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Yuan F, Liu X, Li J, Tan L. Interactions of arene ruthenium(II) complexes [η 6-(C 6H 6)Ru(pprip)Cl] + and [η 6-(C 6H 6)Ru(H 2iiP)Cl] + with RNA triplex poly(U)•poly(A)*poly(U). J Biol Inorg Chem 2023; 28:559-570. [PMID: 37477757 DOI: 10.1007/s00775-023-02008-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/30/2023] [Indexed: 07/22/2023]
Abstract
Two arene ruthenium(II) complexes [η6-(C6H6)Ru(pprip)Cl]PF6 (Ru1; pprip = 2-(3-phenyl-1H-pyrazol-4-yl)-imidazolo[4,5-f][1,10]phenanthroline) and [η6-(C6H6)Ru(H2iiP)Cl]PF6 (Ru2; H2iiP = 2-(indole-3-yl)-imidazolo[4,5-f][1,10]phenanthroline) have been synthesized and characterized in this work. Binding properties of Ru1 and Ru2 with the triplex RNA poly(U)•poly(A)*poly(U) were investigated by spectrophotometry and spectrofluorometry as well as viscosimetry. Analysis of spectroscopic titrations and viscosity measurements show that the two complexes bind with the triplex through intercalation, while the binding affinity for Ru2 toward the triplex is stronger than that for Ru1. Melting experiments indicate that the stabilizing effects of Ru1 and Ru2 toward the triplex differ from each other. Under the conditions used herein, Ru1 only stabilizes the Hoogsteen base-paired strand (third strand) without affecting stabilization of the Watson-Crick base-paired strand (the template duplex) of the triplex, while Ru2 stabilizes both the template duplex and the third strand. Although the two complexes prefer to stabilizing the third strand rather than the template duplex, the third-strand stabilization effect of Ru2 is stronger than that of Ru1. The obtained results of this work reveal that the planarity of the intercalative ligands plays an important role in the triplex stabilization by arene Ru(II) complexes.
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Affiliation(s)
- Feng Yuan
- College of Chemistry, Xiangtan University, Xiangtan, 411105, People's Republic of China
| | - Xiaohua Liu
- Academic Affairs Office, Xiangtan University, Xiangtan, 411105, People's Republic of China
| | - Juan Li
- Key Lab of Environment-Friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan, 411105, People's Republic of China.
| | - Lifeng Tan
- Key Lab of Environment-Friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan, 411105, People's Republic of China.
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2
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Peng X, Liu X, Tan L. Interaction of ruthenium(Ⅱ) polypyridyl complexes [Ru(phen)2(L)]2+ (L = PIP, p-HPIP and m-HPIP) with RNA poly(A)•poly(U): each complex unexpectedly exhibiting a destabilizing effect on RNA. Bioorg Chem 2023; 135:106523. [PMID: 37027949 DOI: 10.1016/j.bioorg.2023.106523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023]
Abstract
To further explore the binding properties of Ru(Ⅱ) polypyridine complexes with RNA, three Ru(Ⅱ) complexes [Ru(phen)2(PIP)]2+ (Ru1), [Ru(phen)2(p-HPIP)]2+ (Ru2), and [Ru(phen)2(m- HPIP)]2+ (Ru3) have been synthesized and characterized in this work. The binding properties of three Ru(Ⅱ) complexes with RNA duplex poly(A)•poly(U) have been investigated by spectral and viscosity experiments. These studies all support that these three Ru(Ⅱ) complexes bind to poly RNA duplex poly(A)•poly(U) by intercalation, and Ru1 without substituents has a stronger binding affinity for poly(A)•poly(U). Interestingly, the thermal melting experiments show that these three Ru(Ⅱ) complexes all destabilize RNA duplex poly(A)•poly(U), and the destabilizing effect can be explained by the conformational changes of duplex structure induced by intercalating agents. To the best of our knowledge, this work report for the first time a small molecule capable of destabilizing an RNA duplex, which reflects that the substitution effect of intercalated ligands has an important influence on the affinity of Ru(Ⅱ) complexes to RNA duplex, and that not all Ru(Ⅱ) complexes show thermal stability effects on an RNA duplex.
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Affiliation(s)
- Xing Peng
- College of Chemistry, Xiangtan University, Xiangtan 411105, Peoples Republic of China
| | - Xiaohua Liu
- Academic Affairs Office, Xiangtan University, Xiangtan 411105, Peoples Republic of China
| | - Lifeng Tan
- Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, XiangtanUniversity, Xiangtan 411105, Peoples Republic of China; Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Xiangtan University, Xiangtan 411105, Peoples Republic of China.
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3
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Binacchi F, Elia C, Cirri D, Van de Griend C, Zhou XQ, Messori L, Bonnet S, Pratesi A, Biver T. A biophysical study of the interactions of palladium(II), platinum(II) and gold(III) complexes of aminopyridyl-2,2'-bipyridine ligands with RNAs and other nucleic acid structures. Dalton Trans 2023; 52:598-608. [PMID: 36562298 DOI: 10.1039/d2dt03483b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Metal compounds form an attractive class of ligands for a variety of nucleic acids. Five metal complexes bearing aminopyridyl-2,2'-bipyridine tetradentate ligands and possessing a quasi-planar geometry were challenged toward different types of nucleic acid molecules including RNA polynucleotides in the duplex or triplex form, an RNA Holliday four-way junction, natural double helix DNA and a DNA G-quadruplex. The binding process was monitored comparatively using different spectroscopic and melting methods. The binding preferences that emerge from our analysis are discussed in relation to the structural features of the metal complexes.
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Affiliation(s)
- Francesca Binacchi
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, 56124 Pisa, Italy.
| | - Cassandra Elia
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, 56124 Pisa, Italy.
| | - Damiano Cirri
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, 56124 Pisa, Italy.
| | - Corjan Van de Griend
- Leiden Institute of Chemistry, Leiden University, 2333CC Leiden, The Netherlands
| | - Xue-Quan Zhou
- Leiden Institute of Chemistry, Leiden University, 2333CC Leiden, The Netherlands
| | - Luigi Messori
- Laboratory of Metals in Medicine (MetMed), Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - Sylvestre Bonnet
- Leiden Institute of Chemistry, Leiden University, 2333CC Leiden, The Netherlands
| | - Alessandro Pratesi
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, 56124 Pisa, Italy.
| | - Tarita Biver
- University of Pisa, Department of Chemistry and Industrial Chemistry, Via G. Moruzzi 13, 56124 Pisa, Italy.
