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Ranjan N, Arya DP. Parallel G-quadruplex recognition by neomycin. Front Chem 2023; 11:1232514. [PMID: 37671393 PMCID: PMC10475565 DOI: 10.3389/fchem.2023.1232514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/25/2023] [Indexed: 09/07/2023] Open
Abstract
G-quadruplex-forming nucleic acids have evolved to have applications in biology, drug design, sensing, and nanotechnology, to name a few. Together with the structural understanding, several attempts have been made to discover and design new classes of chemical agents that target these structures in the hope of using them as future therapeutics. Here, we report the binding of aminoglycosides, in particular neomycin, to parallel G-quadruplexes that exist as G-quadruplex monomers, dimers, or compounds that have the propensity to form dimeric G-quadruplex structures. Using a combination of calorimetric and spectroscopic studies, we show that neomycin binds to the parallel G-quadruplex with affinities in the range of Ka ∼ 105-108 M-1, which depends on the base composition, ability to form dimeric G-quadruplex structures, salt, and pH of the buffer used. At pH 7.0, the binding of neomycin was found to be electrostatically driven potentially through the formation of ion pairs formed with the quadruplex. Lowering the pH resulted in neomycin's association constants in the range of Ka ∼ 106-107 M-1 in a salt dependent manner. Circular dichroism (CD) studies showed that neomycin's binding does not cause a change in the parallel conformation of the G-quadruplex, yet some binding-induced changes in the intensity of the CD signals were seen. A comparative binding study of neomycin and paromomycin using d(UG4T) showed paromomycin binding to be much weaker than neomycin, highlighting the importance of ring I in the recognition process. In toto, our results expanded the binding landscape of aminoglycosides where parallel G-quadruplexes have been discovered as one of the high-affinity sites. These results may offer a new understanding of some of the undesirable functions of aminoglycosides and help in the design of aminoglycoside-based G-quadruplex binders of high affinity.
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Affiliation(s)
| | - Dev P. Arya
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC, United States
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2
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Recoding of Nonsense Mutation as a Pharmacological Strategy. Biomedicines 2023; 11:biomedicines11030659. [PMID: 36979640 PMCID: PMC10044939 DOI: 10.3390/biomedicines11030659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 02/24/2023] Open
Abstract
Approximately 11% of genetic human diseases are caused by nonsense mutations that introduce a premature termination codon (PTC) into the coding sequence. The PTC results in the production of a potentially harmful shortened polypeptide and activation of a nonsense-mediated decay (NMD) pathway. The NMD pathway reduces the burden of unproductive protein synthesis by lowering the level of PTC mRNA. There is an endogenous rescue mechanism that produces a full-length protein from a PTC mRNA. Nonsense suppression therapies aim to increase readthrough, suppress NMD, or are a combination of both strategies. Therefore, treatment with translational readthrough-inducing drugs (TRIDs) and NMD inhibitors may increase the effectiveness of PTC suppression. Here we discuss the mechanism of PTC readthrough and the development of novel approaches to PTC suppression. We also discuss the toxicity and bioavailability of therapeutics used to stimulate PTC readthrough.
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3
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Rangel VM, Gu L, Chen G, Chen QH, Xue L. 5-Substituted 3, 3', 4', 7-tetramethoxyflavonoids - A novel class of potent DNA triplex specific binding ligands. Bioorg Med Chem Lett 2022; 61:128608. [PMID: 35143982 DOI: 10.1016/j.bmcl.2022.128608] [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: 11/23/2021] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 11/18/2022]
Abstract
Herein, we present a class of potent triplex DNA binding ligands derived from the natural product quercetin, which is the first of its kind that has ever been reported in the literature. The binding of 5-substituted quercetin derivatives (3, 3', 4', 7-tetramethoxyflavonoids) to triplex and duplex DNA was investigated using several biophysical tools, including thermal denaturation monitored by UV, circular dichroism, differential scanning calorimetry, and isothermal titration calorimetry. Experimental data reveal that several 5-substituted 3, 3', 4', 7-tetramethoxyflavonoids have remarkable effects on binding to DNA triple helices, and they do not influence the double-helical DNA structures. A few derivatives such as compounds 5 and 7 have comparable (if not better) binding affinities to neomycin, a well-known DNA triplex binding ligand, under the same conditions. The amino-containing side chains at the 5-position of 3, 3', 4', 7-tetramethoxyflavonoids are crucial for the observed binding affinity and specificity.
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Affiliation(s)
- Vanessa M Rangel
- Department of Chemistry, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211, USA
| | - Landy Gu
- Department of Chemistry, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211, USA
| | - Guanglin Chen
- Department of Chemistry, California State University, Fresno, CA 93740, USA
| | - Qiao-Hong Chen
- Department of Chemistry, California State University, Fresno, CA 93740, USA
| | - Liang Xue
- Department of Chemistry, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211, USA.
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4
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Bellucci MC, Volonterio A. Aminoglycosides: From Antibiotics to Building Blocks for the Synthesis and Development of Gene Delivery Vehicles. Antibiotics (Basel) 2020; 9:E504. [PMID: 32796727 PMCID: PMC7459817 DOI: 10.3390/antibiotics9080504] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/29/2020] [Accepted: 08/07/2020] [Indexed: 02/06/2023] Open
Abstract
Aminoglycosides are a class of naturally occurring and semi synthetic antibiotics that have been used for a long time in fighting bacterial infections. Due to acquired antibiotic resistance and inherent toxicity, aminoglycosides have experienced a decrease in interest over time. However, in the last decade, we are seeing a renaissance of aminoglycosides thanks to a better understanding of their chemistry and mode of action, which had led to new trends of application. The purpose of this comprehensive review is to highlight one of these new fields of application: the use of aminoglycosides as building blocks for the development of liposomal and polymeric vectors for gene delivery. The design, synthetic strategies, ability to condensate the genetic material, the efficiency in transfection, and cytotoxicity as well as when available, the antibacterial activity of aminoglycoside-based cationic lipids and polymers are covered and critically analyzed.
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Affiliation(s)
- Maria Cristina Bellucci
- Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy;
| | - Alessandro Volonterio
- Department of Chemistry, Material and Chemical Engineer “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131 Milano, Italy
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5
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Aradi K, Di Giorgio A, Duca M. Aminoglycoside Conjugation for RNA Targeting: Antimicrobials and Beyond. Chemistry 2020; 26:12273-12309. [PMID: 32539167 DOI: 10.1002/chem.202002258] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/11/2020] [Indexed: 01/04/2023]
Abstract
Natural aminoglycosides are therapeutically useful antibiotics and very efficient RNA ligands. They are oligosaccharides that contain several ammonium groups able to interfere with the translation process in prokaryotes upon binding to bacterial ribosomal RNA (rRNA), and thus, impairing protein synthesis. Even if aminoglycosides are commonly used in therapy, these RNA binders lack selectivity and are able to bind to a wide number of RNA sequences/structures. This is one of the reasons for their toxicity and limited applications in therapy. At the same time, the ability of aminoglycosides to bind to various RNAs renders them a great source of inspiration for the synthesis of new binders with improved affinity and specificity toward several therapeutically relevant RNA targets. Thus, a number of studies have been performed on these complex and highly functionalized compounds, leading to the development of various synthetic methodologies toward the synthesis of conjugated aminoglycosides. The aim of this review is to highlight recent progress in the field of aminoglycoside conjugation, paying particular attention to modifications performed toward the improvement of affinity and especially to the selectivity of the resulting compounds. This will help readers to understand how to introduce a desired chemical modification for future developments of RNA ligands as antibiotics, antiviral, and anticancer compounds.
