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Egu SA, Ali I, Khan KM, Chigurupati S, Qureshi U, Salar U, Ul-Haq Z, Almahmoud SA, Felemban SG, Ali M, Taha M. Rhodanine-benzamides as potential hits for α-amylase enzyme inhibitors and radical (DPPH and ABTS) scavengers. Mol Divers 2024:10.1007/s11030-024-10813-z. [PMID: 38446373 DOI: 10.1007/s11030-024-10813-z] [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: 11/13/2022] [Accepted: 01/19/2024] [Indexed: 03/07/2024]
Abstract
A series of 3-substituted and 3,5-disubstituted rhodanine-based derivatives were synthesized from 3-aminorhodanine and examined for α-amylase inhibitory, DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities in vitro. These derivatives displayed significant α-amylase inhibitory potential with IC50 values of 11.01-56.04 µM in comparison to standard acarbose (IC50 = 9.08 ± 0.07 µM). Especially, compounds 7 (IC50 = 11.01 ± 0.07 µM) and 8 (IC50 = 12.01 ± 0.07 µM) showed highest α-amylase inhibitory activities among the whole series. In addition to α-amylase inhibitory activity, all compounds also demonstrated significant scavenging activities against DPPH and ABTS radicals, with IC50 values ranging from 12.24 to 57.33 and 13.29-59.09 µM, respectively, as compared to the standard ascorbic acid (IC50 = 15.08 ± 0.03 µM for DPPH; IC50 = 16.09 ± 0.17 µM for ABTS). These findings reveal that the nature and position of the substituents on the phenyl ring(s) are crucial for variation in the activities. The structure-activity relationship (SAR) revealed that the compounds bearing an electron-withdrawing group (EWG) at para substitution possessed the highest activity. In kinetic studies, only the km value was changed, with no observed changes in Vmax, indicating a competitive inhibition. Molecular docking studies revealed important interactions between compounds and the α-amylase active pocket. Further advanced research needs to perform on the identified compounds in order to obtain potential antidiabetic agents.
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Affiliation(s)
- Samuel Attah Egu
- Department of Pure and Industrial Chemistry, Kogi State University, Anyigba, Kogi State, Nigeria
- International Center for Chemical and Biological Sciences, H. E. J. Research Institute of Chemistry, University of Karachi, Karachi, 75270, Pakistan
| | - Irfan Ali
- International Center for Chemical and Biological Sciences, H. E. J. Research Institute of Chemistry, University of Karachi, Karachi, 75270, Pakistan
| | - Khalid Mohammed Khan
- International Center for Chemical and Biological Sciences, H. E. J. Research Institute of Chemistry, University of Karachi, Karachi, 75270, Pakistan.
- Department of Clinical Pharmacy, Institute for Research and Medical Consultations [IRMC], Imam Abdulrahman Bin Faisal University, P.O. Box 31441, Dammam, Kingdom of Saudi Arabia.
- Pakistan Academy of Science, 3-Constitution Avenue, G-5/2, Islamabad, 44000, Pakistan.
| | - Sridevi Chigurupati
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Qassim University, Buraydah, 52571, Kingdom of Saudi Arabia
| | - Urooj Qureshi
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Uzma Salar
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Zaheer Ul-Haq
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Suliman A Almahmoud
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Qassim University, Buraydah, 52571, Kingdom of Saudi Arabia
| | - Shatha Ghazi Felemban
- Department of Medical Laboratory Science, Fakeeh College for Medical Sciences, Jeddah, 21461, Kingdom of Saudi Arabia
| | - Mohsin Ali
- Department of Chemistry, University of Karachi, Karachi, 75270, Pakistan
| | - Muhammad Taha
- Department of Clinical Pharmacy, Institute for Research and Medical Consultations [IRMC], Imam Abdulrahman Bin Faisal University, P.O. Box 31441, Dammam, Kingdom of Saudi Arabia
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2
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Radford HM, Toft CJ, Sorenson AE, Schaeffer PM. Inhibition of Replication Fork Formation and Progression: Targeting the Replication Initiation and Primosomal Proteins. Int J Mol Sci 2023; 24:ijms24108802. [PMID: 37240152 DOI: 10.3390/ijms24108802] [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: 03/31/2023] [Revised: 05/02/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Over 1.2 million deaths are attributed to multi-drug-resistant (MDR) bacteria each year. Persistence of MDR bacteria is primarily due to the molecular mechanisms that permit fast replication and rapid evolution. As many pathogens continue to build resistance genes, current antibiotic treatments are being rendered useless and the pool of reliable treatments for many MDR-associated diseases is thus shrinking at an alarming rate. In the development of novel antibiotics, DNA replication is still a largely underexplored target. This review summarises critical literature and synthesises our current understanding of DNA replication initiation in bacteria with a particular focus on the utility and applicability of essential initiation proteins as emerging drug targets. A critical evaluation of the specific methods available to examine and screen the most promising replication initiation proteins is provided.
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Affiliation(s)
- Holly M Radford
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia
| | - Casey J Toft
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia
| | - Alanna E Sorenson
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia
| | - Patrick M Schaeffer
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia
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3
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Yararli K, Ozer EB, Bayindir S, Caglayan C, Turkes C, Beydemir S. The synthesis, biological evaluation and in silico studies of asymmetric 3,5-diaryl-rhodanines as novel inhibitors of human carbonic anhydrase isoenzymes. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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4
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The solvent-controlled regioselective synthesis of 3-amino-5-aryl-rhodanines as novel inhibitors of human carbonic anhydrase enzymes. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.132896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Abstract
Staphylococcus aureus is a common cause of both superficial and invasive infections of humans and animals. Despite a potent host response and apparently appropriate antibiotic therapy, staphylococcal infections frequently become chronic or recurrent, demonstrating a remarkable ability of S. aureus to withstand the hostile host environment. There is growing evidence that staphylococcal DNA repair makes important contributions to the survival of the pathogen in host tissues, as well as promoting the emergence of mutants that resist host defenses and antibiotics. While much of what we know about DNA repair in S. aureus is inferred from studies with model organisms, the roles of specific repair mechanisms in infection are becoming clear and differences with Bacillus subtilis and Escherichia coli have been identified. Furthermore, there is growing interest in staphylococcal DNA repair as a target for novel therapeutics that sensitize the pathogen to host defenses and antibiotics. In this review, we discuss what is known about staphylococcal DNA repair and its role in infection, examine how repair in S. aureus is similar to, or differs from, repair in well-characterized model organisms, and assess the potential of staphylococcal DNA repair as a novel therapeutic target.
