50.Ryazanova OA, Voloshin IM, Dubey IY, Dubey LV, Zozulya VN (2008) Ann N Y Acad Sci 1130:293–299Google Scholar