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Affiliation(s)
- Klara Aradi
- Université Côte d'Azur, CNRS, Institute of Chemistry of Nice (ICN), 06100, Nice, France
| | - Audrey Di Giorgio
- Université Côte d'Azur, CNRS, Institute of Chemistry of Nice (ICN), 06100, Nice, France
| | - Maria Duca
- Université Côte d'Azur, CNRS, Institute of Chemistry of Nice (ICN), 06100, Nice, France
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6
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Büyükgüzel K, Büyükgüzel E, Chudzińska E, Lewandowska-Wosik A, Gaj R, Adamski Z. Drosophila melanogaster Response to Feeding with Neomycin-Based Medium Expressed in Fluctuating Asymmetry. INSECTS 2020; 11:E378. [PMID: 32570778 PMCID: PMC7348700 DOI: 10.3390/insects11060378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/08/2020] [Accepted: 06/15/2020] [Indexed: 11/16/2022]
Abstract
The fruit fly Drosophila melanogaster is a model species used for a wide range of studies. Contamination of Drosophila cultures with bacterial infection is common and is readily eradicated by antibiotics. Neomycin antibiotics can cause stress to D. melanogaster's larvae and imagoes, which may affect the interpretation of the results of research using culture from neomycin-based medium. In the present study, fluctuating asymmetry (FA), one of the important bioindicators of stress, was measured. Larvae and imagoes of a wild-type D. melanogaster strain were exposed to various concentrations of neomycin. The size of anal papillae and selected wing veins were measured using scanning electron and light microscopy, respectively. Next, the FA was checked. The values obtained for larval anal papillae appeared to be concentration-dependant; the FA indices increased with the concentration of neomycin. The wing FA presented a large but variable correlation, depending on the measured vein. However, the mean length of veins was the highest for the control group, with neomycin-exposed groups showing lower values. The research showed that neomycin may cause sublethal stress in D. melanogaster, which manifests in increased FA indices. This suggests that neomycin can cause physiological and developmental stress in insects, which should be taken into account when interpreting the results of studies using these model organisms.
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Affiliation(s)
- Kemal Büyükgüzel
- Department of Biology, Faculty of Arts and Science, Zonguldak Bülent Ecevit University, 67100 Zonguldak, Turkey;
| | - Ender Büyükgüzel
- Department of Molecular Biology and Genetics, Faculty of Arts and Science, Zonguldak Bülent Ecevit University, 67100 Zonguldak, Turkey;
| | - Ewa Chudzińska
- Department of Genetics, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland; (E.C.); (A.L.-W.)
| | - Anetta Lewandowska-Wosik
- Department of Genetics, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland; (E.C.); (A.L.-W.)
| | - Renata Gaj
- Department of Agricultural Chemistry & Environmental Biogeochemistry, Poznan University of Life Science, 60-637 Poznań, Poland;
| | - Zbigniew Adamski
- Electron and Confocal Microscope Laboratory, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
- Department of Animal Physiology and Development, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
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7
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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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8
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Granqvist L, Tähtinen V, Virta P. Synthesis of Glycosidic (β-1''→6, 3' and 4') Site Isomers of Neomycin B and their Effect on RNA and DNA Triplex Stability. Molecules 2019; 24:molecules24030580. [PMID: 30736311 PMCID: PMC6385478 DOI: 10.3390/molecules24030580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 02/03/2019] [Accepted: 02/04/2019] [Indexed: 01/02/2023] Open
Abstract
Glycosidic (β-1''→6, 3' and 4') site isomers of neomycin B (i.e., neobiosamine (β-1''→6, 3' and 4') neamines) have been synthesized in a straightforward manner. Peracetylated neomycin azide was used as a common starting material to obtain neobiosamine glycosyl donor and 6, 3',4'-tri-O-acetyl neamine azide that after simple protecting group manipulation was converted to three different glycosyl acceptors (i.e., 5,6,4'-, 5,3',4'- and 5,6,3'-tri-O-acetyl neamine azide). Glycosylation between the neobiosamine glycosyl donor and the neamine-derived acceptors gave the protected pseudo-tetrasaccharides, which were converted, via global deprotection (deacetylation and reduction of the azide groups), to the desired site isomers of neomycin. The effect of these aminoglycosides on the RNA and DNA triplex stability was studied by UV-melting profile analysis.
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Affiliation(s)
- Lotta Granqvist
- Department of Chemistry, University of Turku, 20014 Turku, Finland.
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9
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Watkins D, Maiti K, Arya DP. Aminoglycoside Functionalization as a Tool for Targeting Nucleic Acids. Methods Mol Biol 2019; 1973:147-162. [PMID: 31016700 DOI: 10.1007/978-1-4939-9216-4_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Aminoglycoside functionalization as a tool for targeting natural and unnatural nucleic acids holds great promise in their development as diagnostic probes and medicinally relevant compounds. Simple synthetic procedures designed to easily and quickly manipulate amino sugar (neomycin, kanamycin) to more powerful and selective ligands are presented in this chapter. We describe representative procedures for (a) aminoglycoside conjugation and (b) preliminary screening for their nucleic acid binding and selectivity.
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Affiliation(s)
- Derrick Watkins
- Department of Chemistry, Clemson University, Clemson, SC, USA
| | | | - Dev P Arya
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC, USA.
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10
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Gómez Ramos LM, Degtyareva NN, Kovacs NA, Holguin SY, Jiang L, Petrov AS, Biesiada M, Hu MY, Purzycka KJ, Arya DP, Williams LD. Eukaryotic Ribosomal Expansion Segments as Antimicrobial Targets. Biochemistry 2017; 56:5288-5299. [PMID: 28895721 DOI: 10.1021/acs.biochem.7b00703] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Diversity in eukaryotic rRNA structure and function offers possibilities of therapeutic targets. Unlike ribosomes of prokaryotes, eukaryotic ribosomes contain species-specific rRNA expansion segments (ESs) with idiosyncratic structures and functions that are essential and specific to some organisms. Here we investigate expansion segment 7 (ES7), one of the largest and most variable expansions of the eukaryotic ribosome. We hypothesize that ES7 of the pathogenic fungi Candida albicans (ES7CA) could be a prototypic drug target. We show that isolated ES7CA folds reversibly to a native-like state. We developed a fluorescence displacement assay using an RNA binding fluorescent probe, F-neo. F-neo binds tightly to ES7CA with a Kd of 2.5 × 10-9 M but binds weakly to ES7 of humans (ES7HS) with a Kd estimated to be greater than 7 μM. The fluorescence displacement assay was used to investigate the affinities of a library of peptidic aminosugar conjugates (PAs) for ES7CA. For conjugates with highest affinities for ES7CA (NeoRH, NeoFH, and NeoYH), the lowest dose needed to induce mortality in C. albicans (minimum inhibitory concentration, MIC) was determined. PAs with the lowest MIC values were tested for cytotoxicity in HEK293T cells. Molecules with high affinity for ES7CA in vitro induce mortality in C. albicans but not in HEK293T cells. The results are consistent with the hypothesis that ESs represent useful targets for chemotherapeutics directed against eukaryotic pathogens.
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Affiliation(s)
- Lizzette M Gómez Ramos
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 315 Ferst Drive NW, Atlanta, Georgia 30332-0363, United States.,School of Chemical and Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, United States
| | - Natalya N Degtyareva
- NUBAD, LLC , 900 B West Farris Road, Greenville, South Carolina 29605, United States
| | - Nicholas A Kovacs
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 315 Ferst Drive NW, Atlanta, Georgia 30332-0363, United States
| | - Stefany Y Holguin
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, United States
| | - Liuwei Jiang
- Department of Chemistry, Clemson University , 436 Hunter Laboratories, Clemson, South Carolina 29634-0973, United States
| | - Anton S Petrov
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 315 Ferst Drive NW, Atlanta, Georgia 30332-0363, United States
| | - Marcin Biesiada
- RNA Structure and Function Laboratory, Institute of Bioorganic Chemistry, Polish Academy of Sciences , Poznan 61-704, Poland
| | - Michael Y Hu
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 315 Ferst Drive NW, Atlanta, Georgia 30332-0363, United States
| | - Katarzyna J Purzycka
- RNA Structure and Function Laboratory, Institute of Bioorganic Chemistry, Polish Academy of Sciences , Poznan 61-704, Poland
| | - Dev P Arya
- NUBAD, LLC , 900 B West Farris Road, Greenville, South Carolina 29605, United States.,Department of Chemistry, Clemson University , 436 Hunter Laboratories, Clemson, South Carolina 29634-0973, United States
| | - Loren Dean Williams
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 315 Ferst Drive NW, Atlanta, Georgia 30332-0363, United States
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11
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Granqvist L, Kraszewski A, Tähtinen V, Virta P. Synthesis of Aminoglycoside-2'-O-Methyl Oligoribonucleotide Fusions. Molecules 2017; 22:molecules22050760. [PMID: 28481305 PMCID: PMC6154110 DOI: 10.3390/molecules22050760] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/04/2017] [Accepted: 05/06/2017] [Indexed: 11/24/2022] Open
Abstract
Phosphoramidite building blocks of ribostamycin (3 and 4), that may be incorporated at any position of the oligonucleotide sequence, were synthesized. The building blocks, together with a previously described neomycin-modified solid support, were applied for the preparation of aminoglycoside-2′-O-methyl oligoribonucleotide fusions. The fusions were used to clamp a single strand DNA sequence (a purine-rich strand of c-Myc promoter 1) to form triple helical 2′-O-methyl RNA/DNA-hybrid constructs. The potential of the aminoglycoside moieties to stabilize the triple helical constructs were studied by UV-melting profile analysis.