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6
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Inhibition effect of rhodanines containing benzene moieties on pentose phosphate pathway enzymes and molecular docking. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128700] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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7
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Edwards MR, Liu G, De S, Sourimant J, Pietzsch C, Johnson B, Amarasinghe GK, Leung DW, Bukreyev A, Plemper RK, Aron Z, Bowlin TL, Moir DT, Basler CF. Small Molecule Compounds That Inhibit Antioxidant Response Gene Expression in an Inducer-Dependent Manner. ACS Infect Dis 2020; 6:489-502. [PMID: 31899866 PMCID: PMC7793009 DOI: 10.1021/acsinfecdis.9b00416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Marburg virus (MARV) causes severe disease in humans and is known to activate nuclear factor erythroid 2-related factor 2 (Nrf2), the major transcription factor of the antioxidant response. Canonical activation of Nrf2 involves oxidative or electrophilic stress that prevents Kelch-like ECH-associated protein 1 (Keap1) targeted degradation of Nrf2, leading to Nrf2 stabilization and activation of the antioxidant response. MARV activation of Nrf2 is noncanonical with the MARV VP24 protein (mVP24) interacting with Keap1, freeing Nrf2 from degradation. A high-throughput screening (HTS) assay was developed to identify inhibitors of mVP24-induced Nrf2 activity and used to screen more than 55,000 compounds. Hit compounds were further screened against secondary HTS assays for the inhibition of antioxidant activity induced by additional canonical and noncanonical mechanisms. This pipeline identified 14 compounds that suppress the response, dependent on the inducer, with 50% inhibitory concentrations below 5 μM and selectivity index values greater than 10. Notably, several of the identified compounds specifically inhibit mVP24-induced Nrf2 activity.
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Affiliation(s)
- Megan R. Edwards
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Gai Liu
- Microbiotix Inc, 1 Innovation Drive, Worcester MA 01605, United States
| | - Sampriti De
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Julien Sourimant
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Colette Pietzsch
- Department of Pathology, Galveston National Laboratory, University of Texas Medical Branch at Galveston, Galveston, TX 77555, United States
| | - Britney Johnson
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Gaya K. Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Daisy W. Leung
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Alexander Bukreyev
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, United States
- Department of Microbiology and Immunology, Galveston National Laboratory, University of Texas Medical Branch at Galveston, Galveston, TX 77555, United States
| | - Richard K. Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Zachary Aron
- Microbiotix Inc, 1 Innovation Drive, Worcester MA 01605, United States
| | - Terry L. Bowlin
- Microbiotix Inc, 1 Innovation Drive, Worcester MA 01605, United States
| | - Donald T. Moir
- Microbiotix Inc, 1 Innovation Drive, Worcester MA 01605, United States
| | - Christopher F. Basler
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
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8
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Yi L, Lü X. New Strategy on Antimicrobial-resistance: Inhibitors of DNA Replication Enzymes. Curr Med Chem 2019; 26:1761-1787. [PMID: 29110590 DOI: 10.2174/0929867324666171106160326] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/31/2017] [Accepted: 10/30/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND Antimicrobial resistance is found in all microorganisms and has become one of the biggest threats to global health. New antimicrobials with different action mechanisms are effective weapons to fight against antibiotic-resistance. OBJECTIVE This review aims to find potential drugs which can be further developed into clinic practice and provide clues for developing more effective antimicrobials. METHODS DNA replication universally exists in all living organisms and is a complicated process in which multiple enzymes are involved in. Enzymes in bacterial DNA replication of initiation and elongation phases bring abundant targets for antimicrobial development as they are conserved and indispensable. In this review, enzyme inhibitors of DNA helicase, DNA primase, topoisomerases, DNA polymerase and DNA ligase were discussed. Special attentions were paid to structures, activities and action modes of these enzyme inhibitors. RESULTS Among these enzymes, type II topoisomerase is the most validated target with abundant inhibitors. For type II topoisomerase inhibitors (excluding quinolones), NBTIs and benzimidazole urea derivatives are the most promising inhibitors because of their good antimicrobial activity and physicochemical properties. Simultaneously, DNA gyrase targeted drugs are particularly attractive in the treatment of tuberculosis as DNA gyrase is the sole type II topoisomerase in Mycobacterium tuberculosis. Relatively, exploitation of antimicrobial inhibitors of the other DNA replication enzymes are primeval, in which inhibitors of topo III are even blank so far. CONCLUSION This review demonstrates that inhibitors of DNA replication enzymes are abundant, diverse and promising, many of which can be developed into antimicrobials to deal with antibioticresistance.
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Affiliation(s)
- Lanhua Yi
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi Province 712100, China
| | - Xin Lü
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi Province 712100, China
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9
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Bayindir S, Caglayan C, Karaman M, Gülcin İ. The green synthesis and molecular docking of novel N-substituted rhodanines as effective inhibitors for carbonic anhydrase and acetylcholinesterase enzymes. Bioorg Chem 2019; 90:103096. [PMID: 31284100 DOI: 10.1016/j.bioorg.2019.103096] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/24/2019] [Accepted: 06/27/2019] [Indexed: 12/30/2022]
Abstract
Recently, inhibition effects of enzymes such as acetylcholinesterase (AChE) and carbonic anhydrase (CA) has appeared as a promising approach for pharmacological intervention in a variety of disorders such as epilepsy, Alzheimer's disease and obesity. For this purpose, novel N-substituted rhodanine derivatives (RhAs) were synthesized by a green synthetic approach over one-pot reaction. Following synthesis the novel compounds, RhAs derivatives were tested against AChE and cytosolic carbonic anhydrase I, and II (hCAs I, and II) isoforms. As a result of this study, inhibition constant (Ki) were found in the range of 66.35 ± 8.35 to 141.92 ± 12.63 nM for AChE, 43.55 ± 14.20 to 89.44 ± 24.77 nM for hCA I, and 16.97 ± 1.42 to 64.57 ± 13.27 nM for hCA II, respectively. Binding energies were calculated with docking studies as -5.969, -5.981, and -9.121 kcal/mol for hCA I, hCA II, and AChE, respectively.