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4
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Macii F, Cupellini L, Stifano M, Santolaya J, Pérez-Arnaiz C, Pucci A, Barone G, García B, Busto N, Biver T. Combined spectroscopic and theoretical analysis of the binding of a water-soluble perylene diimide to DNA/RNA polynucleotides and G-quadruplexes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 260:119914. [PMID: 34015745 DOI: 10.1016/j.saa.2021.119914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/23/2021] [Accepted: 05/02/2021] [Indexed: 06/12/2023]
Abstract
We present here a combined spectroscopic and theoretical analysis of the binding of N,N'-bis(2-(1-piperazino)ethyl)-3,4,9,10-perylenetetracarboxylic acid diimide dichloride (PZPERY) to different biosubstrates. Absorbance titrations and circular dichroism experiments, melting studies and isothermal calorimetry (ITC) titrations reveal a picture where the binding to natural double-stranded DNA is very different from that to double and triple-stranded RNAs (poly(A)∙poly(U) and poly(U)∙poly(A)⁎poly(U)). As confirmed also by the structural and energetic details clarified by density functional theory (DFT) calculations, intercalation occurs for DNA, with a process driven by the combination of aggregates disruption and monomers intercalation. Oppositely, for RNAs, no intercalation but groove binding with the formation of supramolecular aggregates is observed. Among all the tested biosubstrates, the affinity of PZPERY towards DNA G-quadruplexes (G4) is the greatest one with a preference for human telomeric G4s. Focusing on hybrid G4 forms, either sitting-atop ("tetrad-parallel") or lateral ("groove-parallel") binding modes were considered in the discussion of the experimental results and molecular dynamics (MD) simulations. Both turned out to be possible concurrently, in agreement also with the experimental binding stoichiometries higher than 2:1.
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Affiliation(s)
- Francesca Macii
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy
| | - Lorenzo Cupellini
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy
| | - Mariassunta Stifano
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy
| | - Javier Santolaya
- Department of Chemistry, University of Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain
| | - Cristina Pérez-Arnaiz
- Department of Chemistry, University of Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain
| | - Andrea Pucci
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy
| | - Giampaolo Barone
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Viale delle Scienze Ed. 17, 90128 Palermo, Italy
| | - Begoña García
- Department of Chemistry, University of Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain
| | - Natalia Busto
- Department of Chemistry, University of Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain.
| | - Tarita Biver
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy; Department of Pharmacy, University of Pisa, Via Bonanno Pisano 6, 56126 Pisa, Italy.
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Substituent effects on the interactions of ruthenium(II) polypyridyl complexes [Ru(bpy)2(6-R-dppz)]2+ (R = hydroxy and fluorine) with the RNA triplex poly(rU)·poly(rA) × poly(rU). Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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6
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On the Different Mode of Action of Au(I)/Ag(I)-NHC Bis-Anthracenyl Complexes Towards Selected Target Biomolecules. Molecules 2020; 25:molecules25225446. [PMID: 33233711 PMCID: PMC7699860 DOI: 10.3390/molecules25225446] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 12/20/2022] Open
Abstract
Gold and silver N-heterocyclic carbenes (NHCs) are emerging for therapeutic applications. Multiple techniques are here used to unveil the mechanistic details of the binding to different biosubstrates of bis(1-(anthracen-9-ylmethyl)-3-ethylimidazol-2-ylidene) silver chloride [Ag(EIA)2]Cl and bis(1-(anthracen-9-ylmethyl)-3-ethylimidazol-2-ylidene) gold chloride [Au(EIA)2]Cl. As the biosubstrates, we tested natural double-stranded DNA, synthetic RNA polynucleotides (single-poly(A), double-poly(A)poly(U) and triple-stranded poly(A)2poly(U)), DNA G-quadruplex structures (G4s), and bovine serum albumin (BSA) protein. Absorbance and fluorescence titrations, mass spectrometry together with melting and viscometry tests show significant differences in the binding features between silver and gold compounds. [Au(EIA)2]Cl covalently binds BSA. It is here evidenced that the selectivity is high: low affinity and external binding for all polynucleotides and G4s are found. Conversely, in the case of [Ag(EIA)2]Cl, the binding to BSA is weak and relies on electrostatic interactions. [Ag(EIA)2]Cl strongly/selectively interacts only with double strands by a mechanism where intercalation plays the major role, but groove binding is also operative. The absence of an interaction with triplexes indicates the major role played by the geometrical constraints to drive the binding mode.
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7
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Comparative studies on the binding interaction of two chiral Ru(II) polypyridyl complexes with triple- and double-helical forms of RNA. J Inorg Biochem 2020; 214:111301. [PMID: 33166867 DOI: 10.1016/j.jinorgbio.2020.111301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/12/2020] [Accepted: 10/25/2020] [Indexed: 12/27/2022]
Abstract
Two chiral Ru(II) polypyridyl complexes, Δ-[Ru(bpy)2(6-F-dppz)]2+ (Δ-1; bpy = 2,2'-bipyridine, 6-F-dppz = 6-fluorodipyrido[3,2-a:2',3'-c]phenazine) and Λ-[Ru(bpy)2(6-F-dppz)]2+ (Λ-1), have been synthesized and characterized as binders for the RNA poly(U)•poly(A)*poly(U) triplex and poly(A)•poly(U) duplex in this work. Analysis of the UV-Vis absorption spectra and fluorescence emission spectra indicates that the binding of intercalating Δ-1 with the triplex and duplex RNA is greater than that of Λ-1, while the binding affinities of the two enantiomers to triplex structure is stronger than that of duplex structure. Fluorescence titrations show that the two enantiomers can act as molecular "light switches" for triple- and double-helical RNA. Thermal denaturation studies revealed that that the two enantiomers are more stable to Watson-Crick base-paired double strand of the triplex than the Hoogsteen base-paired third strand, but their stability and selectivity are different. For Δ-enantiomer, the increase of the thermal stability of the Watson-Crick base-paired duplex (13 °C) is slightly stronger than of the Hoogsteen base-paired strand (10 °C), displaying no obvious selectivity. However, compared to the Hoogsteen base-paired strand (5 °C), the stability of the Λ-enantiomer to the Watson-Crick base-paired duplex (13 °C) is more significant, which has obvious selectivity. The overall increase in viscosity of the RNA-(Λ-1) system and its curve shape are similar to that of the RNA-(Δ-1) system, suggesting that the binding modes of two enantiomers with RNA are intercalation. The obtained results in this work may be useful for understanding the binding differences in chiral Ru(II) polypyridyl complexes toward RNA triplex and duplex.