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Affiliation(s)
- Lotta Granqvist
- Department of Chemistry, University of Turku, Vatselankatu 2, 20014 Turku, Finland.
| | - Andrzej Kraszewski
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02 097 Warsaw, Poland.
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Banacha 2c, 02 097 Warsaw, Poland.
| | - Ville Tähtinen
- Department of Chemistry, University of Turku, Vatselankatu 2, 20014 Turku, Finland.
| | - Pasi Virta
- Department of Chemistry, University of Turku, Vatselankatu 2, 20014 Turku, Finland.
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12
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Li Y, Syed J, Sugiyama H. RNA-DNA Triplex Formation by Long Noncoding RNAs. Cell Chem Biol 2016; 23:1325-1333. [DOI: 10.1016/j.chembiol.2016.09.011] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/29/2016] [Accepted: 09/26/2016] [Indexed: 01/06/2023]
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13
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Kumar S, Ranjan N, Kellish P, Gong C, Watkins D, Arya DP. Multivalency in the recognition and antagonism of a HIV TAR RNA-TAT assembly using an aminoglycoside benzimidazole scaffold. Org Biomol Chem 2016; 14:2052-6. [PMID: 26765486 DOI: 10.1039/c5ob02016f] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recognition of RNA by high-affinity binding small molecules is crucial for expanding existing approaches in RNA recognition, and for the development of novel RNA binding drugs. A novel neomycin dimer benzimidazole conjugate 5 (DPA 83) was synthesized by conjugating a neomycin-dimer with a benzimidazole alkyne using click chemistry to target multiple binding sites on HIV TAR RNA. Ligand 5 significantly enhances the thermal stability of HIV TAR RNA and interacts stoichiometrically with HIV TAR RNA with a low nanomolar affinity. 5 displayed enhanced binding compared to its individual building blocks including the neomycin dimer azide and benzimidazole alkyne. In essence, a high affinity multivalent ligand was designed and synthesized to target HIV TAR RNA.
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Affiliation(s)
- Sunil Kumar
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA.
| | - Nihar Ranjan
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA. and Nubad LLC, 900 B West Faris Road, Greenville, SC 29630, USA
| | - Patrick Kellish
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA.
| | - Changjun Gong
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA.
| | | | - Dev P Arya
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA.
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14
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Kumar S, Newby Spano M, Arya DP. Shape readout of AT-rich DNA by carbohydrates. Biopolymers 2016; 101:720-32. [PMID: 24281844 DOI: 10.1002/bip.22448] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/10/2013] [Accepted: 11/23/2013] [Indexed: 12/16/2022]
Abstract
Gene expression can be altered by small molecules that target DNA; sequence as well as shape selectivities are both extremely important for DNA recognition by intercalating and groove-binding ligands. We have characterized a carbohydrate scaffold (1) exhibiting DNA "shape readout" properties. Thermodynamic studies with 1 and model duplex DNAs demonstrate the molecule's high affinity and selectivity towards B* form (continuous AT-rich) DNA. Isothermal titration calorimetry (ITC), circular dichroism (CD) titration, ultraviolet (UV) thermal denaturation, and Differential Scanning Calorimetry were used to characterize the binding of 1 with a B* form AT-rich DNA duplex d[5'-G2 A6 T6 C2 -3']. The binding constant was determined using ITC at various temperatures, salt concentrations, and pH. ITC titrations were fit using a two-binding site model. The first binding event was shown to have a 1:1 binding stoichiometry and was predominantly entropy-driven with a binding constant of approximately 10(8) M(-1) . ITC-derived binding enthalpies were used to obtain the binding-induced change in heat capacity (ΔCp ) of -225 ± 19 cal/mol·K. The ionic strength dependence of the binding constant indicated a significant electrolytic contribution in ligand:DNA binding, with approximately four to five ion pairs involved in binding. Ligand 1 displayed a significantly higher affinity towards AT-tract DNA over sequences containing GC inserts, and binding experiments revealed the order of binding affinity for 1 with DNA duplexes: contiguous B* form AT-rich DNA (d[5'-G2 A6 T6 C2 -3']) >B form alternate AT-rich DNA (d[5'-G2 (AT)6 C2- 3']) > A form GC-rich DNA (d[5'-A2 G6 C6 T2 -3']), demonstrating the preference of ligand 1 for B* form DNA.
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Affiliation(s)
- Sunil Kumar
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC, 29634
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Kopaczynska M, Schulz A, Fraczkowska K, Kraszewski S, Podbielska H, Fuhrhop JH. Selective condensation of DNA by aminoglycoside antibiotics. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 45:287-99. [PMID: 26646261 PMCID: PMC4823326 DOI: 10.1007/s00249-015-1095-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 10/05/2015] [Accepted: 10/29/2015] [Indexed: 11/30/2022]
Abstract
The condensing effect of aminoglycoside antibiotics on the structure of double-stranded DNA was examined. The selective condensation of DNA by small molecules is an interesting approach in biotechnology. Here, we present the interaction between calf thymus DNA and three types of antibiotic molecules: tobramycin, kanamycin, and neomycin. Several techniques were applied to study this effect. Atomic force microscopy, transmission electron microscopy images, and nuclear magnetic resonance spectra showed that the interaction of tobramycin with double-stranded DNA caused the rod, toroid, and sphere formation and very strong condensation of DNA strands, which was not observed in the case of other aminoglycosides used in the experiment. Studies on the mechanisms by which small molecules interact with DNA are important in understanding their functioning in cells, in designing new and efficient drugs, or in minimizing their adverse side effects. Specific interactions between tobramycin and DNA double helix was modeled using molecular dynamics simulations. Simulation study shows the aminoglycoside specificity to bend DNA double helix, shedding light on the origins of toroid formation. This phenomenon may lighten the ototoxicity or nephrotoxicity issues, but also other adverse reactions of aminoglycoside antibiotics in the human body.
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Affiliation(s)
- M Kopaczynska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland.
| | - A Schulz
- Institut für Chemie and Biochemie, Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195, Berlin, Germany
| | - K Fraczkowska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - S Kraszewski
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - H Podbielska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Technology, Wybrzeże Wyspiańskiego 27, 50-370, Wrocław, Poland
| | - J H Fuhrhop
- Institut für Chemie and Biochemie, Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195, Berlin, Germany
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Kellish PC, Kumar S, Mack TS, Spano MN, Hennig M, Arya DP. Multivalent Amino Sugars to Recognize Different TAR RNA Conformations. MEDCHEMCOMM 2014; 5:1235-1246. [PMID: 27076899 PMCID: PMC4828046 DOI: 10.1039/c4md00165f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Neomycin dimers synthesized using "click chemistry" with varying functionality and length in the linker region have been shown to be effective in targeting the HIV-1 TAR RNA region of the HIV virus. TAR (Transactivation Response) RNA region, a 59 base pair stem loop structure located at the 5'-end of all nascent viral transcripts interacts with its target, a key regulatory protein, Tat, and necessitates the replication of HIV-1 virus. Ethidium bromide displacement and FRET competition assays have revealed nanomolar binding affinity between neomycin dimers and wildtype TAR RNA while in case of neomycin, only a weak binding was detected. Here, NMR and FID-based comparisons reveal an extended binding interface for neomycin dimers involving the upper stem of the TAR RNA thereby offering an explanation for increased affinities. To further explore the potential of these modified aminosugars we have extended binding studies to include four TAR RNA mutants that display conformational differences with minimal sequence variation. The differences in binding between neomycin and neomycin dimers is characterized with TAR RNA mutants that include mutations to the bulge region, hairpin region, and both the bulge and hairpin regions. Our results demonstrate the effect of these mutations on neomycin binding and our results show that linker functionalities between dimeric units of neomycin can distinguish between the conformational differences of mutant TAR RNA structures.
