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Wang Z, Zhang D, Qiu X, Inuzuka H, Xiong Y, Liu J, Chen L, Chen H, Xie L, Kaniskan HÜ, Chen X, Jin J, Wei W. Structurally Specific Z-DNA Proteolysis Targeting Chimera Enables Targeted Degradation of Adenosine Deaminase Acting on RNA 1. J Am Chem Soc 2024; 146:7584-7593. [PMID: 38469801 PMCID: PMC10988290 DOI: 10.1021/jacs.3c13646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Given the prevalent advancements in DNA- and RNA-based PROTACs, there remains a significant need for the exploration and expansion of more specific DNA-based tools, thus broadening the scope and repertoire of DNA-based PROTACs. Unlike conventional A- or B-form DNA, Z-form DNA is a configuration that exclusively manifests itself under specific stress conditions and with specific target sequences, which can be recognized by specific reader proteins, such as ADAR1 or ZBP1, to exert downstream biological functions. The core of our innovation lies in the strategic engagement of Z-form DNA with ADAR1 and its degradation is achieved by leveraging a VHL ligand conjugated to Z-form DNA to recruit the E3 ligase. This ingenious construct engendered a series of Z-PROTACs, which we utilized to selectively degrade the Z-DNA-binding protein ADAR1, a molecule that is frequently overexpressed in cancer cells. This meticulously orchestrated approach triggers a cascade of PANoptotic events, notably encompassing apoptosis and necroptosis, by mitigating the blocking effect of ADAR1 on ZBP1, particularly in cancer cells compared with normal cells. Moreover, the Z-PROTAC design exhibits a pronounced predilection for ADAR1, as opposed to other Z-DNA readers, such as ZBP1. As such, Z-PROTAC likely elicits a positive immunological response, subsequently leading to a synergistic augmentation of cancer cell death. In summary, the Z-DNA-based PROTAC (Z-PROTAC) approach introduces a modality generated by the conformational change from B- to Z-form DNA, which harnesses the structural specificity intrinsic to potentiate a selective degradation strategy. This methodology is an inspiring conduit for the advancement of PROTAC-based therapeutic modalities, underscoring its potential for selectivity within the therapeutic landscape of PROTACs to target undruggable proteins.
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Affiliation(s)
- Zhen Wang
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, United States
| | - Dingpeng Zhang
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02215, United States
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02215, United States
| | - Xing Qiu
- Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences, Oncological Sciences and Neuroscience, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Hiroyuki Inuzuka
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, United States
| | - Yan Xiong
- Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences, Oncological Sciences and Neuroscience, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Jing Liu
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, United States
| | - Li Chen
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, United States
| | - He Chen
- Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences, Oncological Sciences and Neuroscience, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Ling Xie
- Department of Biochemistry & Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - H Ümit Kaniskan
- Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences, Oncological Sciences and Neuroscience, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Xian Chen
- Department of Biochemistry & Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 United States
| | - Jian Jin
- Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences, Oncological Sciences and Neuroscience, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, United States
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Bhanjadeo MM, Nial PS, Sathyaseelan C, Singh AK, Dutta J, Rathinavelan T, Subudhi U. Biophysical interaction between lanthanum chloride and (CG) n or (GC) n repeats: A reversible B-to-Z DNA transition. Int J Biol Macromol 2022; 216:698-709. [PMID: 35809677 DOI: 10.1016/j.ijbiomac.2022.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/30/2022] [Accepted: 07/03/2022] [Indexed: 11/24/2022]
Abstract
The transition from right-handed to left-handed DNA is not only acts as the controlling factor for switching gene expression but also has equal importance in designing nanomechanical devices. The (CG)n and (GC)n repeat sequences are well known model molecules to study B-Z transition in the presence of higher concentration of monovalent cations. In this communication, we report a cyclic transition in (CG)6 DNA using millimolar concentration of trivalent lanthanide salt LaCl3. The controlled and reversible transition was seen in (CG)12, and (GC)12 DNA employing CD spectroscopy. While LaCl3 failed to induce B-Z transition in shorter oligonucleotides such as (CG)3 and (GC)3, a smooth B-Z transition was recorded for (CG)6, (CG)12 and (GC)12 sequences. Interestingly, the phenomenon was reversible (Z-B transition) with addition of EDTA. Particularly, two rounds of cyclic transition (B-Z-B-Z-B) have been noticed in (CG)6 DNA in presence of LaCl3 and EDTA which strongly suggest that B-Z transition is reversible in short repeat sequences. Thermal melting and annealing behaviour of B-DNA are reversible while the thermal melting of LaCl3-induced Z-DNA is irreversible which suggest a stronger binding of LaCl3 to the phosphate backbone of Z-DNA. This was further supported by isothermal titration calorimetric study. Molecular dynamics (MD) simulation indicates that the mode of binding of La3+ (of LaCl3) with d(CG)8.d(CG)8 is through the minor groove, wherein, 3 out of 11 La3+ bridge the anionic oxygens of the complementary strands. Such a tight coordination of La3+ with the anionic oxygens at the minor groove surface may be the reason for the experimentally observed irreversibility of LaCl3-induced Z-DNA seen in longer DNA fragments. Thus, these results indicate LaCl3 can easily be adopted as an inducer of left-handed DNA in other short oligonucleotides sequences to facilitate the understanding of the molecular mechanism of B-Z transition.
