1
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El-Sayed SM, Ahmed SA, Gulia K, Lenhard JR, Hassan AHE, Farahat AA. Small Molecules Incorporating Privileged Amidine Moiety as Potential Hits Combating Antibiotic-Resistant Bacteria. Pharmaceuticals (Basel) 2023; 16:1040. [PMID: 37513951 PMCID: PMC10384254 DOI: 10.3390/ph16071040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/07/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
The continuing need for the discovery of potent antibacterial agents against antibiotic-resistant pathogens is the driving force for many researchers to design and develop such agents. Herein, we report the design, synthesis, and biological evaluation of amidine derivatives as new antibacterial agents. Compound 13d was the most active in this study against a wide range of antibiotic-resistant, and susceptible, Gram-positive, and Gram-negative bacterial strains. Time-kill assay experiments indicated that compound 13d was an effective bactericidal compound against the tested organisms at the log-phase of bacterial growth. Docking simulations were performed to assess in silico its mode of action regarding UPPS, KARI, and DNA as potential bacterial targets. Results unveiled the importance of structural features of compound 13d in its biological activity including central thiophene ring equipped with left and right pyrrolo[2,3-b]pyridine and phenyl moieties and two terminal amidines cyclized into 4,5-dihydro-1H-imidazol-2-yl functionalities. Collectively, compound 13d represents a possible hit for future development of potent antibacterial agents.
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Affiliation(s)
- Selwan M El-Sayed
- Department of Medicinal Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
- Pharmaceutical Chemistry Department, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa 35712, Egypt
| | - Samar A Ahmed
- Department of Clinical and Administrative Sciences, College of Pharmacy, California Northstate University, Elk Grove, CA 95757, USA
| | - Kanika Gulia
- Master of Pharmaceutical Sciences Program, California Northstate University, 9700 W Taron Dr., Elk Grove, CA 95757, USA
| | - Justin R Lenhard
- Department of Clinical and Administrative Sciences, College of Pharmacy, California Northstate University, Elk Grove, CA 95757, USA
| | - Ahmed H E Hassan
- Department of Medicinal Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
- Medicinal Chemistry Laboratory, College of Pharmacy, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Abdelbasset A Farahat
- Master of Pharmaceutical Sciences Program, California Northstate University, 9700 W Taron Dr., Elk Grove, CA 95757, USA
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
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2
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Farahat AA, Kumar A, Wenzler T, Brun R, Paul A, Guo P, Wilson WD, Boykin DW. Investigation of the effect of structure modification of furamidine on the DNA minor groove binding and antiprotozoal activity. Eur J Med Chem 2023; 252:115287. [PMID: 36958267 PMCID: PMC10127280 DOI: 10.1016/j.ejmech.2023.115287] [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: 02/14/2023] [Revised: 03/05/2023] [Accepted: 03/14/2023] [Indexed: 03/25/2023]
Abstract
New analogs of the antiprotozoal agent Furamidine were prepared utilizing Stille coupling reactions and amidation of the bisnitrile intermediate using lithium bis-trimethylsilylamide. Both the phenyl groups and the furan moiety of furamidine were replaced by heterocycles including thiophene, selenophene, indole or benzimidazole. Based upon the ΔTm and the CD results, the new compounds showed strong binding to the DNA minor groove. The new analogues are also more active both in vitro and in vivo than furamidine. Compounds 7a, 7b, and 7f showed the highest activity in vivo by curing 75% of animals, and this merits further evaluation.
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Affiliation(s)
- Abdelbasset A Farahat
- Masters of Pharmaceutical Sciences Program, California Northstate University, Elk Grove, CA, 95757, USA; Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt.