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Affiliation(s)
- Patrick C. Kellish
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Sunil Kumar
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Todd S. Mack
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 70 President St., Charleston, SC 29425
| | | | - Mirko Hennig
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 70 President St., Charleston, SC 29425
| | - Dev P. Arya
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
- NUBAD, LLC, 900B West Faris Rd., Greenville, SC 29605
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Willis B, Arya DP. Recognition of RNA duplex by a neomycin–Hoechst 33258 conjugate. Bioorg Med Chem 2014; 22:2327-32. [DOI: 10.1016/j.bmc.2014.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/27/2014] [Accepted: 02/06/2014] [Indexed: 01/01/2023]
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Yadav S, Mahato M, Pathak R, Jha D, Kumar B, Deka SR, Gautam HK, Sharma AK. Multifunctional self-assembled cationic peptide nanostructures efficiently carry plasmid DNA in vitro and exhibit antimicrobial activity with minimal toxicity. J Mater Chem B 2014; 2:4848-4861. [DOI: 10.1039/c4tb00657g] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An amphiphilic peptide–aminoglycoside (Pep–Neo) conjugate has been synthesized, self-assembled into nanostructures and evaluated for its multifunctional properties.
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Affiliation(s)
- Santosh Yadav
- Nucleic Acids Research Laboratory
- CSIR-Institute of Genomics and Integrative Biology
- Delhi – 110007, India
| | - Manohar Mahato
- Nucleic Acids Research Laboratory
- CSIR-Institute of Genomics and Integrative Biology
- Delhi – 110007, India
| | - Rajiv Pathak
- Microbial Biotechnology Laboratory
- CSIR-Institute of Genomics and Integrative Biology
- Delhi – 110020, India
| | - Diksha Jha
- Microbial Biotechnology Laboratory
- CSIR-Institute of Genomics and Integrative Biology
- Delhi – 110020, India
| | - Bipul Kumar
- Microbial Biotechnology Laboratory
- CSIR-Institute of Genomics and Integrative Biology
- Delhi – 110020, India
| | - Smriti Rekha Deka
- Nucleic Acids Research Laboratory
- CSIR-Institute of Genomics and Integrative Biology
- Delhi – 110007, India
| | - Hemant Kumar Gautam
- Microbial Biotechnology Laboratory
- CSIR-Institute of Genomics and Integrative Biology
- Delhi – 110020, India
| | - Ashwani Kumar Sharma
- Nucleic Acids Research Laboratory
- CSIR-Institute of Genomics and Integrative Biology
- Delhi – 110007, India
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Beck A, Vijayanathan V, Thomas T, Thomas TJ. Ionic microenvironmental effects on triplex DNA stabilization: cationic counterion effects on poly(dT)·poly(dA)·poly(dT). Biochimie 2013; 95:1310-8. [PMID: 23454377 DOI: 10.1016/j.biochi.2013.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/18/2013] [Indexed: 12/18/2022]
Abstract
The structure and conformation of nucleic acids are influenced by metal ions, polyamines, and the microenvironment. In poly(purine) · poly(pyrimidine) sequences, triplex DNA formation is facilitated by metal ions, polyamines and other ligands. We studied the effects of mono- and di-valent metal ions, and ammonium salts on the stability of triple- and double-stranded structures formed from poly(dA) and poly(dT) by measuring their respective melting temperatures. In the presence of metal ions, the absorbance versus temperature profile showed two transitions: Tm1 for triplex to duplex and single stranded DNA, and Tm2 for duplex DNA melting to single stranded DNA. Monovalent cations (Li(+), Na(+), K(+), Rb(+), Cs(+) and [Formula: see text] ) promoted triplex DNA at concentrations ≥150 mM. Tm1 varied from 49.8 °C in the presence of 150 mM Li(+) to 30.6 °C in the presence of 150 mM K(+). [Formula: see text] was very effective in stabilizing triplex DNA and its efficacy decreased with increasing substitution of the hydrogen atoms with methyl, ethyl, propyl and butyl groups. As in the case of monovalent cations, a concentration-dependent increase in Tm1 was observed with divalent ions and triplex DNA stabilization decreased in the order: Mg(2+) > Ca(2+) > Sr(2+) > Ba(2+). All positively charged cations increased the melting temperature of duplex DNA. Values of Δn (number of ions released) on triplex DNA melting were 0.46 ± 0.06 and 0.18 ± 0.02, respectively, for mono- and di-valent cations, as calculated from 1/Tm1 versus ln[M(+,2+)] plots. The corresponding values for duplex DNA were 0.25 ± 0.02 and 0.12 ± 0.02, respectively, for mono- and di-valent cations. Circular dichroism spectroscopic studies showed distinct conformational changes in triplex DNA stabilized by alkali metal and ammonium ions. Our results might be useful in developing triplex forming oligonucleotide based gene silencing techniques.
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Affiliation(s)
- Amanda Beck
- Department of Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, 125 Paterson St, New Brunswick, NJ 08903, USA
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Das I, Désiré J, Manvar D, Baussanne I, Pandey VN, Décout JL. A peptide nucleic acid-aminosugar conjugate targeting transactivation response element of HIV-1 RNA genome shows a high bioavailability in human cells and strongly inhibits tat-mediated transactivation of HIV-1 transcription. J Med Chem 2012; 55:6021-32. [PMID: 22698070 PMCID: PMC3400927 DOI: 10.1021/jm300253q] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The 6-aminoglucosamine ring of the aminoglycoside antibiotic neomycin B (ring II) was conjugated to a 16-mer peptide nucleic acid (PNA) targeting HIV-1 TAR RNA. For this purpose, we prepared the aminoglucosamine monomer 15 and attached it to the protected PNA prior to its cleavage from the solid support. We found that the resulting PNA-aminoglucosamine conjugate is stable under acidic conditions, efficiently taken up by the human cells and fairly distributed in both cytosol and nucleus without endosomal entrapment because cotreatment with endosome-disrupting agent had no effect on its cellular distribution. The conjugate displayed very high target specificity in vitro and strongly inhibited Tat mediated transactivation of HIV-1 LTR transcription in a cell culture system. The unique properties of this new class of PNA conjugate suggest it to be a potential candidate for therapeutic application.