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Affiliation(s)
- Madhabi M Bhanjadeo
- DNA Nanotechnology & Application Laboratory, CSIR-Institute of Minerals & Materials Technology, Bhubaneswar 751 013, India; Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh, India
| | - Partha S Nial
- DNA Nanotechnology & Application Laboratory, CSIR-Institute of Minerals & Materials Technology, Bhubaneswar 751 013, India; Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh, India
| | - Chakkarai Sathyaseelan
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi Campus, Telangana 502285, India
| | - Ajit K Singh
- Structural Biology Laboratory, DBT-Institute of Life Sciences, Bhubaneswar 751023, India; Department of Pharmacology, University of Vermont College of Medicine, Burlington 05405, USA
| | - Juhi Dutta
- School of Chemical Sciences, National Institute of Science Education & Research, Bhubaneswar 752050, India; Homi Bhaba National Institute, Mumbai 400094, India
| | | | - Umakanta Subudhi
- DNA Nanotechnology & Application Laboratory, CSIR-Institute of Minerals & Materials Technology, Bhubaneswar 751 013, India; Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh, India.
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3
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Bhanjadeo MM, Baral B, Subudhi U. Sequence-specific B-to-Z transition in self-assembled DNA: A biophysical and thermodynamic study. Int J Biol Macromol 2019; 137:337-345. [DOI: 10.1016/j.ijbiomac.2019.06.166] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/17/2019] [Accepted: 06/23/2019] [Indexed: 12/20/2022]
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Chemical-induced formation of BZ-junction with base extrusion. Biochem Biophys Res Commun 2018; 508:1215-1220. [PMID: 30558789 DOI: 10.1016/j.bbrc.2018.12.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 12/05/2018] [Indexed: 11/24/2022]
Abstract
The crystal structure of BZ-junction reveals that left-handed Z-DNA stabilized by Z-DNA binding domain (Zα) is continuously stacked to right-handed B-DNA with AT bases' extrusion in the junction site. However, this structure might not fully represent the BZ-junction in solution due to the possibility of the junction formation either by crystal packing or Zα interaction. Therefore, we investigated BZ-junction in solution with chemical Z-DNA inducers using CD and 2-aminopurine base-extrusion assay. We confirmed the formation of Z-DNA and BZ-junction with base-extrusion by chemical Z-DNA inducers. However, neither typical Z-DNA nor base-extrusion could be detected with some inducers such as spermine, suggesting that the energy barrier for the formation of the BZ junction might vary depending on the Z-DNA induction conditions.
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Sunami T, Chatake T, Kono H. DNA conformational transitions inferred from re-evaluation of m|F o| - D|F c| electron-density maps. Acta Crystallogr D Struct Biol 2017; 73:600-608. [PMID: 28695860 PMCID: PMC5505156 DOI: 10.1107/s2059798317007707] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 05/24/2017] [Indexed: 11/30/2022] Open
Abstract
Conformational flexibility of DNA plays important roles in biological processes such as transcriptional regulation and DNA packaging etc. To understand the mechanisms of these processes, it is important to analyse when, where and how DNA shows conformational variations. Recent analyses have indicated that conventional refinement methods do not always provide accurate models of crystallographic heterogeneities and that some information on polymorphism has been overlooked in previous crystallographic studies. In the present study, the m|Fo| - D|Fc| electron-density maps of double-helical DNA crystal structures were calculated at a resolution equal to or better than 1.5 Å and potential conformational transitions were found in 27% of DNA phosphates. Detailed analyses of the m|Fo| - D|Fc| peaks indicated that some of these unassigned densities correspond to ZI ↔ ZII or A/B → BI conformational transitions. A relationship was also found between ZI/ZII transitions and metal coordination in Z-DNA from the detected peaks. The present study highlights that frequent transitions of phosphate backbones occur even in crystals and that some of these transitions are affected by the local molecular environment.
