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Wang Q, Lü LB, Tao Z, Sun T, Tang Q, Huang Y. The pH and mercury ion stimuli-responsive supramolecular assemblies of cucurbit[7]uril and Hoechst 33342. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 254:119656. [PMID: 33744695 DOI: 10.1016/j.saa.2021.119656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/18/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
In the present work, we have investigated the effect of pH and mercury ions on the host-guest complex formed between cucurbit[7]uril (Q[7]) and Hoechst 33342 (H33342). 1H NMR, UV-vis and fluorescence spectroscopy revealed that acid/base stimulation could change the binding stoichiometry between Q[7] and H33342. The results suggest that two complexation equilibria (1:1 and 2:1) may exist between H33342 and Q[7] at pH 2.0 and 4.5, respectively. However, a 1:1 host-guest complex was formed between H33342 and Q[7] at pH 7.0 and 10.0. Q[7] shows differential affinities for the protonated and neutral forms of H33342 dye. Moreover, the switching between H33342∙2H+@2Q[7](1:2) at pH 4.5 and H33342∙H+@Q[7](1:1) at pH 7.0 was reversible. Furthermore, as a metal stimulus, Hg2+ ions could push (i) Q[7] from the piperazine ring to the benzimidazole position with a 1:1 guest-host ratio and (ii) a second Q[7] onto the ethyl position with a 1:2 guest-host stoichiometry. This stimulus response system will have potential applications in the field of molecular switch design.
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Affiliation(s)
- Qin Wang
- Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, China.
| | - Li-Bing Lü
- Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, China.
| | - Zhu Tao
- Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, China.
| | - Tao Sun
- Key Laboratory of Guizhou High Performance Computational Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, China.
| | - Qing Tang
- Department College of Tobacco Science, Guizhou University, Guiyang 550025, China.
| | - Ying Huang
- Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, China; The Engineering and Research Center for Southwest Bio-Pharmaceutical Resources of National Education Ministry of China, Guizhou University, Guiyang 550025, China.
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Issar U, Kumari T, Arora R, Kakkar R. Conformational properties of DNA minor groove binder Hoechst 33258 in gas phase and in aqueous solution. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.05.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Casanovas J, Jacquemin D, Perpète EA, Alemán C. Fluorescein isothiocyanate: Molecular characterization by theoretical calculations. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2008.10.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Sando S, Narita A, Hayami M, Aoyama Y. Tuning the Hoechst Dye into Color-changing Fluorescent pH Indicator in an Acidic Range. CHEM LETT 2008. [DOI: 10.1246/cl.2008.246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Chaudhuri P, Ganguly B, Bhattacharya S. An Experimental and Computational Analysis on the Differential Role of the Positional Isomers of Symmetric Bis-2-(pyridyl)-1H-benzimidazoles as DNA Binding Agents. J Org Chem 2007; 72:1912-23. [PMID: 17305396 DOI: 10.1021/jo0619433] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Three symmetrical positional isomers of bis-2-(n-pyridyl)-1H-benzimidazoles (n=2, 3, 4) were synthesized and DNA binding studies were performed with these isomeric derivatives. Like bisbenzimidazole compound Hoechst 33258, these molecules also demonstrate AT-specific DNA binding. The binding affinities of 3-pyridine (m-pyben) and 4-pyridine (p-pyben) derivatized bisbenzimidazoles to double-stranded DNA were significantly higher compared to 2-pyridine derivatized benzimidazole o-pyben. This has been established by combined experimental results of isothermal fluorescence titration, circular dichroism, and thermal denaturation of DNA. To rationalize the origin of their differential binding characteristics with double-stranded DNA, computational structural analyses of the uncomplexed ligands were performed using ab initio/Density Functional Theory. The molecular conformations of the symmetric head-to-head bisbenzimidazoles have been computed. The existence of intramolecular hydrogen bonding was established in o-pyben, which confers a conformational rigidity to the molecule about the bond connecting the pyridine and benzimidazole units. This might cause reduction in its binding affinity to double-stranded DNA compared to its para and meta counterparts. Additionally, the predicted stable conformations for p-, m-, and o-pyben at the B3LYP/6-31G* and RHF/6-31G* levels were further supported by experimental pKa determination. The results provide important information on the molecular recognition process of such symmetric head to head bisbenzimidazoles toward duplex DNA.