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Affiliation(s)
- Sinan Bayindir
- Department of Chemistry, Faculty of Sciences and Arts, Bingol University, 12000-Bingöl, Turkey.
| | - Cuneyt Caglayan
- Department of Biochemistry, Faculty of Veterinary Medicine, Bingol University, 12000-Bingöl, Turkey
| | - Muhammet Karaman
- Department of Molecular Biology and Genetics, Faculty of Arts and Science, Kilis 7 Aralik University, 79000-Kilis, Turkey
| | - İlhami Gülcin
- Department of Chemistry, Faculty of Sciences, Atatürk University, 25240-Erzurum, Turkey.
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10
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Veale CGL. Unpacking the Pathogen Box-An Open Source Tool for Fighting Neglected Tropical Disease. ChemMedChem 2019; 14:386-453. [PMID: 30614200 DOI: 10.1002/cmdc.201800755] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Indexed: 12/13/2022]
Abstract
The Pathogen Box is a 400-strong collection of drug-like compounds, selected for their potential against several of the world's most important neglected tropical diseases, including trypanosomiasis, leishmaniasis, cryptosporidiosis, toxoplasmosis, filariasis, schistosomiasis, dengue virus and trichuriasis, in addition to malaria and tuberculosis. This library represents an ensemble of numerous successful drug discovery programmes from around the globe, aimed at providing a powerful resource to stimulate open source drug discovery for diseases threatening the most vulnerable communities in the world. This review seeks to provide an in-depth analysis of the literature pertaining to the compounds in the Pathogen Box, including structure-activity relationship highlights, mechanisms of action, related compounds with reported activity against different diseases, and, where appropriate, discussion on the known and putative targets of compounds, thereby providing context and increasing the accessibility of the Pathogen Box to the drug discovery community.
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Affiliation(s)
- Clinton G L Veale
- School of Chemistry and Physics, Pietermaritzburg Campus, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa
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11
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Polysaccharide deacetylases serve as new targets for the design of inhibitors against Bacillus anthracis and Bacillus cereus. Bioorg Med Chem 2018; 26:3845-3851. [DOI: 10.1016/j.bmc.2018.06.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/25/2018] [Accepted: 06/30/2018] [Indexed: 02/02/2023]
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12
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Zhou E, Seminara AB, Kim SK, Hall CL, Wang Y, Lee VT. Thiol-benzo-triazolo-quinazolinone Inhibits Alg44 Binding to c-di-GMP and Reduces Alginate Production by Pseudomonas aeruginosa. ACS Chem Biol 2017; 12:3076-3085. [PMID: 29091392 DOI: 10.1021/acschembio.7b00826] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that affects a large proportion of cystic fibrosis (CF) patients. CF patients have dehydrated mucus within the airways that leads to the inability of the mucociliary escalator to expel inhaled microbes. Once inhaled, P. aeruginosa can persist in the lungs of the CF patients for the remainder of their lives. During this chronic infection, a phenomenon called mucoid conversion can occur in which P. aeruginosa can mutate and inactivate their mucA gene. As a consequence, transcription of the alg operon is highly expressed, leading to the copious secretion of the alginate exopolysaccharide, which is associated with decreased lung function and increased CF patient morbidity and mortality. Alginate biosynthesis by P. aeruginosa is post-translationally regulated by bis(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), which binds to the receptor protein Alg44 to activate alginate production. The identification of small molecules that disrupt the binding of c-di-GMP to Alg44 could inhibit the ability of P. aeruginosa to produce alginate. In this work, a class of thiol-benzo-triazolo-quinazolinone compounds that inhibited Alg44 binding to c-di-GMP in vitro was identified after screening chemical libraries consisting of ∼50 000 chemical compounds. Thiol-benzo-triazolo-quinazolinones were shown to specifically inhibit Alg44-c-di-GMP interactions by forming a disulfide bond with the cysteine residue in the PilZ domain of Alg44. The more potent thiol-benzo-triazolo-quinazolinone had the ability to reduce P. aeruginosa alginate secretion by up to 30%. These compounds serve as leads in the development of novel inhibitors of alginate production by P. aeruginosa after mucoid conversion.
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Affiliation(s)
- Eric Zhou
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
| | - Anna B. Seminara
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
| | - Soo-Kyoung Kim
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
| | - Cherisse L. Hall
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
| | - Yan Wang
- Maryland Pathogen Research Institute, Bioscience Research Building, College Park, Maryland 20742, United States
- Proteomics
Core Facility, College of Computer, Mathematical and Natural Science, University of Maryland College Park, 0111 Biology Psychology Building, College Park, Maryland 20742, United States
| | - Vincent T. Lee
- Department
of Cell Biology and Molecular Genetics, University of Maryland, Bioscience Research Building, College Park, Maryland 20742, United States
- Maryland Pathogen Research Institute, Bioscience Research Building, College Park, Maryland 20742, United States
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13
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Reiche MA, Warner DF, Mizrahi V. Targeting DNA Replication and Repair for the Development of Novel Therapeutics against Tuberculosis. Front Mol Biosci 2017; 4:75. [PMID: 29184888 PMCID: PMC5694481 DOI: 10.3389/fmolb.2017.00075] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 10/31/2017] [Indexed: 12/11/2022] Open
Abstract
Mycobacterium tuberculosis is the etiological agent of tuberculosis (TB), an infectious disease which results in approximately 10 million incident cases and 1.4 million deaths globally each year, making it the leading cause of mortality from infection. An effective frontline combination chemotherapy exists for TB; however, this regimen requires the administration of four drugs in a 2 month long intensive phase followed by a continuation phase of a further 4 months with two of the original drugs, and is only effective for the treatment of drug-sensitive TB. The emergence and global spread of multidrug-resistant (MDR) as well as extensively drug-resistant (XDR) strains of M. tuberculosis, and the complications posed by co-infection with the human immunodeficiency virus (HIV) and other co-morbidities such as diabetes, have prompted urgent efforts to develop shorter regimens comprising new compounds with novel mechanisms of action. This demands that researchers re-visit cellular pathways and functions that are essential to M. tuberculosis survival and replication in the host but which are inadequately represented amongst the targets of current anti-mycobacterial agents. Here, we consider the DNA replication and repair machinery as a source of new targets for anti-TB drug development. Like most bacteria, M. tuberculosis encodes a complex array of proteins which ensure faithful and accurate replication and repair of the chromosomal DNA. Many of these are essential; so, too, are enzymes in the ancillary pathways of nucleotide biosynthesis, salvage, and re-cycling, suggesting the potential to inhibit replication and repair functions at multiple stages. To this end, we provide an update on the state of chemotherapeutic inhibition of DNA synthesis and related pathways in M. tuberculosis. Given the established links between genotoxicity and mutagenesis, we also consider the potential implications of targeting DNA metabolic pathways implicated in the development of drug resistance in M. tuberculosis, an organism which is unusual in relying exclusively on de novo mutations and chromosomal rearrangements for evolution, including the acquisition of drug resistance. In that context, we conclude by discussing the feasibility of targeting mutagenic pathways in an ancillary, “anti-evolution” strategy aimed at protecting existing and future TB drugs.