| | - Arvind Kumar
- Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA
| | - Tanja Wenzler
- Swiss Tropical and Public Health Institute, Basel, 4002, Switzerland; University of Basel, Basel, 4003, Switzerland
| | - Reto Brun
- Swiss Tropical and Public Health Institute, Basel, 4002, Switzerland; University of Basel, Basel, 4003, Switzerland
| | - Ananya Paul
- Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA
| | - Pu Guo
- Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA
| | - W David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA
| | - David W Boykin
- Department of Chemistry, Georgia State University, Atlanta, GA, 30303, USA
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3
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Paul A, Farahat AA, Boykin DW, Wilson WD. Thermodynamic Factors That Drive Sequence-Specific DNA Binding of Designed, Synthetic Minor Groove Binding Agents. Life (Basel) 2022; 12:life12050681. [PMID: 35629349 PMCID: PMC9147024 DOI: 10.3390/life12050681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 11/16/2022] Open
Abstract
Ken Breslauer began studies on the thermodynamics of small cationic molecules binding in the DNA minor groove over 30 years ago, and the studies reported here are an extension of those ground-breaking reports. The goals of this report are to develop a detailed understanding of the binding thermodynamics of pyridine-based sequence-specific minor groove binders that have different terminal cationic groups. We apply biosensor-surface plasmon resonance and ITC methods to extend the understanding of minor groove binders in two directions: (i) by using designed, heterocyclic dicationic minor groove binders that can incorporate a G•C base pair (bp), with flanking AT base pairs, into their DNA recognition site, and bind to DNA sequences specifically; and (ii) by using a range of flanking AT sequences to better define molecular recognition of the minor groove. A G•C bp in the DNA recognition site causes a generally more negative binding enthalpy than with most previously used pure AT binding sites. The binding is enthalpy-driven at 25 °C and above. The flanking AT sequences also have a large effect on the binding energetics with the -AAAGTTT- site having the strongest affinity. As a result of these studies, we now have a much better understanding of the effects of the DNA sequence and compound structure on the molecular recognition and thermodynamics of minor groove complexes.
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Affiliation(s)
- Ananya Paul
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA; (A.P.); (A.A.F.); (D.W.B.)
| | - Abdelbasset A. Farahat
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA; (A.P.); (A.A.F.); (D.W.B.)
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
| | - David W. Boykin
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA; (A.P.); (A.A.F.); (D.W.B.)
| | - W. David Wilson
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA; (A.P.); (A.A.F.); (D.W.B.)
- Correspondence: ; Tel.: +1-404-413-5503; Fax: +1-404-413-5505
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4
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Zhang B, Jin Y, Zhang L, Wang H, Wang X. Pentamidine Ninety Years on: the Development and Applications of Pentamidine and its Analogs. Curr Med Chem 2022; 29:4602-4609. [PMID: 35289252 DOI: 10.2174/0929867329666220314121446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/25/2021] [Accepted: 01/07/2022] [Indexed: 11/22/2022]
Abstract
Pentamidine, an FDA-approved human drug for many protozoal infections, was initially synthesized in the late 1930s and first reported to be curative for parasitosis in the 1940s. After ninety years of sometimes quiet growth, pentamidine and its derivatives have gone far beyond antibacterial agents, including but not limited to the ligands of DNA minor groove, modulators of PPIs (protein-protein interactions) of the transmembrane domain 5 of lateral membrane protein 1, and the blockers of the SARS-CoV-2 3a channel. This mini review highlights the development and applications of pentamidine and its analogs, aiming to provide insights for further developing pentamidine derivatives in the following decades.
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Affiliation(s)
- Bo Zhang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, China;
- Department of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Yushan Jin
- Department of Immunology and Department of Cell & Systems Biology, University of Toronto, Toronto, M5S 3G3, Canada
| | - Lei Zhang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, China
| | - Hongshuang Wang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, China
| | - Xiaohui Wang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, China;
- Department of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, Anhui, China
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5
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Farahat AA, Iwamoto S, Roche M, Boykin DW. Facile synthesis of benzobisimidazole and bibenzimidazole‐based bisnitriles as potential precursors for
DNA
minor groove binders. J Heterocycl Chem 2021. [DOI: 10.1002/jhet.4353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Abdelbasset A. Farahat
- Master of Pharmaceutical Sciences Program California Northstate University Elk Grove California USA
- Faculty of Pharmacy Mansoura University Mansoura Egypt
| | - Satori Iwamoto
- Master of Pharmaceutical Sciences Program California Northstate University Elk Grove California USA
| | - Michael Roche
- Master of Pharmaceutical Sciences Program California Northstate University Elk Grove California USA
| | - David W. Boykin
- Chemistry Department Georgia State University Atlanta Georgia USA
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6
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Largy E, König A, Ghosh A, Ghosh D, Benabou S, Rosu F, Gabelica V. Mass Spectrometry of Nucleic Acid Noncovalent Complexes. Chem Rev 2021; 122:7720-7839. [PMID: 34587741 DOI: 10.1021/acs.chemrev.1c00386] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nucleic acids have been among the first targets for antitumor drugs and antibiotics. With the unveiling of new biological roles in regulation of gene expression, specific DNA and RNA structures have become very attractive targets, especially when the corresponding proteins are undruggable. Biophysical assays to assess target structure as well as ligand binding stoichiometry, affinity, specificity, and binding modes are part of the drug development process. Mass spectrometry offers unique advantages as a biophysical method owing to its ability to distinguish each stoichiometry present in a mixture. In addition, advanced mass spectrometry approaches (reactive probing, fragmentation techniques, ion mobility spectrometry, ion spectroscopy) provide more detailed information on the complexes. Here, we review the fundamentals of mass spectrometry and all its particularities when studying noncovalent nucleic acid structures, and then review what has been learned thanks to mass spectrometry on nucleic acid structures, self-assemblies (e.g., duplexes or G-quadruplexes), and their complexes with ligands.