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Affiliation(s)
- Indrajit Das
- Université de Grenoble I/CNRS, UMR 5063, Département de Pharmacochimie Moléculaire, ICMG FR 2607, 470 rue de la Chimie BP 53 F-38041 Grenoble, France
| | - Jérôme Désiré
- Université de Grenoble I/CNRS, UMR 5063, Département de Pharmacochimie Moléculaire, ICMG FR 2607, 470 rue de la Chimie BP 53 F-38041 Grenoble, France
| | - Dinesh Manvar
- Center for the Study of Emerging and Re-emerging Pathogens, UMDNJ-New Jersey Medical School, Department of Biochemistry and Molecular Biology, 185 South Orange Avenue, Newark, New Jersey 07103, USA
| | - Isabelle Baussanne
- Université de Grenoble I/CNRS, UMR 5063, Département de Pharmacochimie Moléculaire, ICMG FR 2607, 470 rue de la Chimie BP 53 F-38041 Grenoble, France
| | - Virendra N. Pandey
- Center for the Study of Emerging and Re-emerging Pathogens, UMDNJ-New Jersey Medical School, Department of Biochemistry and Molecular Biology, 185 South Orange Avenue, Newark, New Jersey 07103, USA
| | - Jean-Luc Décout
- Université de Grenoble I/CNRS, UMR 5063, Département de Pharmacochimie Moléculaire, ICMG FR 2607, 470 rue de la Chimie BP 53 F-38041 Grenoble, France
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Charles I, Davis E, Arya DP. Efficient stabilization of phosphodiester (PO), phosphorothioate (PS), and 2'-O-methoxy (2'-OMe) DNA·RNA hybrid duplexes by amino sugars. Biochemistry 2012; 51:5496-505. [PMID: 22639785 DOI: 10.1021/bi3004507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Antisense strategies that target DNA·RNA hybrid structures offer potential for the development of new therapeutic drugs. The α-sarcin loop region of the 23S [corrected] rRNA domain has been shown to be a high value target for such strategies. Herein, aminoglycoside interaction with three RNA·DNA α-sarcin targeted duplexes (rR·dY, rR·S-dY, and rR·2'OMe-rY) have been investigated to determine the overall effect of aminoglycoside interaction on the stability, affinity, and conformation of these hybrid duplexes. To this end, UV thermal denaturation, circular dichroism spectroscopy, fluorescence intercalator displacement, and ITC as well as DSC calorimetry experiments were carried out. The results suggest the following. (1) Of all the aminoglycosides studied, neomycin confers the highest thermal stability on all three hybrid duplexes studied. (2) There is no appreciable difference in aminoglycoside-induced thermal stability between the unmodified rR·dY and phophorothioate modified rR·S-dY duplexes. (3) The rR·2'OMe-rY duplexes thermal stability is slightly less than the other two hybrids. (4) In all three duplexes, aminoglycoside-induced thermal stability decreased as the number of amino groups decreased. (5) CD scans revealed similar spectra for the rR·dY and rR·S-dY duplexes as well as a more pronounced A-form signal for the rR·2'OMe-rY duplex. (6) FID assays paralleled the CD results, yielding similar affinity values between the rR·dY and rR·S-dY duplexes and higher affinities with the rR·2'OMe-rY duplex. (7) The overall affinity trend between aminoglycosides and the three duplexes was determined to be neomycin > paromomycin > neamine > ribostamycin. (8) ITC K(a) values revealed similar binding constants for the rR·dY and rR·S-dY duplexes with rR·dY having a K(1) of (1.03 ± 0.58) × 10(7) M(-1) and K(2) of (1.13 ± 0.07) × 10(5) M(-1) while rR·S-dY produced a K(1) of (1.17 ± 0.54) × 10(7) M(-1) and K(2) of (1.27 ± 0.69) × 10(5) M(-1). (8) The rR·2'OMe-rY produced a slightly higher binding constant values with a K(1) of (1.25 ± 0.24) × 10(7) M(-1) and K(2) of (3.62 ± 0.18) × 10(5) M(-1). (9) The ΔT(m)-derived K(Tm) of 3.81 × 10(7) M(-1) for rR·S-dY was in relative agreement with the corresponding K(1) of 1.17 × 10(7) M(-1) derived constant from the fitted ITC. These results illustrate that the increased DNA·RNA hybrid duplex stability in the presence of aminoglycosides can help extend the roles of aminoglycosides in designing modified ODNs for targeting RNA.
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Affiliation(s)
- I Charles
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, South Carolina 29634, United States
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22
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Kumar S, Kellish P, Robinson WE, Wang D, Appella DH, Arya DP. Click dimers to target HIV TAR RNA conformation. Biochemistry 2012; 51:2331-47. [PMID: 22339203 DOI: 10.1021/bi201657k] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of neomycin dimers have been synthesized using "click chemistry" with varying functionality and length in the linker region to target the human immunodeficiency virus type 1 (HIV-1) TAR RNA region of the HIV virus. The TAR (Trans-Activation Responsive) RNA region, a 59 bp stem-loop structure located at the 5'-end of all nascent viral transcripts, interacts with its target, a key regulatory protein, Tat, and necessitates the replication of HIV-1. Neomycin, an aminosugar, has been shown to exhibit multiple binding sites on TAR RNA. This observation prompted us to design and synthesize a library of triazole-linked neomycin dimers using click chemistry. The binding between neomycin dimers and TAR RNA was characterized using spectroscopic techniques, including FID (fluorescent intercalator displacement), a FRET (fluorescence resonance energy transfer) competitive assay, circular dichroism (CD), and UV thermal denaturation. UV thermal denaturation studies demonstrate that binding of neomycin dimers increases the melting temperature (T(m)) of the HIV TAR RNA up to 10 °C. Ethidium bromide displacement (FID) and a FRET competition assay revealed nanomolar binding affinity between neomycin dimers and HIV TAR RNA, while in case of neomycin, only weak binding was detected. More importantly, most of the dimers exhibited lower IC(50) values toward HIV TAR RNA, when compared to the fluorescent Tat peptide, and show increased selectivity over mutant TAR RNA. Cytopathic effects investigated using MT-2 cells indicate a number of the dimers with high affinity toward TAR show promising anti-HIV activity.
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Affiliation(s)
- Sunil Kumar
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
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Mazurek B, Lou X, Olze H, Haupt H, Szczepek AJ. In vitro protection of auditory hair cells by salicylate from the gentamicin-induced but not neomycin-induced cell loss. Neurosci Lett 2011; 506:107-10. [PMID: 22075224 DOI: 10.1016/j.neulet.2011.10.060] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 09/16/2011] [Accepted: 10/25/2011] [Indexed: 11/26/2022]
Abstract
Salicylate has been shown to protect animals and people from the gentamicin-induced hearing loss. The objective of our study was to determine if salicylate is otoprotective in vitro. In this fashion, we wanted to validate the use of explant culture system for future studies on the ototoxicity prevention. In addition, we wanted to find out if salicylate protects from the ototoxicity of other aminoglycosides. As a model, we used the membranous cochlear tissues containing the organ of Corti, spiral limbus and spiral ganglion neurons dissected from the cochleas of p3-p5 Wistar pups. The explants were divided into apical, medial and basal parts and cultured in presence or absence of 100μM gentamicin, 100μM neomycin and 5mM salicylate. Following the tissue fixation and staining with phalloidin-TRITC, the number of inner and outer hair cells (IHCs, OHCs) was scored under the fluorescent microscope. Presence of 5mM salicylate in explants cultures exposed to 100μM gentamicin significantly reduced the loss of IHCs and OHCs, as compared to explants exposed to gentamicin alone. In contrast, neomycin-induced auditory hair cell loss remained unaffected by the presence of salicylate. Our results corroborate earlier in vivo findings and validate the use of cochlear explants for future studies on ototoxicity and its prevention. Moreover, the inability of salicylate to prevent neomycin-induced ototoxicity implies possible differences between the mechanisms of auditory hair cell loss induced by gentamicin and neomycin.
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Affiliation(s)
- Birgit Mazurek
- Molecular Biology Research Laboratory, Department of Otorhinolaryngology, Charité - Universitätsmedizin Berlin, Campus Charité Mitte, Charitéplatz 1, 10117 Berlin, Germany.