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Affiliation(s)
- Michael A Reiche
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Digby F Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Valerie Mizrahi
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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14
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Kapp E, Visser H, Sampson SL, Malan SF, Streicher EM, Foka GB, Warner DF, Omoruyi SI, Enogieru AB, Ekpo OE, Zindo FT, Joubert J. Versatility of 7-Substituted Coumarin Molecules as Antimycobacterial Agents, Neuronal Enzyme Inhibitors and Neuroprotective Agents. Molecules 2017; 22:molecules22101644. [PMID: 28973990 PMCID: PMC6151660 DOI: 10.3390/molecules22101644] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 09/21/2017] [Accepted: 09/27/2017] [Indexed: 11/16/2022] Open
Abstract
A medium-throughput screen using Mycobacterium tuberculosis H37Rv was employed to screen an in-house library of structurally diverse compounds for antimycobacterial activity. In this initial screen, eleven 7-substituted coumarin derivatives with confirmed monoamine oxidase-B and cholinesterase inhibitory activities, demonstrated growth inhibition of more than 50% at 50 µM. This prompted further exploration of all the 7-substituted coumarins in our library. Four compounds showed promising MIC99 values of 8.31–29.70 µM and 44.15–57.17 µM on M. tuberculosis H37Rv in independent assays using GAST-Fe and 7H9+OADC media, respectively. These compounds were found to bind to albumin, which may explain the variations in MIC between the two assays. Preliminary data showed that they were able to maintain their activity in fluoroquinolone resistant mycobacteria. Structure-activity relationships indicated that structural modification on position 4 and/or 7 of the coumarin scaffold could direct the selectivity towards either the inhibition of neuronal enzymes or the antimycobacterial effect. Moderate cytotoxicities were observed for these compounds and slight selectivity towards mycobacteria was indicated. Further neuroprotective assays showed significant neuroprotection for selected compounds irrespective of their neuronal enzyme inhibitory properties. These coumarin molecules are thus interesting lead compounds that may provide insight into the design of new antimicrobacterial and neuroprotective agents.
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Affiliation(s)
- Erika Kapp
- School of Pharmacy, Faculty of Natural Sciences, University of the Western Cape, Cape Town, Bellville 7550, South Africa.
| | - Hanri Visser
- DST/NRF Centre of Excellence in Biomedical Tuberculosis Research, SA MRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, University of Stellenbosch, Cape Town, Tygerberg 7505, South Africa.
| | - Samantha L Sampson
- DST/NRF Centre of Excellence in Biomedical Tuberculosis Research, SA MRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, University of Stellenbosch, Cape Town, Tygerberg 7505, South Africa.
| | - Sarel F Malan
- School of Pharmacy, Faculty of Natural Sciences, University of the Western Cape, Cape Town, Bellville 7550, South Africa.
| | - Elizabeth M Streicher
- DST/NRF Centre of Excellence in Biomedical Tuberculosis Research, SA MRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, University of Stellenbosch, Cape Town, Tygerberg 7505, South Africa.
| | - Germaine B Foka
- School of Pharmacy, Faculty of Natural Sciences, University of the Western Cape, Cape Town, Bellville 7550, South Africa.
| | - Digby F Warner
- Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research Unit, Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, Institute of Infectious Disease and Molecular Medicine and Department of Clinical Laboratory Sciences, University of Cape Town, Cape Town, Rondebosch 7700, South Africa.
| | - Sylvester I Omoruyi
- Department of Medical Biosciences, University of the Western Cape, Cape Town, Bellville 7550, South Africa.
| | - Adaze B Enogieru
- Department of Medical Biosciences, University of the Western Cape, Cape Town, Bellville 7550, South Africa.
| | - Okobi E Ekpo
- Department of Medical Biosciences, University of the Western Cape, Cape Town, Bellville 7550, South Africa.
| | - Frank T Zindo
- School of Pharmacy, Faculty of Natural Sciences, University of the Western Cape, Cape Town, Bellville 7550, South Africa.
| | - Jacques Joubert
- School of Pharmacy, Faculty of Natural Sciences, University of the Western Cape, Cape Town, Bellville 7550, South Africa.