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Affiliation(s)
- Tomoko Sunami
- Molecular Modeling and Simulation Group, National Institutes for Quantum and Radiological Science and Technology, 8-1-7 Umemidai, Kizugawa 619-0215, Japan
| | - Toshiyuki Chatake
- Research Reactor Institute, Kyoto University, 2 Asashironishi, Kumatori, Osaka 590-0494, Japan
| | - Hidetoshi Kono
- Molecular Modeling and Simulation Group, National Institutes for Quantum and Radiological Science and Technology, 8-1-7 Umemidai, Kizugawa 619-0215, Japan
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Bhanjadeo MM, Nayak AK, Subudhi U. Cerium chloride stimulated controlled conversion of B-to-Z DNA in self-assembled nanostructures. Biochem Biophys Res Commun 2017; 482:916-921. [DOI: 10.1016/j.bbrc.2016.11.133] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 11/24/2016] [Indexed: 01/01/2023]
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Lanthanum induced B-to-Z transition in self-assembled Y-shaped branched DNA structure. Sci Rep 2016; 6:26855. [PMID: 27241949 PMCID: PMC4886512 DOI: 10.1038/srep26855] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/05/2016] [Indexed: 11/30/2022] Open
Abstract
Controlled conversion of right-handed B-DNA to left-handed Z-DNA is one of the greatest conformational transitions in biology. Recently, the B-Z transition has been explored from nanotechnological points of view and used as the driving machinery of many nanomechanical devices. Using a combination of CD spectroscopy, fluorescence spectroscopy, and PAGE, we demonstrate that low concentration of lanthanum chloride can mediate B-to-Z transition in self-assembled Y-shaped branched DNA (bDNA) structure. The transition is sensitive to the sequence and structure of the bDNA. Thermal melting and competitive dye binding experiments suggest that La3+ ions are loaded to the major and minor grooves of DNA and stabilize the Z-conformation. Our studies also show that EDTA and EtBr play an active role in reversing the transition from Z-to-B DNA.
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Pietropaolo A, D'urso A, Purrello R, Berova N. Effect of Different Z-Inducers on the Stabilization of Z Portion in BZ-DNA Sequence: Correlation Between Experimental and Simulation Data. Chirality 2015; 27:773-8. [PMID: 26365889 DOI: 10.1002/chir.22502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 07/24/2015] [Accepted: 07/25/2015] [Indexed: 12/28/2022]
Abstract
In this study we show the outstanding agreement between simulation and experimental data concerning the efficient stabilization effect by NaCl of Z conformation. We demonstrate by circular dichroism (CD) experiments that Na(+) not only is able to induce a B to Z form transition in a short (GC)3 alternated portion of a sequence having 17 basis, but also is the best stabilizer in comparison with other Z inducers used (spermine and NiCl2). This result was confirmed by free energy calculations.
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Affiliation(s)
| | - Alessandro D'urso
- Department of Chemical Science, University of Catania, Catania, Italy
| | - Roberto Purrello
- Department of Chemical Science, University of Catania, Catania, Italy
| | - Nina Berova
- Department of Chemistry, Columbia University, New York, NY, USA
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Holmes AE, Choi JK, Francis J, D'Urso A, Balaz M. Sulfonated Ni(II)porphyrin improves the detection of Z-DNA in condensed and non-condensed BZB DNA sequences. J Inorg Biochem 2012; 110:18-20. [PMID: 22459169 DOI: 10.1016/j.jinorgbio.2012.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 01/31/2012] [Accepted: 02/01/2012] [Indexed: 11/26/2022]
Abstract
We report a very selective and sensitive spectroscopic detection of Z-DNA embedded in B-DNA in condensed as well as non-condensed DNA using anionic Ni(II) meso-tetrakis(4-sulphonatophenyl)porphyrin, NiTPPS. A combination of micromolar concentrations of Ni(II) and spermine(4+) allowed us to prepare left-handed Z-DNA in short oligonucleotides without DNA condensation. A strong induced circular dichroism (ICD) signal was observed in the visible absorption region when NiTPPS was added to BZ DNA (Z-DNA fragment located at the end of a B-DNA tract with one B/Z DNA junction) and BZB DNA (Z-DNA sequence embedded in B-DNA having two B/Z DNA junctions). Almost no ICD signal was detected when NiTPPS was added to B-DNA. NiTPPS showed different binding modes with condensed and non-condensed Z-DNAs and allowed the distinction between condensed Z-DNA (positive bisignate CD couplet) and non-condensed Z-DNA (negative bisignate CD couplet).