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Affiliation(s)
- Eric Largy
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Alexander König
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Anirban Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Debasmita Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Sanae Benabou
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Frédéric Rosu
- Univ. Bordeaux, CNRS, INSERM, IECB, UMS 3033, F-33600 Pessac, France
| | - Valérie Gabelica
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
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7
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Guo P, Farahat AA, Paul A, Kumar A, Boykin DW, Wilson WD. Extending the σ-Hole Motif for Sequence-Specific Recognition of the DNA Minor Groove. Biochemistry 2020; 59:1756-1768. [PMID: 32293884 DOI: 10.1021/acs.biochem.0c00090] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The majority of current drugs against diseases, such as cancer, can bind to one or more sites in a protein and inhibit its activity. There are, however, well-known limits on the number of druggable proteins, and complementary current drugs with compounds that could selectively target DNA or RNA would greatly enhance the availability of cellular probes and therapeutic progress. We are focusing on the design of sequence-specific DNA minor groove binders that, for example, target the promoter sites of transcription factors involved in a disease. We have started with AT-specific minor groove binders that are known to enter human cells and have entered clinical trials. To broaden the sequence-specific recognition of these compounds, several modules that have H-bond acceptors that strongly and specifically recognize G·C base pairs were identified. A lead module is a thiophene-N-alkyl-benzimidazole σ-hole-based system with terminal phenyl-amidines that have excellent affinity and selectivity for a G·C base pair in the minor groove. Efforts are now focused on optimizing this module. In this work, we are evaluating modifications to the compound aromatic system with the goal of improving GC selectivity and affinity. The lead compounds retain the thiophene-N-alkyl-BI module but have halogen substituents adjacent to an amidine group on the terminal phenyl-amidine. The optimum compounds must have strong affinity and specificity with a residence time of at least 100 s.
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Affiliation(s)
- Pu Guo
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street Southeast, Atlanta, Georgia 30303, United States
| | - Abdelbasset A Farahat
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street Southeast, Atlanta, Georgia 30303, United States.,Master of Pharmaceutical Sciences Program, California Northstate University, 9700 West Taron Drive, Elk Grove, California 95757, United States
| | - Ananya Paul
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street Southeast, Atlanta, Georgia 30303, United States
| | - Arvind Kumar
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street Southeast, Atlanta, Georgia 30303, United States
| | - David W Boykin
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street Southeast, Atlanta, Georgia 30303, United States
| | - W David Wilson
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, 50 Decatur Street Southeast, Atlanta, Georgia 30303, United States
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8
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Farahat AA, Guo P, Shoeib H, Paul A, Boykin DW, Wilson WD. Small Sequence-Sensitive Compounds for Specific Recognition of the G⋅C Base Pair in DNA Minor Groove. Chemistry 2020; 26:4539-4551. [PMID: 31884714 PMCID: PMC7265973 DOI: 10.1002/chem.201904396] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/10/2019] [Indexed: 12/24/2022]
Abstract
A series of small diamidines with thiophene and modified N-alkylbenzimidazole σ-hole module represent specific binding to single G⋅C base pair (bp) DNA sequence. The variation of N-alkyl or aromatic rings were sensitive to microstructures of the DNA minor groove. Thirteen new compounds were synthesized to test their binding affinity and selectivity. The dicyanobenzimidazoles needed to synthesize the target diamidines were made via condensation/cyclization reactions of different aldehydes with different 3-amino-4-(alkyl- or phenyl-amino) benzonitriles. The final diamidines were synthesized using lithium bis-trimethylsilylamide (LiN[Si(CH3 )3 ]2 ) or Pinner methods. The newly synthesized compounds showed strong binding and selectivity to AAAGTTT compared to similar sequences AAATTT and AAAGCTTT investigated by several biophysical methods including biosensor-SPR, fluorescence spectroscopy, DNA thermal melting, ESI-MS spectrometry, circular dichroism, and molecular dynamics. The binding affinity results determined by fluorescence spectroscopy are in accordance with those obtained by biosensor-SPR. These small size single G⋅C bp highly specific binders extend the compound database for future biological applications.