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Xi H, Davis E, Ranjan N, Xue L, Hyde-Volpe D, Arya DP. Thermodynamics of nucleic acid "shape readout" by an aminosugar. Biochemistry 2011; 50:9088-113. [PMID: 21863895 PMCID: PMC3673541 DOI: 10.1021/bi201077h] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Recognition of nucleic acids is important for our understanding of nucleic acid structure as well as for our understanding of nucleic acid-protein interactions. In addition to the direct readout mechanisms of nucleic acids such as H-bonding, shape recognition of nucleic acids is being increasingly recognized as playing an equally important role in DNA recognition. Competition dialysis, UV, flourescent intercalator displacement (FID), computational docking, and calorimetry studies were conducted to study the interaction of neomycin with a variety of nucleic acid conformations (shapes). At pH 5.5, the results suggest the following. (1) Neomycin binds three RNA structures [16S A site rRNA, poly(rA)·poly(rA), and poly(rA)·poly(rU)] with high affinities (K(a) ~ 10(7) M(-1)). (2) The binding of neomycin to A-form GC-rich oligomer d(A(2)G(15)C(15)T(2))(2) has an affinity comparable to those of RNA structures. (3) The binding of neomycin to DNA·RNA hybrids shows a 3-fold variance that can be attributed to their structural differences [for poly(dA)·poly(rU), K(a) = 9.4 × 10(6) M(-1), and for poly(rA)·poly(dT), K(a) = 3.1 × 10(6) M(-1)]. (4) The interaction of neomycin with DNA triplex poly(dA)·2poly(dT) yields a binding affinity (K(a)) of 2.4 × 10(5) M(-1). (5) Poly(dA-dT)(2) shows the lowest association constant for all nucleic acids studied (K(a) < 10(5)). (6) Neomycin binds to G-quadruplexes with K(a) values of ~10(4)-10(5) M(-1). (7) Computational studies show that the decrease in major groove width in the B to A transition correlates with increasing neomycin affinity. Neomycin's affinity for various nucleic acid structures can be ranked as follows: RNAs and GC-rich d(A(2)G(15)C(15)T(2))(2) structures > poly(dA)·poly(rU) > poly(rA)·poly(dT) > T·A-T triplex, G-quadruplex, B-form AT-rich, or GC-rich DNA sequences. The results illustrate the first example of a small molecule-based "shape readout" of different nucleic acid conformations.
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Affiliation(s)
- Hongjuan Xi
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina, 29634
| | - Erik Davis
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina, 29634
| | - Nihar Ranjan
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina, 29634
| | - Liang Xue
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina, 29634
| | - David Hyde-Volpe
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina, 29634
| | - Dev P. Arya
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina, 29634
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Kiviniemi A, Virta P. Synthesis of aminoglycoside-3'-conjugates of 2'-O-methyl oligoribonucleotides and their invasion to a 19F labeled HIV-1 TAR model. Bioconjug Chem 2011; 22:1559-66. [PMID: 21688836 DOI: 10.1021/bc200101r] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The potential of aminoglycosides to induce RNA-invasion has been demonstrated. For this purpose, aminoglycoside-3'-conjugates of 2'-O-methyl oligoribonucleotides have been synthesized entirely on a solid phase. The synthesis includes an automated oligonucleotide chain elongation to solid-supported neomycin, ribostamycin, and methyl neobiosamine, and a two-step deprotection/release of the solid-supported conjugate, which allows exploitation of a simple protecting group scheme. Conjugates have been targeted to a (19)F labeled HIV-1 TAR RNA model (Trans Activation Response element of HIV), which allows monitoring of the invasion by (19)F NMR spectroscopy. A remarkably enhanced invasion, compared to that resulting from the corresponding unmodified 2'-O-methyl oligoribonucleotide (5'-CAGGCUCA-3'), has been obtained by the neomycin conjugate. The increased affinity results from a cooperative binding of the neomycin moiety and hybridization, though the invasion may also follow a mechanism, in which the first molar equivalent of the conjugate induces hybridization of the second.
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Affiliation(s)
- Anu Kiviniemi
- Department of Chemistry, University of Turku, FIN-20014 Turku, Finland
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27
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Kumar S, Xue L, Arya DP. Neomycin-neomycin dimer: an all-carbohydrate scaffold with high affinity for AT-rich DNA duplexes. J Am Chem Soc 2011; 133:7361-75. [PMID: 21524066 PMCID: PMC3641821 DOI: 10.1021/ja108118v] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A dimeric neomycin-neomycin conjugate 3 with a flexible linker, 2,2'-(ethylenedioxy)bis(ethylamine), has been synthesized and characterized. Dimer 3 can selectively bind to AT-rich DNA duplexes with high affinity. Biophysical studies have been performed between 3 and different nucleic acids with varying base composition and conformation by using ITC (isothermal calorimetry), CD (circular dichroism), FID (fluorescent intercalator displacement), and UV (ultraviolet) thermal denaturation experiments. A few conclusions can be drawn from this study: (1) FID assay with 3 and polynucleotides demonstrates the preference of 3 toward AT-rich sequences over GC-rich sequences. (2) FID assay and UV thermal denaturation experiments show that 3 has a higher affinity for the poly(dA)·poly(dT) DNA duplex than for the poly(dA)·2poly(dT) DNA triplex. Contrary to neomycin, 3 destabilizes poly(dA)·2poly(dT) triplex but stabilizes poly(dA)·poly(dT) duplex, suggesting the major groove as the binding site. (3) UV thermal denaturation studies and ITC experiments show that 3 stabilizes continuous AT-tract DNA better than DNA duplexes with alternating AT bases. (4) CD and FID titration studies show a DNA binding site size of 10-12 base pairs/drug, depending upon the structure/sequence of the duplex for AT-rich DNA duplexes. (5) FID and ITC titration between 3 and an intramolecular DNA duplex [d(5'-A(12)-x-T(12)-3'), x = hexaethylene glycol linker] results in a binding stoichiometry of 1:1 with a binding constant ∼10(8) M(-1) at 100 mM KCl. (6) FID assay using 3 and 512 hairpin DNA sequences that vary in their AT base content and placement also show a higher binding selectivity of 3 toward continuous AT-rich than toward DNA duplexes with alternate AT base pairs. (7) Salt-dependent studies indicate the formation of three ion pairs during binding of the DNA duplex d[5'-A(12)-x-T(12)-3'] and 3. (8) ITC-derived binding constants between 3 and DNA duplexes have the following order: AT continuous, d[5'-G(3)A(5)T(5)C(3)-3'] > AT alternate, d[5'-G(3)(AT)(5)C(3)-3'] > GC-rich d[5'-A(3)G(5)C(5)T(3)-3']. (9) 3 binds to the AT-tract-containing DNA duplex (B* DNA, d[5'-G(3)A(5)T(5)C(3)-3']) with 1 order of magnitude higher affinity than to a DNA duplex with alternating AT base pairs (B DNA, d[5'-G(3)(AT)(5)C(3)-3']) and with almost 3 orders of magnitude higher affinity than a GC-rich DNA (A-form, d[5'-A(3)G(5)C(5)T(3)-3']).
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Affiliation(s)
- Sunil Kumar
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634
| | | | - Dev P. Arya
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634
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Xue L, Ranjan N, Arya DP. Synthesis and spectroscopic studies of the aminoglycoside (neomycin)--perylene conjugate binding to human telomeric DNA. Biochemistry 2011; 50:2838-49. [PMID: 21329360 DOI: 10.1021/bi1017304] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Synthesis of a novel perylene-neomycin conjugate (3) and the properties of its binding to human telomeric G-quadruplex DNA, 5'-d[AG3(T2AG3)3] (4), are reported. Various spectroscopic techniques were employed to characterize the binding of conjugate 3 to 4. A competition dialysis assay revealed that 3 preferentially binds to 4, in the presence of other nucleic acids, including DNA, RNA, DNA-RNA hybrids, and other higher-order structures (single strands, duplexes, triplexes, other G-quadruplexes, and the i-motif). UV thermal denaturation studies showed that thermal stabilization of 4 increases as a function of the increasing concentration of 3. The fluorescence intercalator displacement (FID) assay displayed a significantly tighter binding of 3 with 4 as compared to its parent constituents [220-fold stronger than neomycin (1) and 4.5-fold stronger than perylene diamine (2), respectively]. The binding of 3 with 4 resulted in pronounced changes in the molar ellipticity of the DNA absorption region as confirmed by circular dichroism. The UV-vis absorption studies of the binding of 3 to 4 resulted in a red shift in the spectrum of 3 as well as a marked hypochromic change in the perylene absorption region, suggesting that the ligand-quadruplex interaction involves stacking of the perylene moiety. Docking studies suggest that the perylene moiety serves as a bridge that end stacks on 4, making contacts with two thymine bases in the loop, while the two neomycin moieties branch into the grooves of 4.