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8
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Macii F, Perez-Arnaiz C, Arrico L, Busto N, Garcia B, Biver T. Alcian blue pyridine variant interaction with DNA and RNA polynucleotides and G-quadruplexes: changes in the binding features for different biosubstrates. J Inorg Biochem 2020; 212:111199. [DOI: 10.1016/j.jinorgbio.2020.111199] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/21/2020] [Accepted: 07/21/2020] [Indexed: 12/19/2022]
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9
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Dong Z, Liu X, Tan L. Biophysical insights into the interaction of two enantiomers of Ru(II) complex [Ru(bpy) 2(7-CH 3-dppz)] 2+ with the RNA poly(U-A⁎U) triplex. J Biol Inorg Chem 2020; 25:1085-1095. [PMID: 33040210 DOI: 10.1007/s00775-020-01825-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 09/28/2020] [Indexed: 01/14/2023]
Abstract
To determine the factors affecting the stabilization of RNA triple-stranded structure by chiral Ru(II) polypyridyl complexes, a new pair of enantiomers, ∆-[Ru(bpy)2(7-CH3-dppz)]2+ (∆-1; bpy = 2,2'-bipyridine, 7-CH3-dppz = 7-methyl-dipyrido[3,2-a,2',3'-c]phenazine) and Λ-[Ru(bpy)2(7-CH3-dppz)]2+ (Λ-1), have been synthesized and characterized in this work. Binding properties of the two enantiomers with the RNA poly(U-A⁎U) triplex (where "-" denotes the Watson - Crick base pairing and "⁎" denotes the Hoogsteen base pairing) have been studied by spectroscopy and hydrodynamics methods. Under the conditions used in this study, changes in absorption spectra of the two enantiomers are not very different from each other when bound to the triplex, although the binding affinity of ∆-1 is higher than that of Λ-1. Fluorescence titrations and viscosity experiments give convincing evidence for a true intercalative binding of enantiomers with the triplex. However, melting experiments indicated that the two enantiomers selectively stabilized the triplex. The enantiomer ∆-1 stabilize the template duplex and third-strand of the triplex, while it's more effective for stabilization of the template duplex. In stark contrast to ∆-1, Λ-1 stabilizes the triplex without any effect on the third-strand stabilization, suggesting this one extremely prefers to stabilize the template duplex rather than third-strand. Besides, the triplex stabilization effect of ∆-1 is more marked in comparison with that of Λ-1. The obtained results suggest that substituent effects and chiralities of Ru(II) polypyridyl complexes play important roles in the triplex stabilization. Complexes Λ/Δ-[Ru(bpy)2(7-CH3-dppz)]2+ (Λ/Δ-1; bpy = 2,2'-bipyridine, 7-CH3-dppz = 7-methyl-dipyrido[3,2-a,2',3'-c]phenazine) were prepared as stabilizers for poly(U-A ∗ U) triplex. Results suggest the triplex stabilization depends the chiral structures of Λ/Δ-1, indicating that [Ru(bpy)2(7-CH3-dppz)]2+ is a non-specific intercalator for poly(U-A ∗ U) investigated in this work.
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Affiliation(s)
- Zhan Dong
- College of Chemistry, Xiangtan University, Xiangtan, 411105, People's Republic of China
| | - Xiaohua Liu
- Academic Affairs Office, Xiangtan University, Xiangtan, 411105, People's Republic of China
| | - Lifeng Tan
- Key Lab of Environment-Friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan, 411105, People's Republic of China. .,Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Xiangtan University, Xiangtan, 411105, People's Republic of China.
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10
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Tan L, Zhang J. A phenolic hydroxyl in the ortho- and meta-positions on the main ligands effect on the interactions of [Ru(phen) 2(o-HPIP)] 2+ and [Ru(phen) 2(m-HPIP)] 2+ with the poly(U)·poly(A)*poly(U) triplex. J Inorg Biochem 2020; 213:111268. [PMID: 33065523 DOI: 10.1016/j.jinorgbio.2020.111268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/23/2020] [Accepted: 09/27/2020] [Indexed: 01/14/2023]
Abstract
The association of two ruthenium(II) complexes [Ru(phen)2(o-HPIP)]2+ (Ru1; phen = 1,10-phenanthroline, o-HPIP = 2-(2-hydroxyphenyl)-imidazo[4,5-f][1,10] phenanthroline) and [Ru(phen)2(m-HPIP)]2+ (Ru2; m-HPIP = 2-(3-hydroxyphenyl)-imidazo[4,5-f][1,10]phenan- throline) with the RNA poly(U)·poly(A)⁎poly(U) triplex has been investigated by spectrophotometric titrations and melting experiments in this work. All experimental data reveal an intercalative triplex-binding mode of the two complexes, whereas the binding constant for Ru1 is significantly higher than that for Ru2. Circular dichroism spectroscopic investigations show that the two complexes could bind to the chiral environment of the triplex, but the triplex perturbation effects induced by Ru1 are more marked. Thermal denaturation experiments demonstrate that both Ru1 and Ru2 display a large binding preference and stabilizing effect for the third strand over the Watson-Crick base-paired duplex of the triplex. However, the third-strand stabilizing effect of Ru1 is much more effective than that of Ru2. The obtained results suggest that positions of the phenolic group on the main ligands have significant effect on the binding of the two complexes with poly(U)·poly(A)⁎poly(U) triplex.