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Affiliation(s)
- Abdelbasset A. Farahat
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St SE, Atlanta, GA 30303, USA
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
| | - Pu Guo
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St SE, Atlanta, GA 30303, USA
| | - Hadir Shoeib
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St SE, Atlanta, GA 30303, USA
| | - Ananya Paul
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St SE, Atlanta, GA 30303, USA
| | - David W. Boykin
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St SE, Atlanta, GA 30303, USA
| | - W. David Wilson
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St SE, Atlanta, GA 30303, USA
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9
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Carter EK, Laughlin-Toth S, Dodd T, Wilson WD, Ivanov I. Small molecule binders recognize DNA microstructural variations via an induced fit mechanism. Phys Chem Chem Phys 2019; 21:1841-1851. [PMID: 30629058 PMCID: PMC6497476 DOI: 10.1039/c8cp05537h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Regulation of gene-expression by specific targeting of protein-nucleic acid interactions has been a long-standing goal in medicinal chemistry. Transcription factors are considered "undruggable" because they lack binding sites well suited for binding small-molecules. In order to overcome this obstacle, we are interested in designing small molecules that bind to the corresponding promoter sequences and either prevent or modulate transcription factor association via an allosteric mechanism. To achieve this, we must design small molecules that are both sequence-specific and able to target G/C base pair sites. A thorough understanding of the relationship between binding affinity and the structural aspects of the small molecule-DNA complex would greatly aid in rational design of such compounds. Here we present a comprehensive analysis of sequence-specific DNA association of a synthetic minor groove binder using long timescale molecular dynamics. We show how binding selectivity arises from a combination of structural factors. Our results provide a framework for the rational design and optimization of synthetic small molecules in order to improve site-specific targeting of DNA for therapeutic uses in the design of selective DNA binders targeting transcription regulation.
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Affiliation(s)
- E. Kathleen Carter
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
| | - Sarah Laughlin-Toth
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Thomas Dodd
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
| | - W. David Wilson
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
| | - Ivaylo Ivanov
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA. ;
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10
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Bhaduri S, Ranjan N, Arya DP. An overview of recent advances in duplex DNA recognition by small molecules. Beilstein J Org Chem 2018; 14:1051-1086. [PMID: 29977379 PMCID: PMC6009268 DOI: 10.3762/bjoc.14.93] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 04/06/2018] [Indexed: 12/13/2022] Open
Abstract
As the carrier of genetic information, the DNA double helix interacts with many natural ligands during the cell cycle, and is amenable to such intervention in diseases such as cancer biogenesis. Proteins bind DNA in a site-specific manner, not only distinguishing between the geometry of the major and minor grooves, but also by making close contacts with individual bases within the local helix architecture. Over the last four decades, much research has been reported on the development of small non-natural ligands as therapeutics to either block, or in some cases, mimic a DNA–protein interaction of interest. This review presents the latest findings in the pursuit of novel synthetic DNA binders. This article provides recent coverage of major strategies (such as groove recognition, intercalation and cross-linking) adopted in the duplex DNA recognition by small molecules, with an emphasis on major works of the past few years.