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Affiliation(s)
- Andrea E Holmes
- Department of Chemistry, Doane College, 1014 Boswell Ave, Crete, NE 68333, USA
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Wu Z, Tian T, Yu J, Weng X, Liu Y, Zhou X. Formation of Sequence-Independent Z-DNA Induced by a Ruthenium Complex at Low Salt Concentrations. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201104422] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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11
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Wu Z, Tian T, Yu J, Weng X, Liu Y, Zhou X. Formation of sequence-independent Z-DNA induced by a ruthenium complex at low salt concentrations. Angew Chem Int Ed Engl 2011; 50:11962-7. [PMID: 22009837 DOI: 10.1002/anie.201104422] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 09/12/2011] [Indexed: 01/07/2023]
Affiliation(s)
- Zhiguo Wu
- College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Wuhan University, Hubei, P.R. of China
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12
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D'Urso A, Holmes AE, Berova N, Balaz M, Purrello R. Z-DNA Recognition in B-Z-B Sequences by a Cationic Zinc Porphyrin. Chem Asian J 2011; 6:3104-9. [DOI: 10.1002/asia.201100161] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Indexed: 11/08/2022]
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13
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Choi JK, Sargsyan G, Shabbir-Hussain M, Holmes AE, Balaz M. Chiroptical detection of condensed nickel(II)-Z-DNA in the presence of the B-DNA via porphyrin exciton coupled circular dichroism. J Phys Chem B 2011; 115:10182-8. [PMID: 21774503 DOI: 10.1021/jp2047213] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Here, we report a highly sensitive and specific chiroptical detection method of condensed left-handed Z-DNA in the presence of canonical right-handed B-DNA. The selective formation of a left-handed cytosine-guanine oligonucleotide (CG ODN) in the presence of a right-handed adenine-thymine oligonucleotide (AT ODN) was induced by millimolar concentrations of NiCl(2) and confirmed by electronic circular dichroism. The nickel(II) induced B- to Z-DNA transition of the CG ODN was accompanied by the concurrent condensation of the Ni(II)-Z-DNA, as confirmed by resonance light scattering, transmission spectroscopy, and centrifugation. The selective condensation of the CG ODN allowed its separation from the AT ODN using centrifugation. No structural changes were observed for the AT ODN upon addition of Ni(II). Anionic nickel(II) meso-tetra(4-sulfonatophenyl) porphyrin (NiTPPS) spectroscopically detected the left-handed Z-DNA in the Z-DNA/B-DNA mixture via a strong exciton coupled circular dichroism (ECCD) signal induced in the porphyrin Soret band absorption region. The bisignate ECCD signal originates from the assembly of achiral porphyrins into helical arrays by intermolecular interactions with the condensed Z-DNA scaffold. No induced CD signal was observed for the Ni(II)-B-DNA-NiTPPS complex. Hence, an unambiguous spectroscopic recognition of Ni(II) induced condensed Z-DNA in the presence of B-DNA is possible. The sensitivity of this chiroptical method was as low as 5% of the Z-DNA (4.4 μmol base pair concentration) in the presence of 95% B-DNA (80 μmol). Thus, NiTPPS is a highly sensitive probe for applications in biosensing via the CD signal amplification.