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Affiliation(s)
- Lifeng Tan
- College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China; Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, People's Republic of China.
| | - Jingwen Zhang
- College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China
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Jiang L, Liu X, Tan L. Synthesis and characterization of chiral Ru(II) polypyridyl complexes and their binding and stabilizing effects toward triple-helical RNA. J Inorg Biochem 2020; 213:111263. [PMID: 33011626 DOI: 10.1016/j.jinorgbio.2020.111263] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/10/2020] [Accepted: 09/21/2020] [Indexed: 01/11/2023]
Abstract
Two novel chiral Ru(II) complexes, Λ- and Δ-[Ru(bpy)2(7-CF3-dppz)]2+ (Λ-1 and Δ-1; bpy = 2,2'-bipyridine, 7-CF3-dppz = 7-trifluoromethyl-dipyrido[3,2-a:2',3'-c]phenazine), were synthesized and characterized in this work. The binding and stabilizing effects of Λ-1 and Δ-1 toward the RNA poly(U)•poly(A)*poly(U) triplex were studied by various biophysical techniques. Absorption spectra and fluorescence quenching indicates that the binding affinity of Δ-1 is slightly higher than that Λ-1. Both enantiomers induce significant positive viscosity changes that are indicative of intercalative binding, whereas changes in the relative viscosities of the triplex are found to be more pronounced with Δ-1. Melting experiments indicate that the triplex stabilization effects of both enantiomers are significantly different from each other. With Λ-1, the stabilization of the Watson-Crick base-paired duplex (the template duplex) of the triplex shows a moderate increase, whereas the stabilization of the Hoogsteen base-paired strand (third-strand) exhibits slight decrease under the same conditions, suggesting Λ-1 prefers to stabilize the template duplex rather than third-strand. In stark contrast to Λ-1, Δ-1 can not only strongly stabilize the template duplex, but also moderately increase the third-strand stabilization, even so, which imply that Δ-1 also prefer to stabilize the template duplex instead of the third-strand. These suggest that the [Ru(bpy)2(7-CF3-dppz)]2+ is similar as a non-specific metallointercalator the triplex studied in this work. Combined with our recent research, the obtained results further indicate that Δ- enantiomers rather than Λ-ones of Ru(II) polypyridyl complexes usually exhibit stronger binding and stabilizing effects toward the triplex.
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Affiliation(s)
- Lijuan Jiang
- College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Xiaohua Liu
- Academic Affairs Office, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Lifeng Tan
- Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, People's Republic of China; Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Xiangtan University, Xiangtan 411105, People's Republic of China.
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12
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Ivanov M, Sizov V, Kudrev A. Thermal unwinding of Polyadenylic·Polyuridylic acid complex with TMPyP4 porphyrin in aqueous solutions. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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13
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Ma C, Chen M, He H, Chen L. Detection of coralyne and heparin by polymerase extension reaction using SYBR Green I. Mol Cell Probes 2019; 46:101423. [PMID: 31323319 DOI: 10.1016/j.mcp.2019.101423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 07/14/2019] [Accepted: 07/16/2019] [Indexed: 11/24/2022]
Abstract
Polydeoxyadenosine (poly (dA)) has been extensively applied for detecting many drug molecules. Herein, we developed a sensitive method for detecting coralyne and heparin using a modified DNA probe with poly (dA) at one end. In the absence of coralyne, the DNA probe was digested by the Exonuclease I (Exo I), and therefore the SYBR Green I (SG I) emitted an extremely low fluorescent signal. While coralyne specifically binding to poly (dA) with strong propensity could remarkably restrain the disintegration of the DNA probe, through which as a template the second strand of DNA sequence was formed with the introduction of DNA polymerase. Therefore, the fluorescent signal of SG I was intensified to quantify coralyne. Based on this method, heparin can be determined due to its strong affinity towards coralyne. This method showed a linear range from 2 to 500 nM for coralyne with a low detection limit of 0.98 nM, and the linear range of heparin was from 1 to 100 nM when 1.25 nm was the detection limit. The proposed method was also implemented successfully in biological samples and showed a potential application for screening potential therapeutic molecules.
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Affiliation(s)
- Changbei Ma
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing, 102488, China; School of Life Sciences, Central South University, Changsha, 410013, China.
| | - Miangjian Chen
- School of Life Sciences, Central South University, Changsha, 410013, China
| | - Hailun He
- School of Life Sciences, Central South University, Changsha, 410013, China
| | - Leilei Chen
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing, 102488, China.
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Wang F, Sun Y, Liu X, Li Y, Tan L. Third-strand stabilizing effects of the RNA poly(U)·poly(A)*poly(U) triplex by a ruthenium(II) polypyridine complex and its hexaarginine peptide conjugate. Int J Biol Macromol 2019; 135:1134-1141. [PMID: 31176864 DOI: 10.1016/j.ijbiomac.2019.06.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/28/2019] [Accepted: 06/04/2019] [Indexed: 01/14/2023]
Abstract
In this work, a Ru(II) complex [Ru(bpy)2(pip-CO2H)]2+ (Ru1) and its hexaarginine peptide conjugate [Ru(bpy)2(pic-Arg6)]8+ (Ru2) have been synthesized and characterized. The binding of Ru1 and Ru2 with poly(U)•poly(A)*poly(U) triplex has been studied. Results suggest that Ru1 binds in the surface of the minor groove while Ru2 binds to the minor groove of the triplex. Consequently, the triplex stabilization is barely affected by Ru1, while with Ru2 the triplex stabilizing effect is so strong that that dissociation of the triplex shows an overlapping of both melting processes with the melting temperature increased to a maximum of 56.1 °C at the CRu2/CUAU ratio of 0.05, where ΔTm1 and ΔTm2 are 19.6 and 10.1 °C, respectively. Furthermore, the effect of Ru2 stabilizing the third strand at such a low binding ratio of 0.05 is more marked than what obsereved for flavone luteolin and [Ru(bpy)2(mdpz)]2+, which are so far the strongest triplex stabilizers in the reported organic small molecules and metal complexes, respectively. Considering the structure natures of Ru2, conceivably except for electrostatic interaction, the forces stabilizing the triplex should also involve hydrophobic interaction and hydrogen bingding. To our knowledge, this work represents a first example of improving the triplex stabilization by a metallopeptide.
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Affiliation(s)
- Fangfang Wang
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Yanmei Sun
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Xiaohua Liu
- Academic Affairs Office, Xiangtan University, Xiangtan 411105, PR China
| | - Yi Li
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, PR China
| | - Lifeng Tan
- Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, PR China; Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Xiangtan University, Xiangtan 411105, PR China.