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15
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Head BM, Rubinstein E, Meyers AFA. Alternative pre-approved and novel therapies for the treatment of anthrax. BMC Infect Dis 2016; 16:621. [PMID: 27809794 PMCID: PMC5094018 DOI: 10.1186/s12879-016-1951-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 10/22/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacillus anthracis, the causative agent of anthrax, is a spore forming and toxin producing rod-shaped bacterium that is classified as a category A bioterror agent. This pathogenic microbe can be transmitted to both animals and humans. Clinical presentation depends on the route of entry (direct contact, ingestion, injection or aerosolization) with symptoms ranging from isolated skin infections to more severe manifestations such as cardiac or pulmonary shock, meningitis, and death. To date, anthrax is treatable if antibiotics are administered promptly and continued for 60 days. However, if treatment is delayed or administered improperly, the patient's chances of survival are decreased drastically. In addition, antibiotics are ineffective against the harmful anthrax toxins and spores. Therefore, alternative therapeutics are essential. In this review article, we explore and discuss advances that have been made in anthrax therapy with a primary focus on alternative pre-approved and novel antibiotics as well as anti-toxin therapies. METHODS A literature search was conducted using the University of Manitoba search engine. Using this search engine allowed access to a greater variety of journals/articles that would have otherwise been restricted for general use. In order to be considered for discussion for this review, all articles must have been published later than 2009. RESULTS The alternative pre-approved antibiotics demonstrated high efficacy against B. anthracis both in vitro and in vivo. In addition, the safety profile and clinical pharmacology of these drugs were already known. Compounds that targeted underexploited bacterial processes (DNA replication, RNA synthesis, and cell division) were also very effective in combatting B. anthracis. In addition, these novel compounds prevented bacterial resistance. Targeting B. anthracis virulence, more specifically the anthrax toxins, increased the length of which treatment could be administered. CONCLUSIONS Several novel and pre-existing antibiotics, as well as toxin inhibitors, have shown increasing promise. A combination treatment that targets both bacterial growth and toxin production would be ideal and probably necessary for effectively combatting this armed bacterium.
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Affiliation(s)
- Breanne M. Head
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9 Canada
| | - Ethan Rubinstein
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9 Canada
| | - Adrienne F. A. Meyers
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB R3E 0J9 Canada
- National Laboratory for HIV Immunology, JC Wilt Infectious Disease Research Centre, Public Health Agency of Canada, Winnipeg, Canada
- Department of Medical Microbiology, University of Nairobi, Nairobi, Kenya
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16
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Painter RE, Adam GC, Arocho M, DiNunzio E, Donald RGK, Dorso K, Genilloud O, Gill C, Goetz M, Hairston NN, Murgolo N, Nare B, Olsen DB, Powles M, Racine F, Su J, Vicente F, Wisniewski D, Xiao L, Hammond M, Young K. Elucidation of DnaE as the Antibacterial Target of the Natural Product, Nargenicin. ACTA ACUST UNITED AC 2015; 22:1362-73. [PMID: 26456734 DOI: 10.1016/j.chembiol.2015.08.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 08/10/2015] [Accepted: 08/25/2015] [Indexed: 01/14/2023]
Abstract
Resistance to existing classes of antibiotics drives the need for discovery of novel compounds with unique mechanisms of action. Nargenicin A1, a natural product with limited antibacterial spectrum, was rediscovered in a whole-cell antisense assay. Macromolecular labeling in both Staphylococcus aureus and an Escherichia coli tolC efflux mutant revealed selective inhibition of DNA replication not due to gyrase or topoisomerase IV inhibition. S. aureus nargenicin-resistant mutants were selected at a frequency of ∼1 × 10(-9), and whole-genome resequencing found a single base-pair change in the dnaE gene, a homolog of the E. coli holoenzyme α subunit. A DnaE single-enzyme assay was exquisitely sensitive to inhibition by nargenicin, and other in vitro characterization studies corroborated DnaE as the target. Medicinal chemistry efforts may expand the spectrum of this novel mechanism antibiotic.
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Affiliation(s)
- Ronald E Painter
- In vitro Pharmacology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Gregory C Adam
- Screening and Protein Sciences, Merck Research Laboratories, North Wales, PA 19454, USA
| | - Marta Arocho
- Medicinal Chemistry, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Edward DiNunzio
- In vitro Pharmacology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Robert G K Donald
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Karen Dorso
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Olga Genilloud
- Centro de Investigación Básica (CIBE), Merck Sharp & Dhome de España, S.A., 28027 Madrid, Spain
| | - Charles Gill
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Michael Goetz
- Medicinal Chemistry, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Nichelle N Hairston
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Nicholas Murgolo
- Discovery Pharmacogenomics, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Bakela Nare
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - David B Olsen
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Maryann Powles
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Fred Racine
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Jing Su
- Medicinal Chemistry, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Francisca Vicente
- Centro de Investigación Básica (CIBE), Merck Sharp & Dhome de España, S.A., 28027 Madrid, Spain
| | - Douglas Wisniewski
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Li Xiao
- Medicinal Chemistry, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Milton Hammond
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Katherine Young
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA.
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17
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Unique helicase determinants in the essential conjugative TraI factor from Salmonella enterica serovar Typhimurium plasmid pCU1. J Bacteriol 2014; 196:3082-90. [PMID: 24936053 DOI: 10.1128/jb.01496-14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The widespread development of multidrug-resistant bacteria is a major health emergency. Conjugative DNA plasmids, which harbor a wide range of antibiotic resistance genes, also encode the protein factors necessary to orchestrate the propagation of plasmid DNA between bacterial cells through conjugative transfer. Successful conjugative DNA transfer depends on key catalytic components to nick one strand of the duplex DNA plasmid and separate the DNA strands while cell-to-cell transfer occurs. The TraI protein from the conjugative Salmonella plasmid pCU1 fulfills these key catalytic roles, as it contains both single-stranded DNA-nicking relaxase and ATP-dependent helicase domains within a single, 1,078-residue polypeptide. In this work, we unraveled the helicase determinants of Salmonella pCU1 TraI through DNA binding, ATPase, and DNA strand separation assays. TraI binds DNA substrates with high affinity in a manner influenced by nucleic acid length and the presence of a DNA hairpin structure adjacent to the nick site. TraI selectively hydrolyzes ATP, and mutations in conserved helicase motifs eliminate ATPase activity. Surprisingly, the absence of a relatively short (144-residue) domain at the extreme C terminus of the protein severely diminishes ATP-dependent strand separation. Collectively, these data define the helicase motifs of the conjugative factor TraI from Salmonella pCU1 and reveal a previously uncharacterized C-terminal functional domain that uncouples ATP hydrolysis from strand separation activity.