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Affiliation(s)
- Jung Kyu Choi
- Department of Chemistry, University of Wyoming, 1000 East University Avenue, Laramie, Wyoming 82071, USA
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Airoldi M, Gennaro G, Giomini M, Giuliani AM, Giustini M, Palazzo G. The CdCl2 effects on synthetic DNAs encaged in the nanodomains of a cationic water-in-oil microemulsion. Phys Chem Chem Phys 2011; 13:12293-304. [PMID: 21643617 DOI: 10.1039/c1cp20770a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The present work is dedicated to the study of the interactions of CdCl(2) with the synthetic polynucleotides polyAT and polyGC confined in the nanoscopic aqueous compartment of the water-in-oil microemulsion CTAB/pentanol/hexane/water, with the goal to mimic in vitro the situation met by the nucleic acids in vivo. In biological structures, in fact, very long strings of nucleic acids are segregated into very small compartments having a radius exceedingly smaller than the length of the encapsulated macromolecule. For comparison, the behaviour of polyGC was also studied in aqueous solutions of matched composition. The conformational and thermal stabilities of both polynucleotides enclosed in the inner compartment of the microemulsion are scarcely affected by the presence of CdCl(2), whereas in solution immediate and large effects were observed also at room temperature. The lack of effects of CdCl(2) on the properties of the biopolymers entrapped in the aqueous core of the microemulsion has been attributed to the peculiar characteristics of the medium (low dielectric constant, in particular) which cause a total repression of the CdCl(2) dissociation that is not complete even in water. In fact, several of the numerous effects of CdCl(2) observed on the conformational stability of polyGC in aqueous solutions have also been ascribed to the limited dissociation of the cadmium salt.
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Affiliation(s)
- Marta Airoldi
- Dipartimento di Chimica S. Cannizzaro, Università di Palermo, Palermo, Italy
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15
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Renčiuk D, Kypr J, Vorlíčková M. CGG repeats associated with fragile X chromosome form left-handed Z-DNA structure. Biopolymers 2011; 95:174-81. [PMID: 20960567 DOI: 10.1002/bip.21555] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
This work is a continuation of our effort to determine the structure responsible for expansion of the (CGG)(n) motif that results in fragile X chromosome syndrome. In our previous report, we demonstrated that the structure adopted by an oligonucleotide with this repeat sequence is not a quadruplex as was suggested by others. Here we demonstrate that (CGG) runs adopt another anomalous arrangement-a left-handed Z-DNA structure. The Z-DNA formation was induced by high salt and millimolar concentrations of Ni(2+) ions and likelihood of its formation increased with increasing number of repeats. In an oligonucleotide in which the CGG runs were interrupted by AGG triplets, as is observed in genomes of healthy individuals, the hairpin conformation was stabilized and Z-DNA formation was hindered. We show here that methylation of the (CGG) runs markedly stabilized Z-DNA formation. We hypothesize that rather than in the expansion process the Z-DNA may be formed by long, expanded (CGG) stretches that become hypermethylated; this would inhibit transcription resulting in disease.
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Affiliation(s)
- Daniel Renčiuk
- Institute of Biophysics, v.v.i., Academy of Sciences of the Czech Republic, Kralovopolska 135, CZ-61265 Brno, Czech Republic
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Recognition of left-handed Z-DNA of short unmodified oligonucleotides under physiological ionic strength conditions. Biochem Biophys Res Commun 2010; 397:329-32. [PMID: 20510880 DOI: 10.1016/j.bbrc.2010.05.119] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 05/24/2010] [Indexed: 11/20/2022]
Abstract
The left-handed Z-DNA form of the short unmodified alternating guanine-cytosine oligonucleotides, 5'-(dGdC)(24) and 5'-(dGdC)(18), was selectively detected under physiological ionic strength and pH conditions using the anionic nickel(II) porphyrin, NiTPPS. No spectroscopic signal was observed for NiTPPS with any right-handed oligonucleotides under identical conditions. The 48mer 5'-(dGdC)(24) Z-form was detected at concentrations as low as 100nM. The binding of NiTPPS to the B- and Z-oligonucleotides was studied quantitatively by UV-vis absorption and circular dichroism spectroscopies. NiTPPS was found to be a universal DNA binder, with binding affinity and geometry depending on the ionic composition of the solution, rather than on the DNA helical twist. This is the first example of a successful spectroscopic detection of the Z-DNA of short unmodified oligonucleotides under physiological pH and ionic strength conditions.