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15
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Wang F, Ma S, Feng Y, Liu X, Tan L. Binding propterties of two Ru(II) polypyridyl complexes containing dppz units and fluorine groups with poly(U)·poly(A) ∗ poly(U) triplex. J Inorg Biochem 2019; 197:110705. [PMID: 31071642 DOI: 10.1016/j.jinorgbio.2019.110705] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/26/2019] [Accepted: 05/01/2019] [Indexed: 01/14/2023]
Abstract
In this work, two Ru(II)-dppz (dppz = dipyrido[3,2-a:2',3'-c]phenazine) complexes containing fluorine substituents, [Ru(bpy)2(7-F-dppz)]2+ (Ru1, bpy = 2,2'-bipyridine, 7-F-dppz = 7-fluorodipyrido[3,2-a:2',3'-c]phenazine) and [Ru(phen)2(7-F-dppz)]2+ (Ru2, phen = 1,10-phenanthroline), have been synthesized and characterized. Binding properties of Ru1 and Ru2 with the RNA poly(U)·poly(A) ∗ poly(U) triplex have been studied by spectroscopic methods and viscosity measurements. The obtained results indicate that the binding differences of the two complexes with the triplex may be attributed to the ancillary ligand effects, implying that the better planarity and greater hydrophobicity of ancillary ligands are advantageous to the π-π stacking interaction between Ru2 and the triplex, thus Ru2 stabilizes the triplex strongly than Ru1. Denaturation of the triplex shows that both Ru1 and Ru2 can not only highly stabilize the template duplex of the triplex, but also significantly stabilize the third strand. Compared with the triplex stabilizing effects for the reported Ru(II)-dppz complexes, thermal melting experiments suggest that the fluorine substituent on the ligand dppz can probably decrease electrostatic repulsion between the three strands of the triplex, thereby Ru1 and Ru2 significantly increase the triplex stabilization. Results obtained from this work further confirm that the substituent electron effect of dppz-based ligands and the planarity and hydrophobicity of ancillary ligands play an important role in the triplex stabilizing effects by Ru(II)-dppz complexes.
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Affiliation(s)
- Fangfang Wang
- College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Shuai Ma
- College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Yongdeng Feng
- College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Xiaohua Liu
- School of Chemical Engineering, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Lifeng Tan
- Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, People's Republic of China; Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Xiangtan University, Xiangtan 411105, People's Republic of China.
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16
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Feng Y, Liu X, Ma S, Wang F, Tan L. Ruthenium(II) polypyridyl complex [Ru(phen) 2dppz-idzo] 2+ as a colorimetric molecular "light switch" and powerful stabilizer for the RNA triplex poly(U)·poly(A)*poly(U). SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 212:240-245. [PMID: 30641364 DOI: 10.1016/j.saa.2018.12.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/09/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
The interaction of [Ru(phen)2dppz-idzo]2+ (phen = 1,10-phenanthroline, dppz-idzo = dppz-imidazolone) with triplex RNA poly(U)·poly(A)*poly(U) was carried out by using spectroscopic and viscometric techniques in this work. Luminescent titrations suggest that [Ru(phen)2dppz-idzo]2+ shows better selectivity for poly(U)·poly(A)*poly(U) compared with poly(U)·poly(A) and poly(U), this complex exhibits a "light switch" effect with an emission enhancement factor of about 123 in the presence of poly(U)·poly(A)*poly(U). Significantly, this "light switch" behavior could even be observed by the naked eye under irradiation with UV light. To our knowledge, [Ru(bpy)2dppz-idzo]2+ is the first small molecule able to serve as a colorimetric molecular "light switch" for the triplex poly(U)·poly(A)*poly(U). Combined with the spectral and viscometric results as well as [Ru(phen)2dppz-idzo]2+ stabilizing the template duplex poly(U)·poly(A), we speculate that [Ru(phen)2dppz-idzo]2+ prefers to bind with the Hoogsteen base-paired strand (the third strand) of the triplex, thus the intercalating [Ru(phen)2dppz-idzo]2+ stabilizing the third strand is more marked in comparison with the Watson-Crick base-paired duplex of the triplex. The results obtained here may be useful for understanding the interaction of triplex RNA poly(U)·poly(A)*poly(U) with small molecule, particularly ruthenium(II) complexes.
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Affiliation(s)
- Yongdeng Feng
- College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Xiaohua Liu
- School of Chemical Engineering, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Shuai Ma
- College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Fangfang Wang
- College of Chemistry, Xiangtan University, Xiangtan 411105, People's Republic of China
| | - Lifeng Tan
- Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, People's Republic of China.
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17
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Ma S, Wang F, Feng Y, Liu X, Tan L. Binding properties of ruthenium(II) complexes [Ru(phen)2(dicnq)]2+ and [Ru(bpy)2(dicnq)]2+ with the RNA triplex poly(U)·poly(A)*poly(U). Polyhedron 2019. [DOI: 10.1016/j.poly.2019.01.062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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18
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Zarudnaya MI, Kolomiets IM, Potyahaylo AL, Hovorun DM. Structural transitions in poly(A), poly(C), poly(U), and poly(G) and their possible biological roles. J Biomol Struct Dyn 2018; 37:2837-2866. [PMID: 30052138 DOI: 10.1080/07391102.2018.1503972] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The homopolynucleotide (homo-oligonucleotide) tracts function as regulatory elements at various stages of mRNAs life cycle. Numerous cellular proteins specifically bind to these tracts. Among them are the different poly(A)-binding proteins, poly(C)-binding proteins, multifunctional fragile X mental retardation protein which binds specifically both to poly(G) and poly(U) and others. Molecular mechanisms of regulation of gene expression mediated by homopolynucleotide tracts in RNAs are not fully understood and the structural diversity of these tracts can contribute substantially to this regulation. This review summarizes current knowledge on different forms of homoribopolynucleotides, in particular, neutral and acidic forms of poly(A) and poly(C), and also biological relevance of homoribopolynucleotide (homoribo-oligonucleotide) tracts is discussed. Under physiological conditions, the acidic forms of poly(A) and poly(C) can be induced by proton transfer from acidic amino acids of proteins to adenine and cytosine bases. Finally, we present potential mechanisms for the regulation of some biological processes through the formation of intramolecular poly(A) duplexes.