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Affiliation(s)
| | - Nihar Ranjan
- National Institute of Pharmaceutical Education and Research (NIPER), Raebareli 122003, India
| | - Dev P Arya
- NUBAD, LLC, 900B West Faris Rd., Greenville 29605, SC, USA.,Clemson University, Hunter Laboratory, Clemson 29634, SC, USA
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11
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Indole and Benzimidazole Bichalcophenes: Synthesis, DNA Binding and Antiparasitic Activity. Eur J Med Chem 2017; 143:1590-1596. [PMID: 29126729 PMCID: PMC5744864 DOI: 10.1016/j.ejmech.2017.10.056] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 10/13/2017] [Accepted: 10/18/2017] [Indexed: 11/20/2022]
Abstract
A novel series of indole and benzimidazole bichalcophene diamidine derivatives were prepared to study their antimicrobial activity against the tropical parasites causing African sleeping sickness and malaria. The dicyanoindoles needed to synthesize the target diamidines were obtained through Stille coupling reactions while the bis-cyanobenzimidazoles intermediates were made via condensation/cyclization reactions of different aldehydes with 4-cyano-1,2-diaminobenzene. Different amidine synthesis methodologies namely, lithium bis-trimethylsilylamide (LiN[Si(CH3)3]2) and Pinner methods were used to prepare the diamidines. Both types (indole and benzimidazole) derivatives of the new diamidines bind strongly with the DNA minor groove and generally show excellent in vitro antitrypanosomal activity. The diamidino-indole derivatives also showed excellent in vitro antimalarial activity while their benzimidazole counterparts were generally less active. Compound 7c was highly active in vivo and cured all mice infected with Trypanosoma brucei rhodesiense, a model that mimics the acute stage of African sleeping sickness, at a low dose of 4 × 5 mg/kg i.p. and hence 7c is more potent in vivo than pentamidine.
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12
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Laughlin-Toth S, Carter EK, Ivanov I, Wilson WD. DNA microstructure influences selective binding of small molecules designed to target mixed-site DNA sequences. Nucleic Acids Res 2017; 45:1297-1306. [PMID: 28180310 PMCID: PMC5388402 DOI: 10.1093/nar/gkw1232] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/18/2016] [Accepted: 11/23/2016] [Indexed: 12/18/2022] Open
Abstract
Specific targeting of protein–nucleic acid interactions is an area of current interest, for example, in the regulation of gene-expression. Most transcription factor proteins bind in the DNA major groove; however, we are interested in an approach using small molecules to target the minor groove to control expression by an allosteric mechanism. In an effort to broaden sequence recognition of DNA-targeted-small-molecules to include both A·T and G·C base pairs, we recently discovered that the heterocyclic diamidine, DB2277, forms a strong monomer complex with a DNA sequence containing 5΄-AAAGTTT-3΄. Competition mass spectrometry and surface plasmon resonance identified new monomer complexes, as well as unexpected binding of two DB2277 with certain sequences. Inherent microstructural differences within the experimental DNAs were identified through computational analyses to understand the molecular basis for recognition. These findings emphasize the critical nature of the DNA minor groove microstructure for sequence-specific recognition and offer new avenues to design synthetic small molecules for effective regulation of gene-expression.
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Affiliation(s)
- Sarah Laughlin-Toth
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA
| | - E Kathleen Carter
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA
| | - Ivaylo Ivanov
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA
| | - W David Wilson
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, USA
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13
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Guo P, Paul A, Kumar A, Harika NK, Wang S, Farahat AA, Boykin DW, Wilson WD. A modular design for minor groove binding and recognition of mixed base pair sequences of DNA. Chem Commun (Camb) 2017; 53:10406-10409. [PMID: 28880316 PMCID: PMC5616130 DOI: 10.1039/c7cc06246j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The design and synthesis of compounds that target mixed, AT/GC, DNA sequences is described. The design concept connects two N-methyl-benzimidazole-thiophene single GC recognition units with a flexible linker that lets the compound fit the shape and twist of the DNA minor groove while covering a full turn of the double helix.
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Affiliation(s)
- Pu Guo
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St Se, Atlanta, GA 30303-3083, USA.
| | - Ananya Paul
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St Se, Atlanta, GA 30303-3083, USA.
| | - Arvind Kumar
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St Se, Atlanta, GA 30303-3083, USA.
| | - Narinder K Harika
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St Se, Atlanta, GA 30303-3083, USA.
| | - Siming Wang
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St Se, Atlanta, GA 30303-3083, USA.
| | - Abdelbasset A Farahat
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St Se, Atlanta, GA 30303-3083, USA.
| | - David W Boykin
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St Se, Atlanta, GA 30303-3083, USA.
| | - W David Wilson
- Department of Chemistry and Center for Diagnostics and Therapeutics Georgia State University, 50 Decatur St Se, Atlanta, GA 30303-3083, USA.