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Affiliation(s)
- Liang Xue
- Laboratories of Medicinal Chemistry, Clemson University, Clemson, South Carolina 29634, United States
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29
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Abstract
A DNA duplex can be recognized sequence-specifically in the major groove by an oligodeoxynucleotide (ODN). The resulting structure is a DNA triple helix, or triplex. The scientific community has invested significant research capital in the study of DNA triplexes because of their robust potential for providing new applications, including molecular biology tools and therapeutic agents. The triplex structures have inherent instabilities, however, and the recognition of DNA triplexes by small molecules has been attempted as a means of strengthening the three-stranded complex. Over the decades, the majority of work in the field has focused on heterocycles that intercalate between the triplex bases. In this Account, we present an alternate approach to recognition and stabilization of DNA triplexes. We show that groove recognition of nucleic acid triple helices can be achieved with aminosugars. Among these aminosugars, neomycin is the most effective aminoglycoside (groove binder) for stabilizing a DNA triple helix. It stabilizes both the TAT triplex and mixed-base DNA triplexes better than known DNA minor groove binders (which usually destabilize the triplex) and polyamines. Neomycin selectively stabilizes the triplex (TAT and mixed base) without any effect on the DNA duplex. The selectivity of neomycin likely originates from its potential and shape complementarity to the triplex Watson-Hoogsteen groove, making it the first molecule that selectively recognizes a triplex groove over a duplex groove. The groove recognition of aminoglycosides is not limited to DNA triplexes, but also extends to RNA and hybrid triple helical structures. Intercalator-neomycin conjugates are shown to simultaneously probe the base stacking and groove surface in the DNA triplex. Calorimetric and spectrosocopic studies allow the quantification of the effect of surface area of the intercalating moiety on binding to the triplex. These studies outline a novel approach to the recognition of DNA triplexes that incorporates the use of noncompeting binding sites. These principles of dual recognition should be applicable to the design of ligands that can bind any given nucleic acid target with nanomolar affinities and with high selectivity.
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Ranjan N, Andreasen KF, Kumar S, Hyde-Volpe D, Arya DP. Aminoglycoside binding to Oxytricha nova telomeric DNA. Biochemistry 2010; 49:9891-903. [PMID: 20886815 DOI: 10.1021/bi101517e] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Telomeric DNA sequences have been at the center stage of drug design for cancer treatment in recent years. The ability of these DNA structures to form four-stranded nucleic acid structures, called G-quadruplexes, has been perceived as target for inhibiting telomerase activity vital for the longevity of cancer cells. Being highly diverse in structural forms, these G-quadruplexes are subjects of detailed studies of ligand-DNA interactions of different classes, which will pave the way for logical design of more potent ligands in future. The binding of aminoglycosides was investigated with Oxytricha nova quadruplex forming DNA sequence (GGGGTTTTGGGG)(2). Isothermal titration calorimetry (ITC) determined ligand to quadruplex binding ratio shows 1:1 neomycin:quadruplex binding with association constants (K(a)) ∼ 10(5) M(-1) while paromomycin was found to have a 2-fold weaker affinity than neomycin. The CD titration experiments with neomycin resulted in minimal changes in the CD signal. FID assays, performed to determine the minimum concentration required to displace half of the fluorescent probe bound, showed neomycin as the best of the all aminoglycosides studied for quadruplex binding. Initial NMR footprint suggests that ligand-DNA interactions occur in the wide groove of the quadruplex. Computational docking studies also indicate that aminoglycosides bind in the wide groove of the quadruplex.
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Affiliation(s)
- Nihar Ranjan
- Laboratories of Medicinal Chemistry, Clemson University, Clemson, South Carolina 29634, United States
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31
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Chen C, Song G, Yang X, Ren J, Qu X. A gold nanoparticle-based strategy for label-free and colorimetric screening of DNA triplex binders. Biochimie 2010; 92:1416-21. [DOI: 10.1016/j.biochi.2010.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Accepted: 07/05/2010] [Indexed: 11/28/2022]
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Xue L, Xi H, Kumar S, Gray D, Davis E, Hamilton P, Skriba M, Arya DP. Probing the recognition surface of a DNA triplex: binding studies with intercalator-neomycin conjugates. Biochemistry 2010; 49:5540-52. [PMID: 20499878 DOI: 10.1021/bi100071j] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Thermodynamic studies on the interactions between intercalator-neomycin conjugates and a DNA polynucleotide triplex [poly(dA).2poly(dT)] were conducted. To draw a complete picture of such interactions, naphthalene diimide-neomycin (3) and anthraquinone-neomycin (4) conjugates were synthesized and used together with two other analogues, previously synthesized pyrene-neomycin (1) and BQQ-neomycin (2) conjugates, in our investigations. A combination of experiments, including UV denaturation, circular dichroism (CD) titration, differential scanning calorimetry (DSC), and isothermal titration calorimetry (ITC), revealed that all four conjugates (1-4) stabilized poly(dA).2poly(dT) much more than its parent compound, neomycin. UV melting experiments clearly showed that the temperature (T(m3-->2)) at which poly(dA).2poly(dT) dissociated into poly(dA).poly(dT) and poly(dT) increased dramatically (>12 degrees C) in the presence of intercalator-neomycin conjugates (1-4) even at a very low concentration (2 muM). In contrast to intercalator-neomycin conjugates, the increment of T(m3-->2) of poly(dA).2poly(dT) induced by neomycin was negligible under the same conditions. The binding preference of intercalator-neomycin conjugates (1-4) to poly(dA).2poly(dT) was also confirmed by competition dialysis and a fluorescent intercalator displacement assay. Circular dichroism titration studies revealed that compounds 1-4 had slightly larger binding site size ( approximately 7-7.5) with poly(dA).2poly(dT) as compared to neomycin ( approximately 6.5). The thermodynamic parameters of these intercalator-neomycin conjugates with poly(dA).2poly(dT) were derived from an integrated van't Hoff equation using the T(m3-->2) values, the binding site size numbers, and other parameters obtained from DSC and ITC. The binding affinity of all tested ligands with poly(dA).2poly(dT) increased in the following order: neomycin < 1 < 3 < 4 < 2. Among them, the binding constant [(2.7 +/- 0.3) x 10(8) M(-1)] of 2 with poly(dA).2poly(dT) was the highest, almost 1000-fold greater than that of neomycin. The binding of compounds 1-4 with poly(dA).2poly(dT) was mostly enthalpy-driven and gave negative DeltaC(p) values. The results described here suggest that the binding affinity of intercalator-neomycin conjugates for poly(dA).2poly(dT) increases as a function of the surface area of the intercalator moiety.
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Affiliation(s)
- Liang Xue
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA
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Jain AK, Bhattacharya S. Groove Binding Ligands for the Interaction with Parallel-Stranded ps-Duplex DNA and Triplex DNA. Bioconjug Chem 2010; 21:1389-403. [DOI: 10.1021/bc900247s] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Akash K. Jain
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India, Chemical Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560012, India
| | - Santanu Bhattacharya
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India, Chemical Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560012, India
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Xi H, Kumar S, Dosen-Micovic L, Arya DP. Calorimetric and spectroscopic studies of aminoglycoside binding to AT-rich DNA triple helices. Biochimie 2010; 92:514-29. [PMID: 20167243 PMCID: PMC3977217 DOI: 10.1016/j.biochi.2010.02.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2009] [Accepted: 02/08/2010] [Indexed: 11/21/2022]
Abstract
Calorimetric and fluorescence techniques were used to characterize the binding of aminoglycosides-neomycin, paromomycin, and ribostamycin, with 5'-dA(12)-x-dT(12)-x-dT(12)-3' intramolecular DNA triplex (x = hexaethylene glycol) and poly(dA).2poly(dT) triplex. Our results demonstrate the following features: (1) UV thermal analysis reveals that the T(m) for triplex decreases with increasing pH value in the presence of neomycin, while the T(m) for the duplex remains unchanged. (2) The binding affinity of neomycin decreases with increased pH, although there is an increase in observed binding enthalpy. (3) ITC studies conducted in two buffers (sodium cacodylate and MOPS) yield the number of protonated drug amino groups (Deltan) as 0.29 and 0.40 for neomycin and paromomycin interaction with 5'-dA(12)-x-dT(12)-x-dT(12)-3', respectively. (4) The specific heat capacity change (DeltaC(p)) determined by ITC studies is negative, with more negative values at lower salt concentrations. From 100 mM to 250 mM KCl, the DeltaC(p) ranges from -402 to -60 cal/(mol K) for neomycin. At pH 5.5, a more positive DeltaC(p) is observed, with a value of -98 cal/(mol K) at 100 mM KCl. DeltaC(p) is not significantly affected by ionic strength. (5) Salt dependence studies reveal that there are at least three amino groups of neomycin participating in the electrostatic interactions with the triplex. (6) FID studies using thiazole orange were used to derive the AC(50) (aminoglycoside concentration needed to displace 50% of the dye from the triplex) values. Neomycin shows a seven fold higher affinity than paromomycin and eleven fold higher affinity than ribostamycin at pH 6.8. (7) Modeling studies, consistent with UV and ITC results, show the importance of an additional positive charge in triplex recognition by neomycin. The modeling and thermodynamic studies indicate that neomycin binding to the DNA triplex depends upon significant contributions from charge as well as shape complementarity of the drug to the DNA triplex Watson-Hoogsteen groove.