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Affiliation(s)
- Margarita I Zarudnaya
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine
| | - Iryna M Kolomiets
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine
| | - Andriy L Potyahaylo
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine
| | - Dmytro M Hovorun
- a Department of Molecular and Quantum Biophysics , Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , Kyiv , Ukraine.,b Department of Molecular Biotechnology and Bioinformatics , Institute of High Technologies, Taras Shevchenko National University of Kyiv , Kyiv , Ukraine
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Peng M, Ni W, Tan L. Effects of the fluorine substituent positions of the intercalating ligands on the binding behavior and third-strand stabilization of two Ru(II) complexes toward poly(U)•poly(A)*poly(U) triplex RNA. J Inorg Biochem 2017; 175:276-283. [PMID: 28806644 DOI: 10.1016/j.jinorgbio.2017.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/10/2017] [Accepted: 08/05/2017] [Indexed: 01/03/2023]
Abstract
Two new Ru(II) polypyridyl complexes containing fluorine substituents, [Ru(bpy)2(o-fpip)]2+ (Ru1, bpy=2,2'-bipyridine, o-fpip=2-(2-fluorophenyl)imidazo[4,5-f] [1,10]phenanthroline) and [Ru(bpy)2(p-fpip)]2+ (Ru2, p-fpip=2-(4-fluorophenyl)imidazo[4,5-f] [1,10]phenanthroline) have been synthesized as binders for poly(U)•poly(A)∗poly(U) triplex RNA. The binding of the two complexes with the triplex RNA has been investigated by spectroscopic methods and viscosity measurements. Analysis of the electronic absorption spectra indicates that the association of intercalating Ru2 with the triplex RNA is greater than that of Ru1, which is also supported by spectroscopic titrations and viscosity measurements. Thermal denaturation studies reflect that third-strand stabilization depend on the nature of the two complexes and Ru2 is more effective for stabilization of the triplex RNA. Circular dichroism spectra of the triplex RNA in the presence of metal complexes indicate that the binding-induced CD perturbation of the triplex structure is more obvious by Ru2. The main results obtained here suggest that the positions of fluorine substituent in the intercalating ligands have a significant effect on the two complexes stabilizing the third strand.
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Affiliation(s)
- Mengna Peng
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Wen Ni
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Lifeng Tan
- Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, PR China.
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20
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Tang W, Zhu Z, Tan L. [Ru(bpy)2(7-CH3-dppz)](2+) and [Ru(phen)2(7-CH3-dppz)](2+) as metallointercalators that affect third-strand stabilization of the poly(U)˙poly(A)*poly(U) triplex. MOLECULAR BIOSYSTEMS 2017; 12:1478-85. [PMID: 26999574 DOI: 10.1039/c6mb00094k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Stable RNA triplexes play key roles in many biological processes. However, due to Hoogsteen base pairing, triplexes are thermodynamically less stable than the corresponding duplexes. To understand the factors effecting the stabilization of RNA triplexes by octahedral ruthenium(ii) complexes, two Ru(ii) complexes, [Ru(bpy)2(7-CH3-dppz)](2+) (Ru) and [Ru(phen)2(7-CH3-dppz)](2+) (Ru), have been synthesized and characterized in this work. The interactions of the two Ru(ii) complexes with the poly(U)˙poly(A)*poly(U) triplex are investigated by spectrophotometry, spectrofluorometry, circular dichroism as well as viscometry. The results demonstrate that the two complexes are able to enhance the stability of the RNA triplex and serve as molecular "light switches" for the triplex. However, Ru and Ru affecting the stabilization of the third strand are significantly weaker than that of the Watson-Crick base-paired duplex, suggesting that the binding of the two complexes with the triplex is favored by the Watson-Crick base-paired duplex to a large extent. In addition, considering the nature of Ru and Ru, we presume that their binding differences may be due to different ancillary ligand effects. This study further advances our knowledge on the interaction of RNA triple-stranded structures with metal complexes, particularly with Ru(ii) complexes.
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Affiliation(s)
- Wuzhi Tang
- College of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China.
| | - Zhiyuan Zhu
- College of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China.
| | - Lifeng Tan
- College of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China. and Key Lab of Environmentally Friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, P. R. China
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21
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Zhu Z, Peng M, Zhang J, Tan L. Interaction of octahedral ruthenium(II) polypyridyl complex [Ru(bpy) 2(PIP)] 2+ with poly(U)·poly(A)*poly(U) triplex: Increasing third-strand stabilization of the triplex without affecting the stability of the duplex. J Inorg Biochem 2017; 169:44-49. [PMID: 28104569 DOI: 10.1016/j.jinorgbio.2017.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/22/2016] [Accepted: 01/03/2017] [Indexed: 01/10/2023]
Abstract
Triple-helical RNA are of interest because of possible biological roles as well as the potential therapeutic uses of these structures, while the stability of triplexes is usually weaker than that of the Watson-Crick base pairing duplex strand due to the electrostatic repulsion between three polyanionic strands. Therefore, how to increase the stability of the specific sequences of triplexes are of importance. In this paper the binding of a Ru(II) complex, [Ru(bpy)2(PIP)]2+ (bpy=2.2'-bipyridine, PIP=2-phenyl-1H-imidazo[4,5-f]- [1,10]-phenanthroline), with poly(U)·poly(A)*poly(U) triplex has been investigated by spectrophotometry, spectrofluorometry, viscosimetry and circular dichroism. The results suggest that [Ru(bpy)2(PIP)]2+ as a metallointercalator can stabilize poly(U)·poly(A)*poly(U) triplex (where · denotes the Watson-Crick base pairing and * denotes the Hoogsteen base pairing),while it stabilizes third-strand with no obvious effect on the duplex of poly(U)·poly(A), reflecting the binding of this complex with the triplex is favored by the Hoogsteen paired poly(U) third strand to a great extent.
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Affiliation(s)
- Zhiyuan Zhu
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Mengna Peng
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Jingwen Zhang
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Lifeng Tan
- Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, PR China.