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14
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Farahat AA, Kumar A, Say M, Wenzler T, Brun R, Paul A, Wilson WD, Boykin DW. Exploration of DAPI analogues: Synthesis, antitrypanosomal activity, DNA binding and fluorescence properties. Eur J Med Chem 2017; 128:70-78. [PMID: 28152428 PMCID: PMC5341734 DOI: 10.1016/j.ejmech.2017.01.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/17/2017] [Accepted: 01/23/2017] [Indexed: 02/05/2023]
Abstract
The DAPI structure has been modified by replacing the phenyl group with substituted phenyl or heteroaryl rings. Twelve amidines were synthesized and their DNA binding, fluorescence properties, in vitro and in vivo activities were evaluated. These compounds are shown to bind in the DNA minor groove with high affinity, and exhibit superior in vitro antitrypanosomal activity to that of DAPI. Six new diamidines (5b, 5c, 5d, 5e, 5f and 5j) exhibit superior in vivo activity to that of DAPI and four of these compounds provide 100% animal cure at a low dose of 4 × 5 mg/kg i.p. in T. b. rhodesiense infected mice. Generally, the fluorescence properties of the new analogues are inferior to that of DAPI with the exception of compound 5i which shows a moderate increase in efficacy while compound 5k is comparable to DAPI.
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Affiliation(s)
- Abdelbasset A Farahat
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States; Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.
| | - Arvind Kumar
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Martial Say
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Tanja Wenzler
- Swiss Tropical and Public Health Institute, Basel 4002, Switzerland; University of Basel, Basel, 4003, Switzerland
| | - Reto Brun
- Swiss Tropical and Public Health Institute, Basel 4002, Switzerland; University of Basel, Basel, 4003, Switzerland
| | - Ananya Paul
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - W David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - David W Boykin
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
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15
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Farahat AA, Bennett-Vaughn C, Mineva EM, Kumar A, Wenzler T, Brun R, Liu Y, Wilson WD, Boykin DW. Synthesis, DNA binding and antitrypanosomal activity of benzimidazole analogues of DAPI. Bioorg Med Chem Lett 2016; 26:5907-5910. [PMID: 27843114 DOI: 10.1016/j.bmcl.2016.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 10/31/2016] [Accepted: 11/01/2016] [Indexed: 01/01/2023]
Abstract
A series of novel benzimidazole diamidines were prepared from the corresponding dicyano analogues either by applying Pinner methodology (5a-c, 10 and 13a) or by making amidoximes intermediates that were reduced to the corresponding amidines (15a-c). The new amidines were evaluated in vitro against the protozoan parasite Trypanosoma brucei rhodesiense (T. b. r.). The thiophene analogue 5b and the N-methyl compound 15a showed superior antitrypanosomal activity compared to that of the parent I.
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Affiliation(s)
- Abdelbasset A Farahat
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States; Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.
| | | | - Ekaterina M Mineva
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Arvind Kumar
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Tanja Wenzler
- Swiss Tropical and Public Health Institute, Basel 4002, Switzerland; University of Basel, Basel 4003, Switzerland
| | - Reto Brun
- Swiss Tropical and Public Health Institute, Basel 4002, Switzerland; University of Basel, Basel 4003, Switzerland
| | - Yang Liu
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - W David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - David W Boykin
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
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16
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Guo P, Paul A, Kumar A, Farahat AA, Kumar D, Wang S, Boykin DW, Wilson WD. The Thiophene "Sigma-Hole" as a Concept for Preorganized, Specific Recognition of G⋅C Base Pairs in the DNA Minor Groove. Chemistry 2016; 22:15404-15412. [PMID: 27624927 PMCID: PMC5214980 DOI: 10.1002/chem.201603422] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Indexed: 11/10/2022]
Abstract
In spite of its importance in cell function, targeting DNA is under-represented in the design of small molecules. A barrier to progress in this area is the lack of a variety of modules that recognize G⋅C base pairs (bp) in DNA sequences. To overcome this barrier, an entirely new design concept for modules that can bind to mixed G⋅C and A⋅T sequences of DNA is reported herein. Because of their successes in biological applications, minor-groove-binding heterocyclic cations were selected as the platform for design. Binding to A⋅T sequences requires hydrogen-bond donors whereas recognition of the G-NH2 requires an acceptor. The concept that we report herein uses pre-organized N-methylbenzimidazole (N-MeBI) thiophene modules for selective binding with mixed bp DNA sequences. The interaction between the thiophene sigma hole (positive electrostatic potential) and the electron-donor nitrogen of N-MeBI preorganizes the conformation for accepting an hydrogen bond from G-NH2 . The compound-DNA interactions were evaluated with a powerful array of biophysical methods and the results show that N-MeBI-thiophene monomer compounds can strongly and selectively recognize single G⋅C bp sequences. Replacing the thiophene with other moieties significantly reduces binding affinity and specificity, as predicted by the design concept. These results show that the use of molecular features, such as sigma-holes, can lead to new approaches for small molecules in biomolecular interactions.