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Affiliation(s)
- Hongjuan Xi
- Contribution from the Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
| | - Sunil Kumar
- Contribution from the Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
| | - Ljiljana Dosen-Micovic
- Contribution from the Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
| | - Dev P. Arya
- Contribution from the Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
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35
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Willis B, Arya DP. Triple recognition of B-DNA by a neomycin-Hoechst 33258-pyrene conjugate. Biochemistry 2010; 49:452-69. [PMID: 20000367 DOI: 10.1021/bi9016796] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recent developments have indicated that aminoglycoside binding is not limited to RNA, but to nucleic acids that, like RNA, adopt conformations similar to its A-form. We further sought to expand the utility of aminoglycoside binding to B-DNA structures by conjugating neomycin, an aminoglycoside antibiotic, with the B-DNA minor groove binding ligand Hoechst 33258. Envisioning a dual groove binding mode, we have extended the potential recognition process to include a third, intercalative moiety. Similar conjugates, which vary in the number of binding moieties but maintain identical linkages to allow direct comparisons to be made, have also been prepared. We report herein novel neomycin- and Hoechst 33258-based conjugates developed in our laboratories for exploring the recognition potential with B-DNA. Spectroscopic studies such as UV melting, differential scanning calorimetry, isothermal fluorescence titrations, and circular dichroism together illustrate the triple recognition of the novel conjugate containing neomycin, Hoechst 33258, and pyrene. This study represents the first example of DNA molecular recognition capable of minor versus major groove recognition in conjunction with intercalation.
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Affiliation(s)
- Bert Willis
- Laboratories of Medicinal Chemistry, Clemson University, Clemson, South Carolina 29634, USA
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36
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Xi H, Gray D, Kumar S, Arya DP. Molecular recognition of single-stranded RNA: neomycin binding to poly(A). FEBS Lett 2009; 583:2269-75. [PMID: 19520078 DOI: 10.1016/j.febslet.2009.06.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 06/01/2009] [Accepted: 06/03/2009] [Indexed: 02/04/2023]
Abstract
Poly(A) is a relevant sequence in cell biology due to its importance in mRNA stability and translation initiation. Neomycin is an aminoglycoside antibiotic that is well known for its ability to target various nucleic acid structures. Here it is reported that neomycin is capable of binding tightly to a single-stranded oligonucleotide (A(30)) with a K(d) in the micromolar range. CD melting experiments support complex formation and indicate a melting temperature of 47 degrees C. The poly(A) duplex, which melts at 44 degrees C (pH 5.5), was observed to melt at 61 degrees C in the presence of neomycin, suggesting a strong stabilization of the duplex by the neomycin.
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Affiliation(s)
- Hongjuan Xi
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA
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37
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Affiliation(s)
- Bert Willis
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA
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38
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Napoli S, Carbone GM, Catapano CV, Shaw N, Arya DP. Neomycin improves cationic lipid-mediated transfection of DNA in human cells. Bioorg Med Chem Lett 2005; 15:3467-9. [PMID: 15950473 DOI: 10.1016/j.bmcl.2005.04.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 04/20/2005] [Accepted: 04/21/2005] [Indexed: 11/18/2022]
Abstract
Delivery of oligonucleotides has been a major impediment in the development of nucleic acid based drugs. In this report, we show that neomycin, an aminoglycoside antibiotic, when combined with a cationic lipid preparation such as DOTAP, enhances transfection efficiency of both reporter plasmids and oligonucleotides and results in a significant increase in transgene expression. The results described here open a new lead in ongoing efforts for oligonucleotide delivery.
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Affiliation(s)
- Sara Napoli
- Laboratory of Experimental Oncology, Oncology Institute of Southern Switzerland (IOSI) Via Vela 6, 6500 Bellinzona, Switzerland
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39
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Arya DP, Coffee RL, Xue L. From triplex to B-form duplex stabilization: reversal of target selectivity by aminoglycoside dimers. Bioorg Med Chem Lett 2005; 14:4643-6. [PMID: 15324880 DOI: 10.1016/j.bmcl.2004.07.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 07/01/2004] [Accepted: 07/01/2004] [Indexed: 11/30/2022]
Abstract
Aminoglycosides have been shown to target A-form nucleic acids. Our work has previously shown that neomycin (and other aminoglycosides) bind and stabilize DNA/RNA triplexes and other A-form nucleic acids. We report herein the unexpected B-form duplex stabilization shown by aminoglycoside dimers (neomycin-neomycin and neomycin-tobramycin). The dimers are highly selective for AT rich duplexes and show high affinity (K(a) approximately 10(8)M(-1)) as determined by isothermal titration calorimetry.
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Affiliation(s)
- Dev P Arya
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
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40
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41
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Tok JBH, Bi L. A comparative binding study of BIV Tat peptide against its TAR RNA duplex, RNA–DNA heteroduplex and DNA duplex. Bioorg Med Chem Lett 2005; 15:129-33. [PMID: 15582425 DOI: 10.1016/j.bmcl.2004.10.030] [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] [Received: 08/31/2004] [Revised: 10/07/2004] [Accepted: 10/07/2004] [Indexed: 10/26/2022]
Abstract
Association between RNA and DNA strands to form RNA-DNA heteroduplex is important in many biological processes such as transcription, DNA replication and reverse transcription. Herein, binding affinities of a 17-mer BIV Tat peptide is compared with TAR DNA duplex, TAR RNA-DNA heteroduplex and TAR RNA duplex. It was observed that binding affinities of Tat peptide is comparable against DNA-RNA heteroduplex and RNA duplex, whereas DNA duplex binding is decidedly poor.
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Affiliation(s)
- Jeffrey B-H Tok
- Department of Chemistry, York College and Graduate Center, The City University of New York (CUNY), 94-20 Guy R. Brewer Blvd., Jamaica, NY 11451, USA.
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42
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Abstract
Development of aminoglycoside-nucleic acid conjugates is presented. Synthesis of a DNA dimer covalently linked to kanamycin and neomycin isothiocyanates has been carried out. The development of such conjugates will help couple the sequence specificity of nucleic acids to the electrostatic/shape complementarity of aminoglycoside antibiotics in binding nucleic acid targets.
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Affiliation(s)
- I Charles
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
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43
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Affiliation(s)
- D P Arya
- Laboratory of Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA.
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44
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Constantinou-Kokotou T, Karikas G, Kokotos G. Study of aminoglycoside-nucleic acid interactions by an HPLC method. Bioorg Med Chem Lett 2001; 11:1015-8. [PMID: 11327578 DOI: 10.1016/s0960-894x(01)00115-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The interactions of a number of aminoglycoside antibiotics with tRNA and DNA were studied by an HPLC method. based on tRNA and DNA peak size exclusion. Among the compounds studied (deoxystreptamine, neamine, neomycin B, kanamycin A, gentamicin A, netilmicin, streptomycin, and the synthetic neamine analogue BKN3), neomycin B and the synthetic analogue of neamine were proved to be the most potent binders.
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