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22
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Li J, Sun Y, Zhu Z, Zhao H, Tan L. Binding properties of ruthenium(II) complexes [Ru(bpy)2(ppn)](2+) and [Ru(phen)2(ppn)](2+) with triplex RNA: As molecular "light switches" and stabilizers for poly(U)·poly(A)*poly(U) triplex. J Inorg Biochem 2016; 161:128-33. [PMID: 27287059 DOI: 10.1016/j.jinorgbio.2016.04.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/12/2016] [Accepted: 04/18/2016] [Indexed: 01/03/2023]
Abstract
Stable RNA triplexes play key roles in many biological processes, while triplexes are thermodynamically less stable than the corresponding duplexes due to the Hoogsteen base pairing. To understand the factors affecting the stabilization of RNA triplexes by octahedral ruthenium(II) complexes, the binding of [Ru(bpy)2(ppn)](2+) (1, bpy=2,2'-bipyridine, ppn=2,4-diaminopyrimido[5,6-b]dipyrido[2,3-f:2',3'-h]quinoxaline) and [Ru(phen)2(ppn)](2+) (2, phen=1,10-phenanthroline) to poly(U)·poly(A)*poly(U) (· denotes the Watson-Crick base pairing and * denotes the Hoogsteen base pairing) has been investigated. The main results obtained here suggest that complexes 1 and 2 can serve as molecular "light switches" and stabilizers for poly(U)·poly(A)*poly(U), while the effectiveness of complex 2 are more marked, suggesting that the hydrophobicity of ancillary ligands has a significant effect on the two Ru(II) complexes binding to poly(U)·poly(A)*poly(U). This study further advances our knowledge on the binding of RNA triplexes with metal complexes, particularly with octahedral ruthenium polypyridyl complexes.
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Affiliation(s)
- Jia Li
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Yanmei Sun
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Zhiyuan Zhu
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Hong Zhao
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China
| | - Lifeng Tan
- College of Chemistry, Xiangtan University, Xiangtan 411105, PR China; Key Lab of Environmentally Friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan 411105, PR China.
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23
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Rubio AR, Busto N, Leal JM, García B. Doxorubicin binds to duplex RNA with higher affinity than ctDNA and favours the isothermal denaturation of triplex RNA. RSC Adv 2016. [DOI: 10.1039/c6ra21387a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The higher affinity of DOX with AU to give the intercalated complex AU/DOX is responsible for the disproportionation of the groove binding complex, UAU/DOX, to give rise to the AU/DOX and the U/DOX complexes at 25 °C
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Affiliation(s)
- Ana R. Rubio
- Chemistry Department
- University of Burgos
- 09001 Burgos
- Spain
| | - Natalia Busto
- Chemistry Department
- University of Burgos
- 09001 Burgos
- Spain
| | - José M. Leal
- Chemistry Department
- University of Burgos
- 09001 Burgos
- Spain
| | - Begoña García
- Chemistry Department
- University of Burgos
- 09001 Burgos
- Spain
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24
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Zhang H, Liu X, He X, Liu Y, Tan L. Experimental and density functional theory (DFT) studies on the interactions of Ru(II) polypyridyl complexes with the RAN triplex poly(U)˙poly(A)*poly(U). Metallomics 2015; 6:2148-56. [PMID: 25313017 DOI: 10.1039/c4mt00175c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
There is renewed interest in investigating triple helices because these novel structures have been implicated as a possible means of controlling cellular processes by endogenous or exogenous mechanisms. Due to the Hoogsteen base pairing, triple helices are, however, thermodynamically less stable than the corresponding duplexes. The poor stability of triple helices limits their practical applications under physiological conditions. In contrast to DNA triple helices, small molecules stabilizing RNA triple helices at present are less well established. Furthermore, most of these studies are limited to organic compounds and, to a far lesser extent, to metal complexes. In this work, two Ru(II) complexes, [Ru(bpy)2(btip)](2+) (Ru1) and [Ru(phen)2(btip)](2+) (Ru2), have been synthesized and characterized. The binding properties of the two metal complexes with the triple RNA poly(U)˙poly(A)*poly(U) were studied by various biophysical and density functional theory methods. The main results obtained here suggest that the slight binding difference in Ru1 and Ru2 may be attributed to the planarity of the intercalative ligand and the LUMO level of Ru(II) complexes. This study further advances our knowledge on the triplex RNA-binding by metal complexes, particularly Ru(II) complexes.
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Affiliation(s)
- Hong Zhang
- College of Chemistry, Xiangtan University, Xiangtan 411105, China
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25
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He X, Li J, Zhang H, Tan L. Effect of a Ru(II) polypyridyl complex [Ru(bpy)2(mdpz)]2+ on the stabilization of the RNA triplex poly(U)·poly(A)*poly(U). MOLECULAR BIOSYSTEMS 2015; 10:2552-7. [PMID: 25010433 DOI: 10.1039/c4mb00304g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
There is renewed interest in investigating triplex nucleic acids because triplexes may be implicated in a range of cellular functions. However, the stabilization of triplex nucleic acids is essential to achieve their biological functions. In contrast to triplex DNA, little has been reported concerning the recognition of triplex RNA by transition-metal complexes at present. We report here a ruthenium(ii) polypyridyl complex, [Ru(bpy)2(mdpz)](2+) (bpy = 2,2'-bipyridine; mdpz = 7,7'-methylenedioxyphenyl-dipyrido-[3,2-a:2',3'-c]phenazine), as a sensitive luminescent probe for poly(U)·poly(A)*poly(U), which can strongly stabilize the triplex RNA from 37.5 to 53.1 °C in solution. The main results further advance our knowledge on the triplex RNA-binding by metal complexes, particularly ruthenium(ii) complexes.
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Affiliation(s)
- Xiaojun He
- College of Chemistry, Xiangtan University, Xiangtan 411105, China
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26
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Mg(II) and Ni(II) induce aggregation of poly(rA)poly(rU) to either tetra-aggregate or triplex depending on the metal ion concentration. J Inorg Biochem 2015; 151:115-22. [PMID: 26004214 DOI: 10.1016/j.jinorgbio.2015.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 04/28/2015] [Accepted: 05/02/2015] [Indexed: 11/21/2022]
Abstract
The ability of magnesium(II) and nickel(II) to induce dramatic conformational changes in the synthetic RNA poly(rA)poly(rU) has been investigated. Kinetic experiments, spectrofluorometric titrations, melting experiments and DSC measurements contribute in shedding light on a complex behaviour where the action of metal ions (Na(+), Mg(2+), Ni(2+)), in synergism with other operators as the intercalating dye coralyne and temperature, all concur in stabilising a peculiar RNA form. Mg(2+) and Ni(2+) (M) bind rapidly and almost quantitatively to the duplex (AU) to give a RNA/metal ion complex (AUM). Then, by the union of two AUM units, an unstable tetra-aggregate (UAUA(M2)*) is formed which, in the presence of a relatively modest excess of metal, evolves to the UAUM triplex by releasing a single AM strand. On the other hand, under conditions of high metal content, the UAUA(M2)* intermediate rearranges to give a more stable tetra-aggregate (UAUA(M2)). As concerns the role of coralyne (D), it is found that D strongly interacts with UAUA(M2). Also, in the presence of coralyne, the ability of divalent ions to promote the transition of AUD into UAUD is enhanced, according to the efficiency sequence [Ni(2+)]≫[Mg(2+)]≫[Na(+)].