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17
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Kypr J, Kejnovská I, Renciuk D, Vorlícková M. Circular dichroism and conformational polymorphism of DNA. Nucleic Acids Res 2009; 37:1713-25. [PMID: 19190094 PMCID: PMC2665218 DOI: 10.1093/nar/gkp026] [Citation(s) in RCA: 1272] [Impact Index Per Article: 84.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Here we review studies that provided important information about conformational properties of DNA using circular dichroic (CD) spectroscopy. The conformational properties include the B-family of structures, A-form, Z-form, guanine quadruplexes, cytosine quadruplexes, triplexes and other less characterized structures. CD spectroscopy is extremely sensitive and relatively inexpensive. This fast and simple method can be used at low- as well as high-DNA concentrations and with short- as well as long-DNA molecules. The samples can easily be titrated with various agents to cause conformational isomerizations of DNA. The course of detected CD spectral changes makes possible to distinguish between gradual changes within a single DNA conformation and cooperative isomerizations between discrete structural states. It enables measuring kinetics of the appearance of particular conformers and determination of their thermodynamic parameters. In careful hands, CD spectroscopy is a valuable tool for mapping conformational properties of particular DNA molecules. Due to its numerous advantages, CD spectroscopy significantly participated in all basic conformational findings on DNA.
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Affiliation(s)
- Jaroslav Kypr
- Institute of Biophysics, vvi Academy of Sciences of the Czech Republic, Brno, Czech Republic.
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18
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Airoldi M, Gennaro G, Giomini M, Giuliani AM, Giustini M. Circular dichroism of polynucleotides: Interactions of NiCl2 with poly(dA-dT).poly(dA-dT) and poly(dG-dC).poly(dG-dC) in a water-in-oil microemulsion. Chirality 2008; 20:951-60. [PMID: 18246552 DOI: 10.1002/chir.20531] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The thermal behavior of the synthetic, high molecular weight, double stranded polynucleotides poly(dA-dT).poly(dA-dT) [polyAT] and poly(dG-dC).poly(dG-dC) [polyGC] solubilized in the aqueous core of the quaternary water-in-oil cationic microemulsion CTAB|n-pentanol|n-hexane|water in the presence of increasing amounts of NiCl(2) at several constant ionic strength values (NaCl) has been studied by means of circular dichroism and electronic absorption spectroscopies. In the microemulsive medium, both polynucleotides show temperature-induced modifications that markedly vary with both Ni(II) concentration and ionic strength. An increase of temperature causes denaturation of the polyAT duplex at low nickel concentrations, while more complex CD spectral modifications are observed at higher nickel concentrations and ionic strengths. By contrast, thermal denaturation is never observed for polyGC. At low Ni(II) concentrations, the increase of temperature induces conformational transitions from B-DNA to Z-DNA form, or, more precisely, to left-handed helical structures. In some cases, at higher nickel concentrations, the CD spectra suggest the presence of Z'-type forms of the polynucleotide.
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Affiliation(s)
- Marta Airoldi
- Dipartimento di Chimica Inorganica e Analitica Stanislao Cannizzaro, Università di Palermo, 90128 Palermo, Italy
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19
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Filimonova M, Gubskaya V, Davidov R, Garusov A, Nuretdinov I. Metal binding induces conversion of B- to the hybrid B-Z-form in natural DNA. Int J Biol Macromol 2008; 43:289-94. [PMID: 18644405 DOI: 10.1016/j.ijbiomac.2008.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 06/23/2008] [Accepted: 06/26/2008] [Indexed: 11/25/2022]
Abstract
Highly polymerized herring testis DNA of the random nucleotide sequence has been studied in solution by circular dichroism and ultra-violet absorption spectrometry under various experimental conditions. At low temperature upon addition of 0.05 M NaCl or 1.15 M MgSO4 the DNA formed a helix that belonged to the B-family. As the temperature was increased a transition from the pure B- to the hybrid B-Z-form occurred in the presence of 1.15 M MgSO4. This transition occurred over a large range of temperatures and corresponded to a non-cooperative conformational change. A similar DNA transition was induced with 0.098 mM Co(NH3)6Cl3. However, in the presence of 5.3 M NaCl the DNA conformation was not similar to that observed in 1.15 M MgSO4 or 0.098 mM Co(NH3)6Cl3 independently on the environmental temperature. In 5.3 M NaCl the DNA is thought to undergo a transition from one to another right-handed conformation that could be intermediate partially dehydrated conformer arising on the first step in the sequential transition to the dehydration of the polynucleotide. Our results show that a realistic model of native DNA, bearing Z-tracts embedded in B-helixes, can be obtained upon binding of alkaline earth or transition metals.
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Affiliation(s)
- Maria Filimonova
- Department of Microbiology, Kazan State University, Kremliovskaya st. 18, Kazan 420008, Russia.