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Affiliation(s)
- Padmaparna Chaudhuri
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012, India
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Alemán C, Namba AM, Casanovas J. Acid-Base and Electronic Structure-Dependent Properties of Hoechst 33342. J Biomol Struct Dyn 2005; 23:29-36. [PMID: 15918674 DOI: 10.1080/07391102.2005.10507044] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
An ab initio quantum mechanical study of the bis-benzimidazole derivative Hoechst 33342 is presented. Specifically, we report on the molecular geometry, proton affinity, gas-phase basicity, hydration, pKa, and molecular interaction potential map of Hoechst 33342 and the forms obtained by its protonation and deprotonation. Results have been compared with those obtained for Hoechst 33258 to analyze the influence of the chemical structure on the properties of this bis-benzimidazole derivative. Finally, the connection of some theoretical predictions with experimental evidences has been examined.
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Affiliation(s)
- Carlos Alemán
- Departament d'Enginyeria Quimica, E.T.S. d'Enginyeria Industrial de Barcelona, Universitat Politecnica de Catalunya, Barcelona E-08028, Spain.
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Gabelica V, Galic N, Rosu F, Houssier C, De Pauw E. Influence of response factors on determining equilibrium association constants of non-covalent complexes by electrospray ionization mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2003; 38:491-501. [PMID: 12794869 DOI: 10.1002/jms.459] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A method for determining the equilibrium association constant of a complexation reaction A + B left harpoon over right harpoon AB by electrospray ionization mass spectrometry is described. The method consists in measuring the relative intensities of the peaks corresponding to A and to AB in equimolar A-B solutions at different concentrations C(0). The results are fitted by a non-linear least-squares procedure, with the two variable parameters being the equilibrium association constant K(a) and a factor R, defined by I(AB)/I(A) = R x [AB]/[A]. The factor R is the ratio between the response factors of AB and A, and corrects for the relative electrospray responses of the complex and the free substrate A, mass discrimination of instrumental origin and/or moderate in-source dissociation. The method is illustrated with the following two systems: complexes between a double-stranded 12-base pair oligonucleotide and minor groove binders, and cyclodextrin complexes with alpha,omega-dicarboxylic acids. For the oligonucleotide complexes, it is found that the response of the complex is not dramatically different to the response of the free oligonucleotide duplex, as the double helix conformation is disturbed by the drug only to a minor extent. In the case of cyclodextrin complexes, these complexes were found to have a much higher response than free cyclodextrin. This may be due to the fact that cyclodextrin is neutral in solution, whereas the complex is charged, but it can also stem from the fact that a significant proportion of the complex is in a non-inclusion geometry. The present method requires the exact determination of the concentrations of the reactants and is applicable to 1 : 1 complexes.
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Affiliation(s)
- Valérie Gabelica
- Laboratoire de Spectrométrie de Masse, Département de Chimie, Université de Liège, B-4000 Liège, Belgium.
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Alemán C, Adhikary A, Zanuy D, Casanovas J. On the protonation equilibrium for the benzimidazole derivative Hoechst 33258: an electronic molecular orbital study. J Biomol Struct Dyn 2002; 20:301-10. [PMID: 12354081 DOI: 10.1080/07391102.2002.10506845] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Hoechst 33258 and its deprotonated forms have been examined in the gas-phase and in solution using quantum mechanical methods. Ab initio calculations at the HF level have been used to investigate the more relevant geometrical trends of such species, while proton affinities and gas-phase basicities were derived from B3LYP and MP2 electronic energies. Solvation energies were calculated using a dielectric continuum model: MST. The Delta(p)K(a) values were estimated by combining the gas-phase basicities and the free energies of solvation. Comparison of these Delta(p)K(a) values with experimentally reported data have been used to highlight the advantages and limitations of this strategy.