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Affiliation(s)
- Pu Guo
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303-3083, USA
| | - Ananya Paul
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303-3083, USA
| | - Arvind Kumar
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303-3083, USA
| | - Abdelbasset A Farahat
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303-3083, USA
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt
| | - Dhiraj Kumar
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303-3083, USA
| | - Siming Wang
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303-3083, USA
| | - David W Boykin
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303-3083, USA
| | - W David Wilson
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30303-3083, USA.
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17
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Abou-Elkhair RAI, Hassan AEA, Boykin DW, Wilson WD. Lithium Hexamethyldisilazane Transformation of Transiently Protected 4-Aza/Benzimidazole Nitriles to Amidines and their Dimethyl Sulfoxide Mediated Imidazole Ring Formation. Org Lett 2016; 18:4714-7. [PMID: 27607538 DOI: 10.1021/acs.orglett.6b02359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Trimethylsilyl-transient protection successfully allowed the use of lithium hexamethyldisilazane to prepare benzimidazole (BI) and 4-azabenzimidazole (azaBI) amidines from nitriles in 58-88% yields. This strategy offers a much better choice to prepare BI/azaBI amidines than the lengthy, low-yielding Pinner reaction. Synthesis of aza/benzimidazole rings from aromatic diamines and aldehydes was affected in dimethyl sulfoxide in 10-15 min, while known procedures require long time and purification. These methods are important for the BI/azaBI-based drug industry and for developing specific DNA binders for expanded therapeutic applications.
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Affiliation(s)
- Reham A I Abou-Elkhair
- Department of Chemistry, Georgia State University , Atlanta, Georgia 30303, United States.,Applied Nucleic Acids Research Center & Chemistry Department, Faculty of Sciences, Zagazig University , Zagazig 44519, Egypt
| | - Abdalla E A Hassan
- Applied Nucleic Acids Research Center & Chemistry Department, Faculty of Sciences, Zagazig University , Zagazig 44519, Egypt
| | - David W Boykin
- Department of Chemistry, Georgia State University , Atlanta, Georgia 30303, United States
| | - W David Wilson
- Department of Chemistry, Georgia State University , Atlanta, Georgia 30303, United States
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18
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Antiprion Activity of DB772 and Related Monothiophene- and Furan-Based Analogs in a Persistently Infected Ovine Microglia Culture System. Antimicrob Agents Chemother 2016; 60:5467-82. [PMID: 27381401 PMCID: PMC4997874 DOI: 10.1128/aac.00811-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/26/2016] [Indexed: 01/26/2023] Open
Abstract
The transmissible spongiform encephalopathies are fatal neurodegenerative disorders characterized by the misfolding of the native cellular prion protein (PrPC) into the accumulating, disease-associated isoform (PrPSc). Despite extensive research into the inhibition of prion accumulation, no effective treatment exists. Previously, we demonstrated the inhibitory activity of DB772, a monocationic phenyl-furan-benzimidazole, against PrPSc accumulation in sheep microglial cells. In an effort to determine the effect of structural substitutions on the antiprion activity of DB772, we employed an in vitro strategy to survey a library of structurally related, monothiophene- and furan-based compounds for improved inhibitory activity. Eighty-nine compounds were screened at 1 μM for effects on cell viability and prion accumulation in a persistently infected ovine microglia culture system. Eleven compounds with activity equivalent to or higher than that of DB772 were identified as preliminary hit compounds. For the preliminary hits, cytotoxicities and antiprion activities were compared to calculate the tissue culture selectivity index. A structure-activity relationship (SAR) analysis was performed to determine molecular components contributing to antiprion activity. To investigate potential mechanisms of inhibition, effects on PrPC and PrPSc were examined. While inhibition of total PrPC was not observed, the results suggest that a potential target for inhibition at biologically relevant concentrations is through PrPC misfolding to PrPSc. Further, SAR analysis suggests that two structural elements were associated with micromolar antiprion activity. Taken together, the described data provide a foundation for deeper investigation into untested DB compounds and in the design of effective therapeutics.