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20
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Patel MM, Anchordoquy TJ. Ability of spermine to differentiate between DNA sequences--preferential stabilization of A-tracts. Biophys Chem 2006; 122:5-15. [PMID: 16504371 DOI: 10.1016/j.bpc.2006.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 02/07/2006] [Accepted: 02/07/2006] [Indexed: 11/16/2022]
Abstract
The regulatory roles fulfilled by polyamines by governance of chromatin structure are made possible by their strong association with cellular DNA, and hence by their ability to modulate DNA structure and function. Towards this end, it is crucial to understand the manifestation of sequence-dependent polyamine binding at the secondary and tertiary structural levels of DNA. This study utilizes circular dichroism (CD) and isothermal titration calorimetry (ITC) to address this relationship by using 20bp oligonucleotides with sequences-poly(dA):poly(dT), poly(dAdT):poly(dAdT), poly(dG):poly(dC), poly(dGdC):poly(dGdC)-that yield physiologically relevant structures, and poly(dIdC):poly(dIdC). CD studies show that at physiological ionic strength (150mM NaCl), spermine preferentially stabilizes A-tracts, and increases flexibility of the G-tract oligomer; the latter is also suggested by the larger change in entropy (DeltaS) of spermine binding to G-tracts. Given the chromatin destabilizing property of these sequences, these findings suggest a role for spermine in stabilization of non-nucleosomal A-tracts, and a compensating mechanism for incorporation of G-tracts in the chromatin structure. Other implications of these findings in sequence dependent DNA packaging are discussed.
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Affiliation(s)
- Mayank M Patel
- Department of Pharmaceutical Sciences, School of Pharmacy--C238, University of Colorado Health Sciences Center, 4200 E. Ninth Avenue, Denver, CO 80262, USA.
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21
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Kypr J, Stepán J, Chládková J, Vorlícková M. Circular dichroism spectroscopy analysis of conformational transitions of a 54 base pair DNA duplex composed of alternating CGCGCG and TATATA blocks. BIOSPECTROSCOPY 1999; 5:253-62. [PMID: 10478956 DOI: 10.1002/(sici)1520-6343(1999)5:4<253::aid-bspy6>3.0.co;2-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
CD spectroscopy was used to analyze conformational properties of a self-complementary 54-mer DNA composed of alternating (CG)3 and (TA)3 hexamers. NaCl induced the Z-form in poly(GC), but the 54-mer remained the B-form under the same conditions. The B-Z transition was induced only after the addition of NiCl2. However, the Z-form was adopted by the whole molecule, not by the (CG)3 blocks alone. Two orders of magnitude higher concentrations of NiCl2 were required to induce the Z-form in poly(AT). The Z-form was also induced in poly(GC) by CsF that switched poly(AT) into the X-form, which seems to be a solution counterpart of D-DNA. Under these conditions the CD spectrum of the 54-mer was consistent with the (TA)3 blocks being in the X-form and the (CG)3 blocks in the B-form. At high concentrations of ethanol or trifluoroethanol, poly(AT) was an A-form, while poly(GC) adopted either Z-form, A-form or Z'-form. At the high trifluoroethanol concentrations the 54-mer cooperatively switched into a conformation whose CD spectrum was most consistent with the A-form in the (TA)3 blocks and the Z'-form in the (CG)3 blocks. This suggests that the base pairs are tilted in the Z'-form as in the A-form. The present article illustrates that CD spectroscopy can provide interesting pieces of information about conformational isomerizations and coexistence of multiple conformations in DNA molecules containing blocks of different simple sequence repeats.