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18
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Kobayashi M, Kinjo T, Koseki Y, Bourne CR, Barrow WW, Aoki S. Identification of novel potential antibiotics against Staphylococcus using structure-based drug screening targeting dihydrofolate reductase. J Chem Inf Model 2014; 54:1242-53. [PMID: 24655350 PMCID: PMC4334291 DOI: 10.1021/ci400686d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
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The emergence of multidrug-resistant Staphylococcus aureus (S. aureus) makes
the treatment of infectious diseases
in hospitals more difficult and increases the mortality of the patients.
In this study, we attempted to identify novel potent antibiotic candidate
compounds against S. aureus dihydrofolate reductase
(saDHFR). We performed three-step in silico structure-based
drug screening (SBDS) based on the crystal structure of saDHFR using
a 154,118 chemical compound library. We subsequently evaluated whether
candidate chemical compounds exhibited inhibitory effects on the growth
of the model bacterium: Staphylococcus epidermidis (S. epidermidis). The compound KB1 showed a strong
inhibitory effect on the growth of S. epidermidis. Moreover, we rescreened chemical structures similar to KB1 from
a 461,397 chemical compound library. Three of the four KB1 analogs
(KBS1, KBS3, and KBS4) showed inhibitory effects on the growth of S. epidermidis and enzyme inhibitory effects on saDHFR.
We performed structure–activity relationship (SAR) analysis
of active chemical compounds and observed a correlative relationship
among the IC50 values, interaction residues, and structure
scaffolds. In addition, the active chemical compounds (KB1, KBS3,
and KBS4) had no inhibitory effects on the growth of model enterobacteria
(E. coli BL21 and JM109 strains) and no toxic effects
on cultured mammalian cells (MDCK cells). Results obtained from Protein
Ligand Interaction Fingerprint (PLIF) and Ligand Interaction (LI)
analyses suggested that all of the active compounds exhibited potential
inhibitory effects on mutated saDHFR of the drug-resistant strains.
The structural and experimental information concerning these novel
chemical compounds will likely contribute to the development of new
antibiotics for both wild-type and drug-resistant S. aureus.
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Affiliation(s)
- Maiko Kobayashi
- Department of Bioscience and Bioinformatics, Graduate School of Computer Science and Systems Engineering, Kyushu Institute of Technology , 680-4 Kawazu, Iizuka-shi, Fukuoka 820-8502, Japan
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19
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Li B, Pai R, Aiello D, Di M, Barnes MH, Peet NP, Bowlin TL, Moir DT. Optimization of a novel potent and selective bacterial DNA helicase inhibitor scaffold from a high throughput screening hit. Bioorg Med Chem Lett 2013; 23:3481-6. [PMID: 23664213 DOI: 10.1016/j.bmcl.2013.04.055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/12/2013] [Accepted: 04/22/2013] [Indexed: 01/15/2023]
Abstract
Benzobisthiazole derivatives were identified as novel helicase inhibitors through high throughput screening against purified Staphylococcus aureus (Sa) and Bacillus anthracis (Ba) replicative helicases. Chemical optimization has produced compound 59 with nanomolar potency against the DNA duplex strand unwinding activities of both B. anthracis and S. aureus helicases. Selectivity index (SI=CC50/IC50) values for 59 were greater than 500. Kinetic studies demonstrated that the benzobisthiazole-based bacterial helicase inhibitors act competitively with the DNA substrate. Therefore, benzobisthiazole helicase inhibitors represent a promising new scaffold for evaluation as antibacterial agents.
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Affiliation(s)
- Bing Li
- Microbiotix Inc., One Innovation Drive, Worcester, MA 01605, USA.
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20
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Shadrick WR, Ndjomou J, Kolli R, Mukherjee S, Hanson AM, Frick DN. Discovering new medicines targeting helicases: challenges and recent progress. ACTA ACUST UNITED AC 2013; 18:761-81. [PMID: 23536547 PMCID: PMC4427233 DOI: 10.1177/1087057113482586] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Helicases are ubiquitous motor proteins that separate and/or rearrange nucleic acid duplexes in reactions fueled by adenosine triphosphate (ATP) hydrolysis. Helicases encoded by bacteria, viruses, and human cells are widely studied targets for new antiviral, antibiotic, and anticancer drugs. This review summarizes the biochemistry of frequently targeted helicases. These proteins include viral enzymes from herpes simplex virus, papillomaviruses, polyomaviruses, coronaviruses, the hepatitis C virus, and various flaviviruses. Bacterial targets examined include DnaB-like and RecBCD-like helicases. The human DEAD-box protein DDX3 is the cellular antiviral target discussed, and cellular anticancer drug targets discussed are the human RecQ-like helicases and eIF4A. We also review assays used for helicase inhibitor discovery and the most promising and common helicase inhibitor chemotypes, such as nucleotide analogues, polyphenyls, metal ion chelators, flavones, polycyclic aromatic polymers, coumarins, and various DNA binding pharmacophores. Also discussed are common complications encountered while searching for potent helicase inhibitors and possible solutions for these problems.
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Affiliation(s)
- William R Shadrick
- Department of Chemistry & Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
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21
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Li B, Pai R, Di M, Aiello D, Barnes MH, Butler MM, Tashjian TF, Peet NP, Bowlin TL, Moir DT. Coumarin-based inhibitors of Bacillus anthracis and Staphylococcus aureus replicative DNA helicase: chemical optimization, biological evaluation, and antibacterial activities. J Med Chem 2012; 55:10896-908. [PMID: 23231076 DOI: 10.1021/jm300922h] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The increasing prevalence of drug-resistant bacterial infections demands the development of new antibacterials that are not subject to existing mechanisms of resistance. Previously, we described coumarin-based inhibitors of an underexploited bacterial target, namely the replicative helicase. Here we report the synthesis and evaluation of optimized coumarin-based inhibitors with 9-18-fold increased potency against Staphylococcus aureus (Sa) and Bacillus anthracis (Ba) helicases. Compounds 20 and 22 provided the best potency, with IC(50) values of 3 and 1 μM, respectively, against the DNA duplex strand-unwinding activities of both B. anthracis and S. aureus helicases without affecting the single strand DNA-stimulated ATPase activity. Selectivity index (SI = CC(50)/MIC) values against S. aureus and B. anthracis for compound 20 were 33 and 66 and for compound 22 were 20 and 40, respectively. In addition, compounds 20 and 22 demonstrated potent antibacterial activity against multiple ciprofloxacin-resistant MRSA strains, with MIC values ranging between 0.5 and 4.2 μg/mL.