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Laughlin S, Wilson WD. May the Best Molecule Win: Competition ESI Mass Spectrometry. Int J Mol Sci 2015; 16:24506-31. [PMID: 26501262 PMCID: PMC4632762 DOI: 10.3390/ijms161024506] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 09/18/2015] [Accepted: 10/09/2015] [Indexed: 02/07/2023] Open
Abstract
Electrospray ionization mass spectrometry has become invaluable in the characterization of macromolecular biological systems such as nucleic acids and proteins. Recent advances in the field of mass spectrometry and the soft conditions characteristic of electrospray ionization allow for the investigation of non-covalent interactions among large biomolecules and ligands. Modulation of genetic processes through the use of small molecule inhibitors with the DNA minor groove is gaining attention as a potential therapeutic approach. In this review, we discuss the development of a competition method using electrospray ionization mass spectrometry to probe the interactions of multiple DNA sequences with libraries of minor groove binding molecules. Such an approach acts as a high-throughput screening method to determine important information including the stoichiometry, binding mode, cooperativity, and relative binding affinity. In addition to small molecule-DNA complexes, we highlight other applications in which competition mass spectrometry has been used. A competitive approach to simultaneously investigate complex interactions promises to be a powerful tool in the discovery of small molecule inhibitors with high specificity and for specific, important DNA sequences.
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Affiliation(s)
- Sarah Laughlin
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA.
| | - W David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA.
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20
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Paul A, Nanjunda R, Kumar A, Laughlin S, Nhili R, Depauw S, Deuser SS, Chai Y, Chaudhary AS, David-Cordonnier MH, Boykin DW, Wilson WD. Mixed up minor groove binders: Convincing A·T specific compounds to recognize a G·C base pair. Bioorg Med Chem Lett 2015; 25:4927-4932. [PMID: 26051649 DOI: 10.1016/j.bmcl.2015.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 05/06/2015] [Indexed: 01/08/2023]
Abstract
DNA minor-groove-binding compounds have limited biological applications, in part due to problems with sequence specificity that cause off-target effects. A model to enhance specificity has been developed with the goal of preparing compounds that bind to two AT sites separated by G·C base pairs. Compounds of interest were probed using thermal melting, circular dichroism, mass spectrometry, biosensor-SPR, and molecular modeling methods. A new minor groove binder that can strongly and specifically recognize a single G·C base pair with flanking AT sequences has been prepared. This multi-site DNA recognition mode offers novel design principles to recognize entirely new DNA motifs.
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Affiliation(s)
- Ananya Paul
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Rupesh Nanjunda
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Arvind Kumar
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Sarah Laughlin
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Raja Nhili
- UMR-S1172-Jean-Pierre Aubert Research Centre (JPARC), INSERM-University of Lille and Centre Hospitalier of Lille, Institut pour la Recherche sur le Cancer de Lille, Place de Verdun, F-59045 Lille Cedex, France
| | - Sabine Depauw
- UMR-S1172-Jean-Pierre Aubert Research Centre (JPARC), INSERM-University of Lille and Centre Hospitalier of Lille, Institut pour la Recherche sur le Cancer de Lille, Place de Verdun, F-59045 Lille Cedex, France
| | - Shelby Sheldon Deuser
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Yun Chai
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Arpana S Chaudhary
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Marie-Hélène David-Cordonnier
- UMR-S1172-Jean-Pierre Aubert Research Centre (JPARC), INSERM-University of Lille and Centre Hospitalier of Lille, Institut pour la Recherche sur le Cancer de Lille, Place de Verdun, F-59045 Lille Cedex, France
| | - David W Boykin
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - W David Wilson
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA.
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