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27
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Busto N, Cano B, Tejido R, Biver T, Leal JM, Venturini M, Secco F, García B. Aggregation features and fluorescence of Hoechst 33258. J Phys Chem B 2015; 119:4575-81. [PMID: 25759973 DOI: 10.1021/jp512306c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The functionality of the bisbenzimide Hoechst 33258 in solution has been largely exploited in the quantification of DNA. Understanding of its behavior is essential to promote its widespread application and learning of biological processes. A detailed study of the dimerization process of the fluorescent blue dye Hoechst 33258 is carried out by isothermal titration calorimetry, absorbance, fluorescence, differential scanning calorimetry and T-jump kinetic measurements. The dimer/monomer ratio depends on the dye concentration and the ionic strength. The dimerization constant determined under physiological conditions (pH = 7.0; I = 0.10 M), KD = 3 × 10(4) M(-1), conveys that only micromolar concentrations of the dye can ensure reasonably high amounts of the monomer species in solution. For instance, for 10 μM dye content, the dimer prevails for I > 0.08 M, whereas the monomer is observed at low ionic strength, a key issue to be elucidated as long as the dimer species is more fluorescent than the monomer and the fluorescence intensity strongly relies on the ionic strength and the dye concentration.
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Affiliation(s)
- Natalia Busto
- †Departamento de Química, Universidad de Burgos, 09001 Burgos, Spain
| | - Beatriz Cano
- †Departamento de Química, Universidad de Burgos, 09001 Burgos, Spain
| | - Rocío Tejido
- †Departamento de Química, Universidad de Burgos, 09001 Burgos, Spain
| | - Tarita Biver
- ‡Dipartimento di Chimica e Chimica Industriale, Università di Pisa, 56126 Pisa, Italy
| | - José M Leal
- †Departamento de Química, Universidad de Burgos, 09001 Burgos, Spain
| | - Marcella Venturini
- ‡Dipartimento di Chimica e Chimica Industriale, Università di Pisa, 56126 Pisa, Italy
| | - Fernando Secco
- ‡Dipartimento di Chimica e Chimica Industriale, Università di Pisa, 56126 Pisa, Italy
| | - Begoña García
- †Departamento de Química, Universidad de Burgos, 09001 Burgos, Spain
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Li J, Sun Y, Xie L, He X, Tan L. Effect of ancillary ligands on the interaction of ruthenium(II) complexes with the triplex RNA poly(U)·poly(A)*poly(U). J Inorg Biochem 2014; 143:56-63. [PMID: 25528478 DOI: 10.1016/j.jinorgbio.2014.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 12/03/2014] [Accepted: 12/03/2014] [Indexed: 01/01/2023]
Abstract
Two new Ru(II) complexes with 1,8-naphthalimide group, [Ru(phen)2(pnip)](2+) (Ru1; phen=1,10-phenanthroline, pnip=2-[N-(p-phenyl)-1,8-napthalimide]imidazo[4',5'-f][1,10]phenanthroline) and [Ru(bpy)2(pnip)](2+) (Ru2; bpy=2,2'-bipyridine), have been synthesized and characterized. The interactions of Ru1 and Ru2 with the triplex RNA poly(U)•poly(A)*poly(U) (where • denotes the Watson-Crick base pairing and * denotes the Hoogsteen base pairing) were studied by various biophysical. Electronic spectra established that the binding affinity for Ru1 was greater than that for Ru2. Fluorescence and viscosity studies gave convincing evidence for a true intercalative binding of both complexes with the RNA triplex. UV melting studies confirmed that the two complexes could stabilize the triplex, whereas the effects of the two complexes on the stability of the Hoogsteen base-paired strand ploy(U) and the Watson-Crick base-paired duplex poly(U)•poly(A) of the triplex were different. In the case of Ru1, the increase of the thermal stability of the Hoogsteen base-paired strand was stronger than that of the Watson-Crick base-paired duplex. However, an opposite effect was observed in the case of Ru2. Circular dichroic studies suggested that the RNA triplex undergoes a conformational transition in the presence of Ru1, whereas the helicity of the RNA triplex still remains A-type in the presence of Ru2. The main results obtained here further advance our knowledge on the interaction of RNA triple-stranded structures with metal complexes, particularly ruthenium(II) complexes.
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Affiliation(s)
- Jia Li
- College of Chemistry, Xiangtan University, Xiangtan, PR China
| | - Yanmei Sun
- College of Chemistry, Xiangtan University, Xiangtan, PR China
| | - Lingjun Xie
- College of Chemistry, Xiangtan University, Xiangtan, PR China
| | - Xiaojun He
- College of Chemistry, Xiangtan University, Xiangtan, PR China
| | - Lifeng Tan
- Key Lab of Environment-friendly Chemistry and Application in Ministry of Education, Xiangtan University, Xiangtan, PR China.
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He XJ, Tan LF. Interactions of octahedral ruthenium(II) polypyridyl complexes with the RNA triplex poly(U)•poly(A)*poly(U) effect on the third-strand stabilization. Inorg Chem 2014; 53:11152-9. [PMID: 25272364 DOI: 10.1021/ic5017565] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Stable triplexes play key roles in many biological processes. Due to the Hoogsteen base pairing, triplexes are, however, thermodynamically less stable than the corresponding duplexes. The poor stabilization of these structures limits their practical applications under physiological conditions. To understand the factors effect on the stabilization of RNA triplexes by octahedral ruthenium(II) complexes, the interactions of [RuL2(uip)](2+) {where L = 2,2'-bipyridine (bpy) or 1,10-phenanthroline phen, uip = 2-(5-uracil)-1H-imidazo[4,5-f][1,10]phenanthroline} with the RNA triplex poly(U)•poly(A)*poly(U) are examined by spectrophotometry, spectrofluorometry, circular dichroism, and viscosimetry in this work. The main results obtained here suggest that the third-strand stabilization depends on the hydrophobicity effects of ancillary ligands bpy and phen.
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Affiliation(s)
- Xiao-Jun He
- Key Lab of Environment-Friendly Chemistry and Application in Ministry of Education, Xiangtan University , Xiangtan 411105, PR China
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