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Affiliation(s)
- J Kypr
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno
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22
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Vorlícková M. Conformational transitions of alternating purine-pyrimidine DNAs in perchlorate ethanol solutions. Biophys J 1995; 69:2033-43. [PMID: 8580346 PMCID: PMC1236436 DOI: 10.1016/s0006-3495(95)80073-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Conformational transitions of poly(dA-dC).poly(dG-dT), poly(dA-dT).poly(dA-dT), and other alternating purine-pyrimidine DNAs were studied in aqueous ethanol solutions containing molar concentrations of sodium perchlorate, which is a novel solvent stabilizing non-B duplexes of DNA. Using CD and UV absorption spectroscopies, we show that this solvent unstacks bases and unwinds the B-forms of the DNAs to transform them into the A-form or Z-form. In the absence of divalent cations poly(dA-dC).poly(dG-dT) can adopt both of these conformations. Its transition into the Z-form is induced at higher salt and lower ethanol concentrations, and at higher temperatures than the transition into the A-form. Submillimolar concentrations of NiCl2 induce a highly cooperative and slow A-Z transition or Z-Z' transition, which is fast and displays low cooperativity. Poly(dA-dT).poly(dA-dT) easily isomerizes into the A-form in perchlorate-ethanol solutions, whereas high perchlorate concentrations denature the polynucleotide, which then cannot adopt the Z-form. At low temperatures, however, NiCl2 also cooperatively induces the Z'-form in poly(dA-dT).poly(dA-dT). Poly(dI-dC).poly(dI-dC) is known to adopt an unusual B-form in low-salt aqueous solution, which is transformed into a standard B-form by the combination of perchlorate and ethanol. NiCl2 then transforms poly(dI-dC).poly(dI-dC) into the Z'-form, which is also adopted by poly(dI-br5dC).poly(dI-br5dC).
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Affiliation(s)
- M Vorlícková
- Institute of Biophysics, Czech Academy of Sciences, Brno, Czech Republic
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23
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Sági J, Szemzö A, Otvös L, Vorlícková M, Kypr J. Destabilization of the duplex and the high-salt Z-form of poly(dG-methyl5dC) by substitution of ethyl for the 5-methyl group. Int J Biol Macromol 1991; 13:329-36. [PMID: 1772823 DOI: 10.1016/0141-8130(91)90013-k] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The B-to-Z conformational transition of poly(dG-dC) is highly promoted by 5-methyl substitution of the dC moiety, i.e. in poly(dG-methyl5dC). By the synthesis of a new poly(dG-dC) analogue, poly(dG-ethyl5dC), the effect of a longer alkyl-chain substituent of dC on structure and conformation has been studied with ultraviolet absorption melting profiles and circular dichroism spectroscopy. The 5-ethyl substituent in poly(dG-ethyl5dC) destabilizes the duplex structure against thermal denaturation compared with both poly(dG-methyl5dC) and poly(dG-dC). C.d. studies also reveal that for the high-salt B-Z transition of poly(dG-ethyl5dC) a higher NaCl concentration is required than for that of poly(dG-methyl5dC), although much lower than for poly(dG-dC). However low-salt Z-DNA in poly(dG-ethyl5dC) shows unique features, e.g. it needs no divalent cations to be stable. The low-salt B-Z transition of poly(dG-ethyl5dC) can also be observed by the absorption-temperature melting profile, in contrast to both poly(dG-methyl5dC) and poly(dG-dC). The effects of MgCl2 concentration, temperature, acid pH and trifluorethanol on the conformation of poly(dG-ethyl5dC) have also been determined.
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Affiliation(s)
- J Sági
- Central Research Institute for Chemistry, Hungarian Academy of Sciences, Budapest
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24
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Vorlícková M, Sági J. Transitions of poly(dI-dC), poly(dI-methyl5dC) and poly(dI-bromo5dC) among and within the B-, Z-, A- and X-DNA families of conformations. Nucleic Acids Res 1991; 19:2343-7. [PMID: 2041775 PMCID: PMC329441 DOI: 10.1093/nar/19.9.2343] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
It is shown, using circular dichroism spectroscopy, that poly(dI-dC) is capable to isomerize into both Z-DNA and A-DNA in concentrated NaCl + NiCl2 and trifluoroethanol solutions, respectively. This polynucleotide also undergoes a cooperative, two-state transition in ethanol into a structure which most probably is a canonical B-DNA. This implies that the conformation of poly(dI-dC) is unusual in low-salt aqueous solution. The canonical B-DNA is also adopted by poly(dI-methyl5dC) in trifluoroethanol while this polynucleotide adopts Z-DNA not only in NaCl + NiCl2 but also in the presence of MgCl2. Poly(dI-methyl5dC) partially adopts X-DNA in concentrated CsF and mainly ethanolic solutions. Poly(dI-bromo5dC) isomerizes into Z-DNA not only in concentrated NaCl even in the absence of NiCl2 but also in concentrated MgCl2. This polynucleotide transforms between two distinct variants of Z-DNA in ethanol or trifluoroethanol solutions.
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Affiliation(s)
- M Vorlícková
- Institute of Biophysics, Czechoslovak Academy of Sciences, Brno
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