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Affiliation(s)
- Carlos Alemán
- Departament d'Enginyeria Química, E.T.S. d'Enginyers Industrials de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, Barcelona E-08028, Spain.
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Ismail MA, Rodger PM, Rodger A. Drug Self-Assembly on DNA: Sequence Effects withtrans-bis-(4-N-methylpyridiniumyl)diphenyl Porphyrin and Hoechst 33258. J Biomol Struct Dyn 2000; 17 Suppl 1:335-48. [DOI: 10.1080/07391102.2000.10506639] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Aymami J, Nunn CM, Neidle S. DNA minor groove recognition of a non-self-complementary AT-rich sequence by a tris-benzimidazole ligand. Nucleic Acids Res 1999; 27:2691-8. [PMID: 10373586 PMCID: PMC148478 DOI: 10.1093/nar/27.13.2691] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The crystal structure of the non-self-complementary dodecamer DNA duplex formed by d(CG[5BrC]ATAT-TTGCG) and d(CGCAAATATGCG) has been solved to 2.3 A resolution, together with that of its complex with the tris-benzimidazole minor groove binding ligand TRIBIZ. The inclusion of a bromine atom on one strand in each structure enabled the possibility of disorder to be discounted. The native structure has an exceptional narrow minor groove, of 2.5-2.6 A in the central part of the A/T region, which is increased in width by approximately 0.8 A on drug binding. The ligand molecule binds in the central part of the sequence. The benzimidazole subunits of the ligand participate in six bifurcated hydrogen bonds with A:T base pair edges, three to each DNA strand. The presence of a pair of C-H...O hydrogen bonds has been deduced from the close proximity of the pyrrolidine group of the ligand to the TpA step in the sequence.
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Affiliation(s)
- J Aymami
- The CRC Biomolecular Structure Unit, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
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Tang GQ, Tanaka N, Kunugi S. Salt Effects on Fluorescence Spectral Shifts of DNA-Bound Hoechst 33258 and Reaction Volumes of the Minor Groove Binding. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1999. [DOI: 10.1246/bcsj.72.1129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Willmore E, Frank AJ, Padget K, Tilby MJ, Austin CA. Etoposide targets topoisomerase IIalpha and IIbeta in leukemic cells: isoform-specific cleavable complexes visualized and quantified in situ by a novel immunofluorescence technique. Mol Pharmacol 1998; 54:78-85. [PMID: 9658192 DOI: 10.1124/mol.54.1.78] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have shown that both DNA topoisomerase (topo) IIalpha and beta are in vivo targets for etoposide using a new assay which directly measures topo IIalpha and beta cleavable complexes in individual cells after treatment with topo II targeting drugs. CCRF-CEM human leukemic cells were exposed to etoposide for 2 hr, then embedded in agarose on microscope slides before cell lysis. DNA from each cell remained trapped in the agarose and covalently bound topo II molecules from drug-stabilized cleavable complexes remained associated with the DNA. The covalently bound topo II was detected in situ by immunofluorescence. Isoform-specific covalent complexes were detected with antisera specific for either the alpha or beta isoform of topo II followed by a fluorescein isothiocyanate-conjugated second antibody. DNA was detected using the fluorescent stain Hoechst 33258. A cooled slow scan charged coupled device camera was used to capture images. A dose-dependent increase in green immunofluorescence was observed when using antisera to either the alpha or beta isoforms of topo II, indicating that both isoforms are targets for etoposide. We have called this the TARDIS method, for trapped in agarose DNA immunostaining. Two key advantages of the TARDIS method are that it is isoform-specific and that it requires small numbers of cells, making it suitable for analysis of samples from patients being treated with topo II-targeting drugs. The isoform specificity will enable us to extend our understanding of the mechanism of interaction between topo II-targeting agents and their target, the two human isoforms.
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Affiliation(s)
- E Willmore
- Department of Biochemistry and Genetics, The Medical School, The University of Newcastle-upon-Tyne, Newcastle-upon-Tyne NE2 4HH, United Kingdom
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