biostudies-literature00470Unknown7(1)Yao XThe interaction of ligands with G-quadruplexes has attracted considerable attention due to its importance in molecular recognition and anticancer drugs design. Here, we utilize triplet excited state as a sensitive reporter to study the binding interaction of zinc cationic porphyrin (ZnTMPyP4) with three G-quadruplexes, AG₃(T₂AG₃)₃, (G₄T₄G₄)2, and (TG₄T)4. By monitoring the triplet decay dynamics of ZnTMPyP4 with transient absorption spectroscopy, the coexisted binding modes via π-π stacking of porphyrin macrocycle and the G-quartets are allowed to be identified quantitatively, which involve intercalation (25% and 36%) versus end-stacking (75% and 64%) for AG₃(T₂AG₃)₃ and (G₄T₄G₄)2, and end-stacking (23%) versus partial intercalation (77%) for (TG₄T)4. It is shown that the steric hindrance of the axial water decreases greatly the percentage of intercalation. Further, a rapid assessment of binding stoichiometry is fulfilled by measuring the triplet decay dynamics under various [G-quadruplex]/[ZnTMPyP4] ratios. The binding stoichiometric ratios of G-quadruplex/ZnTMPyP4 are 1:2 for AG₃(T₂AG₃)₃, 1:1 for (G₄T₄G₄)2, and 1:2 for (TG₄T)4, which agree well with results obtained by the conventional method of continuous variation analysis. These results reveal a clear scenario of G-quadruplex/ZnTMPyP4 interaction and provide mechanistic insights for the application of anticancer drug designs using G-quadruplex as target.Scientific reports10951https://www.ebi.ac.uk/biostudies/studies/S-EPMC5591184biostudies-literatureInteraction between G-Quadruplex and Zinc Cationic Porphyrin: The Role of the Axial Water.PMC5591184Li XLiu KSong DYao XQin TYu ZYang CSu H47falseInteraction between G-Quadruplex and Zinc Cationic Porphyrin: The Role of the Axial Water.The interaction of ligands with G-quadruplexes has attracted considerable attention due to its importance in molecular recognition and anticancer drugs design. Here, we utilize triplet excited state as a sensitive reporter to study the binding interaction of zinc cationic porphyrin (ZnTMPyP4) with three G-quadruplexes, AG₃(T₂AG₃)₃, (G₄T₄G₄)2, and (TG₄T)4. By monitoring the triplet decay dynamics of ZnTMPyP4 with transient absorption spectroscopy, the coexisted binding modes via π-π stacking of porphyrin macrocycle and the G-quartets are allowed to be identified quantitatively, which involve intercalation (25% and 36%) versus end-stacking (75% and 64%) for AG₃(T₂AG₃)₃ and (G₄T₄G₄)2, and end-stacking (23%) versus partial intercalation (77%) for (TG₄T)4. It is shown that the steric hindrance of the axial water decreases greatly the percentage of intercalation. Further, a rapid assessment of binding stoichiometry is fulfilled by measuring the triplet decay dynamics under various [G-quadruplex]/[ZnTMPyP4] ratios. The binding stoichiometric ratios of G-quadruplex/ZnTMPyP4 are 1:2 for AG₃(T₂AG₃)₃, 1:1 for (G₄T₄G₄)2, and 1:2 for (TG₄T)4, which agree well with results obtained by the conventional method of continuous variation analysis. These results reveal a clear scenario of G-quadruplex/ZnTMPyP4 interaction and provide mechanistic insights for the application of anticancer drug designs using G-quadruplex as target.2017-01-01T00:00:00Z2017 Sep2024-11-08T21:17:16.849Z2019-03-27T02:55:54ZS-EPMC55911842888749710.1038/s41598-017-11413-8