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Affiliation(s)
- Bing Li
- Microbiotix Inc., One Innovation Drive, Worcester, Massachusetts 01605, USA.
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22
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Biswas-Fiss EE, Kukiratirat J, Biswas SB. Thermodynamic analysis of DNA binding by a Bacillus single stranded DNA binding protein. BMC BIOCHEMISTRY 2012; 13:10. [PMID: 22698072 PMCID: PMC3464605 DOI: 10.1186/1471-2091-13-10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 05/21/2012] [Indexed: 12/31/2022]
Abstract
BACKGROUND Single-stranded DNA binding proteins (SSB) are essential for DNA replication, repair, and recombination in all organisms. SSB works in concert with a variety of DNA metabolizing enzymes such as DNA polymerase. RESULTS We have cloned and purified SSB from Bacillus anthracis (SSB(BA)). In the absence of DNA, at concentrations ≤100 μg/ml, SSB(BA) did not form a stable tetramer and appeared to resemble bacteriophage T4 gene 32 protein. Fluorescence anisotropy studies demonstrated that SSB(BA) bound ssDNA with high affinity comparable to other prokaryotic SSBs. Thermodynamic analysis indicated both hydrophobic and ionic contributions to ssDNA binding. FRET analysis of oligo(dT)(70) binding suggested that SSB(BA) forms a tetrameric assembly upon ssDNA binding. This report provides evidence of a bacterial SSB that utilizes a novel mechanism for DNA binding through the formation of a transient tetrameric structure. CONCLUSIONS Unlike other prokaryotic SSB proteins, SSB(BA) from Bacillus anthracis appeared to be monomeric at concentrations ≤100 μg/ml as determined by SE-HPLC. SSB(BA) retained its ability to bind ssDNA with very high affinity, comparable to SSB proteins which are tetrameric. In the presence of a long ssDNA template, SSB(BA) appears to form a transient tetrameric structure. Its unique structure appears to be due to the cumulative effect of multiple key amino acid changes in its sequence during evolution, leading to perturbation of stable dimer and tetramer formation. The structural features of SSB(BA) could promote facile assembly and disassembly of the protein-DNA complex required in processes such as DNA replication.
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Affiliation(s)
- Esther E Biswas-Fiss
- Department of Molecular Biology, School of Osteopathic Medicine & Graduate School of Biomedical Sciences, University of Medicine & Dentistry of New Jersey, Stratford, NJ 08084, USA.
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23
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Tomašić T, Peterlin Mašič L. Rhodanine as a scaffold in drug discovery: a critical review of its biological activities and mechanisms of target modulation. Expert Opin Drug Discov 2012; 7:549-60. [PMID: 22607309 DOI: 10.1517/17460441.2012.688743] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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24
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Amundsen SK, Spicer T, Karabulut AC, Londoño LM, Eberhart C, Fernandez Vega V, Bannister TD, Hodder P, Smith GR. Small-molecule inhibitors of bacterial AddAB and RecBCD helicase-nuclease DNA repair enzymes. ACS Chem Biol 2012; 7:879-91. [PMID: 22443934 DOI: 10.1021/cb300018x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The AddAB and RecBCD helicase-nucleases are related enzymes prevalent among bacteria but not eukaryotes and are instrumental in the repair of DNA double-strand breaks and in genetic recombination. Although these enzymes have been extensively studied both genetically and biochemically, inhibitors specific for this class of enzymes have not been reported. We developed a high-throughput screen based on the ability of phage T4 gene 2 mutants to grow in Escherichia coli only if the host RecBCD enzyme, or a related helicase-nuclease, is inhibited or genetically inactivated. We optimized this screen for use in 1536-well plates and screened 326,100 small molecules in the NIH molecular libraries sample collection for inhibitors of the Helicobacter pylori AddAB enzyme expressed in an E. coli recBCD deletion strain. Secondary screening used assays with cells expressing AddAB or RecBCD and a viability assay that measured the effect of compounds on cell growth without phage infection. From this screening campaign, 12 compounds exhibiting efficacy and selectivity were tested for inhibition of purified AddAB and RecBCD helicase and nuclease activities and in cell-based assays for recombination; seven were active in the 0.1-50 μM range in one or another assay. Compounds structurally related to two of these were similarly tested, and three were active in the 0.1-50 μM range. These compounds should be useful in further enzymatic, genetic, and physiological studies of these enzymes, both purified and in cells. They may also lead to useful antibacterial agents, since this class of enzymes is needed for successful bacterial infection of mammals.
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Affiliation(s)
- Susan K. Amundsen
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington
98109, United States
| | - Timothy Spicer
- Scripps
Research Institute Molecular
Screening Center, Lead Identification Division, Translational Research Institute, Jupiter, Florida 33458, United States
| | - Ahmet C. Karabulut
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington
98109, United States
| | - Luz Marina Londoño
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington
98109, United States
| | - Christina Eberhart
- Scripps
Research Institute Molecular
Screening Center, Lead Identification Division, Translational Research Institute, Jupiter, Florida 33458, United States
| | - Virneliz Fernandez Vega
- Scripps
Research Institute Molecular
Screening Center, Lead Identification Division, Translational Research Institute, Jupiter, Florida 33458, United States
| | - Thomas D. Bannister
- Scripps Research Institute Department
of Chemistry, Translational Research Institute, Jupiter, Florida 33458, United States
| | - Peter Hodder
- Scripps
Research Institute Molecular
Screening Center, Lead Identification Division, Translational Research Institute, Jupiter, Florida 33458, United States
- Department of Molecular Therapeutics, Scripps Florida, Jupiter, Florida 33458, United States
| | - Gerald R. Smith
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington
98109, United States
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25
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Beierlein JM, Anderson AC. New developments in vaccines, inhibitors of anthrax toxins, and antibiotic therapeutics for Bacillus anthracis. Curr Med Chem 2012; 18:5083-94. [PMID: 22050756 DOI: 10.2174/092986711797636036] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 09/07/2011] [Accepted: 09/09/2011] [Indexed: 01/28/2023]
Abstract
Bacillus anthracis, the causative agent responsible for anthrax infections, poses a significant biodefense threat. There is a high mortality rate associated with untreated anthrax infections; specifically, inhalation anthrax is a particularly virulent form of infection with mortality rates close to 100%, even with aggressive treatment. Currently, a vaccine is not available to the general public and few antibiotics have been approved by the FDA for the treatment of inhalation anthrax. With the threat of natural or engineered bacterial resistance to antibiotics and the limited population for whom the current drugs are approved, there is a clear need for more effective treatments against this deadly infection. A comprehensive review of current research in drug discovery is presented in this article, including efforts to improve the purity and stability of vaccines, design inhibitors targeting the anthrax toxins, and identify inhibitors of novel enzyme targets. High resolution structural information for the anthrax toxins and several essential metabolic enzymes has played a significant role in aiding the structure-based design of potent and selective antibiotics.
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Affiliation(s)
- J M Beierlein
- Dept. Pharmaceutical Sciences, University of Connecticut, 69 N. Eagleville Rd., Storrs, CT 06269, USA
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26
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Sanyal G, Doig P. Bacterial DNA replication enzymes as targets for antibacterial drug discovery. Expert Opin Drug Discov 2012; 7:327-39. [PMID: 22458504 DOI: 10.1517/17460441.2012.660478] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION The bacterial replisome is composed of a large number of enzymes, which work in exquisite coordination to accomplish chromosomal replication. Effective inhibition inside the bacterial cell of any of the 'essential' enzymes of the DNA replication pathway should be detrimental to cell survival. AREAS COVERED This review covers DNA replication enzymes that have been shown to have a potential for delivering antibacterial compounds or drug candidates including: type II topoisomerases, a clinically validated target family, and DNA ligase, which has yielded inhibitors with in vivo efficacy. A few of the 'replisome' enzymes that are structurally and functionally well characterized and have been subjects of antibacterial discovery efforts are also discussed. EXPERT OPINION Identification of several essential genes in the bacterial replication pathway raised hopes that targeting these gene products would lead to novel antibacterials. However, none of these novel, single gene targets have delivered antibacterial drug candidates into clinical trials. This lack of productivity may be due to the target properties and inhibitor identification approaches employed. For DNA primase, DNA helicase and other replisome targets, with the exception of DNA ligase, the exploitation of structure for lead generation has not been tested to the same extent that it has for DNA gyrase. Utilization of structural information should be considered to augment HTS efforts and initiate fragment-based lead generation. The complex protein-protein interactions involved in regulation of replication may explain why biochemical approaches have been less productive for some replisome targets than more independently functioning targets such as DNA ligase or DNA gyrase.
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Affiliation(s)
- Gautam Sanyal
- Infection Innovative Medicines Unit, AstraZeneca R&D Boston, 35 Gatehouse Dr, Waltham, MA 02451, USA.
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27
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Calderano SG, de Melo Godoy PD, da Cunha JPC, Elias MC. Trypanosome prereplication machinery: a potential new target for an old problem. Enzyme Res 2011; 2011:518258. [PMID: 21755041 PMCID: PMC3112515 DOI: 10.4061/2011/518258] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 03/16/2011] [Accepted: 03/30/2011] [Indexed: 12/17/2022] Open
Abstract
Approximately ten million people suffer from Chagas disease worldwide, caused by Trypanosoma cruzi, with the disease burden predominately focused in Latin America. Sleeping sickness is another serious health problem, caused by Trypanosoma brucei, especially in sub-Saharan countries. Unfortunately, the drugs currently available to treat these diseases have toxic effects and are not effective against all disease phases or parasite strains. Therefore, there is a clear need for the development of novel drugs and drug targets to treat these diseases. We propose the trypanosome prereplication machinery component, Orc1/Cdc6, as a potential target for drug development. In trypanosomes, Orc1/Cdc6 is involved in nuclear DNA replication, and, despite its involvement in such a conserved process, Orc1/Cdc6 is distinct from mammalian Orc1 and Cdc6 proteins. Moreover, RNAi-mediated silencing of trypanosome Orc1/Cdc6 expression in T. brucei decreased cell survival, indicating that Orc1/Cdc6 is critical for trypanosome survival.
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Affiliation(s)
- Simone Guedes Calderano
- Laboratório Especial de Toxinologia Aplicada (LETA) Center for Applied Toxinology (CAT/CEPID), Instituto Butantan, Avenida Vital Brasil 1500, 05503-000 São Paulo, SP, Brazil
| | - Patricia Diogo de Melo Godoy
- Laboratório Especial de Toxinologia Aplicada (LETA) Center for Applied Toxinology (CAT/CEPID), Instituto Butantan, Avenida Vital Brasil 1500, 05503-000 São Paulo, SP, Brazil
| | - Julia Pinheiro Chagas da Cunha
- Laboratório Especial de Toxinologia Aplicada (LETA) Center for Applied Toxinology (CAT/CEPID), Instituto Butantan, Avenida Vital Brasil 1500, 05503-000 São Paulo, SP, Brazil
| | - Maria Carolina Elias
- Laboratório Especial de Toxinologia Aplicada (LETA) Center for Applied Toxinology (CAT/CEPID), Instituto Butantan, Avenida Vital Brasil 1500, 05503-000 São Paulo, SP, Brazil
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28
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Nesterova IV, Bennett CA, Erdem SS, Hammer RP, Deininger PL, Soper SA. Near-IR single fluorophore quenching system based on phthalocyanine (Pc) aggregation and its application for monitoring inhibitor/activator action on a therapeutic target: L1-EN. Analyst 2011; 136:1103-5. [PMID: 21221467 DOI: 10.1039/c0an00782j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Controlled H-aggregation of single Pc-labeled oligonucleotides is utilized as a fluorescence quenching system to discern changes in enzyme activity for the discovery of inhibitors for Long Interspersed Element 1 endonuclease (L1-EN), which is involved in genome instability and implicated in many different diseases.
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Affiliation(s)
- Irina V Nesterova
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
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