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Dilip H, Thiruvenkatam V, Kirubakaran S. Studies on Methylpyrazole-Substituted Benzimidazoles to Target Helicobacter pylori Infection through HpIMPDH Inhibition. ACS Infect Dis 2024; 10:2262-2275. [PMID: 38787329 DOI: 10.1021/acsinfecdis.4c00228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The prevalence of Helicobacter pylori infection has been increasing rapidly due to the genetic heterogeneity and antibacterial resistance shown by the bacteria, affecting over 50% of the world population and over 80% of the Indian population, in particular. In this regard, novel drug targets are currently being explored, one of which is the crucial metabolic enzyme inosine-5'-monophosphate dehydrogenase (IMPDH) involved in the de novo nucleotide biosynthesis pathway, in order to combat the infection and devise efficient therapeutic strategies. The present study reports the development of methylpyrazole-substituted benzimidazoles as small molecule inhibitors of H. pylori IMPDH with a nanomolar range of enzyme inhibition. A set of 19 small molecules have been designed, synthesized, and further evaluated for their inhibitory potential against H. pylori IMPDH using in silico, in vitro, biochemical, and biophysical techniques. Compound 7j was found to inhibit H. pylori IMPDH with an IC50 value of 0.095 ± 0.023 μM, which is close to 1.5-fold increase in the inhibitory activity, in comparison to the previously reported benzimidazole-based hit C91. Moreover, kinetic characterization has provided significant insights into the uncompetitive inhibition shown by these small molecules on H. pylori IMPDH, thus providing details about the enzyme inhibition mechanism. In conclusion, methylpyrazole-based small molecules indicate a promising path to develop cheap and bioavailable drugs to efficiently treat H. pylori infection in the coming years, in comparison to the currently available therapy.
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Affiliation(s)
- Haritha Dilip
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat 382055, India
| | - Vijay Thiruvenkatam
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat 382055, India
| | - Sivapriya Kirubakaran
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat 382055, India
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2
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Lü Z, Dai X, Xu J, Liu Z, Guo Y, Gao Z, Meng F. Medicinal chemistry strategies toward broad-spectrum antiviral agents to prevent next pandemics. Eur J Med Chem 2024; 271:116442. [PMID: 38685143 DOI: 10.1016/j.ejmech.2024.116442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 04/02/2024] [Accepted: 04/19/2024] [Indexed: 05/02/2024]
Abstract
The pandemic and tremendous impact of severe acute respiratory syndrome coronavirus 2 alert us, despite great achievements in prevention and control of infectious diseases, we still lack universal and powerful antiviral strategies to rapidly respond to the potential threat of serious infectious disease. Various highly contagious and pathogenic viruses, as well as other unknown viruses may appear or reappear in human society at any time, causing a catastrophic epidemic. Developing broad-spectrum antiviral drugs with high security and efficiency is of great significance for timely meeting public health emergency and protecting the lives and health of the people. Hence, in this review, we summarized diverse broad-spectrum antiviral targets and corresponding agents from a medicinal chemistry prospective, compared the pharmacological advantages and disadvantages of different targets, listed representative agents, showed their structures, pharmacodynamics and pharmacokinetics characteristics, and conducted a critical discussion on their development potential, in the hope of providing up-to-date guidance for the development of broad-spectrum antivirals and perspectives for applications of antiviral therapy.
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Affiliation(s)
- Zirui Lü
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
| | - Xiandong Dai
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
| | - Jianjie Xu
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
| | - Zhenming Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, China
| | - Yongbiao Guo
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
| | - Zhenhua Gao
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
| | - Fanhua Meng
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China.
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Kesavan LR, Kamalan BC, Sivanandan S. Targeting human inosine 5' monophosphate dehydrogenase type 2 for anti-dengue lead identification - a computational approach. J Biomol Struct Dyn 2024:1-15. [PMID: 38517251 DOI: 10.1080/07391102.2024.2331094] [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: 11/02/2023] [Accepted: 03/10/2024] [Indexed: 03/23/2024]
Abstract
Dengue is a rapidly evolving arboviral disease that mainly affects tropical and subtropical regions of the world. The lack of therapeutic drugs and effective vaccines suggests that further resources need to be investigated. The effectiveness of the existing dengue vaccine is improbable as its efficacy depends on prior exposure to the dengue virus(DENV). Although the mechanism underlying the action of bioactive compounds to limit viral replication is less studied and still needs to be further explored, medicinal plants are excellent alternatives to combat DENV infection. In the current study, an in silico screening of phytochemicals from Annona reticulata Linn. against human Impdh2 was performed using Autodock Vina. Daucosterol (-9.0 kcal/mol) and Kaurenoic acid (-8.5 kcal/mol) were chosen as the top hits based on molecular interaction analysis. The hits were further exposed to pharmacokinetics and toxicity properties to determine their drug-like parameters. Molecular dynamics simulation studies of the Impdh2-top hits were carried out to investigate their kinetic behaviour and structural stabilities. The binding free energies of the Impdh2-hit complexes were determined using MM-PBSA analysis. According to the overall conclusions of the study, Daucosterol showed good binding affinity and high structural stability to the binding site residues of the target, therefore it is recommended as a lead compound against dengue.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Lekshmi Radha Kesavan
- Biotechnology and Bioinformatics Division, Saraswathy Thangavelu Extension Centre, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, A Research Centre of University of Kerala, Thiruvananthapuram, India
| | - Biju Charuvil Kamalan
- Biotechnology and Bioinformatics Division, Saraswathy Thangavelu Extension Centre, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, A Research Centre of University of Kerala, Thiruvananthapuram, India
| | - Sreekumar Sivanandan
- Biotechnology and Bioinformatics Division, Saraswathy Thangavelu Extension Centre, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, A Research Centre of University of Kerala, Thiruvananthapuram, India
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Zhu M, Wu N, Zhong J, Chen C, Liu W, Ren Y, Wang X, Jin H. N 6-methyladenosine modification of the mRNA for a key gene in purine nucleotide metabolism regulates virus proliferation in an insect vector. Cell Rep 2024; 43:113821. [PMID: 38368611 DOI: 10.1016/j.celrep.2024.113821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/10/2024] [Accepted: 02/02/2024] [Indexed: 02/20/2024] Open
Abstract
The titer of viruses that persist and propagate in their insect vector must be high enough for transmission yet not harm the insect, but the mechanism of this dynamic balance is unclear. Here, expression of inosine monophosphate dehydrogenase (LsIMPDH), a rate-limiting enzyme for guanosine triphosphate (GTP) synthesis, is shown to be downregulated by increased levels of N6-methyladenosine (m6A) on LsIMPDH mRNA in rice stripe virus (RSV)-infected small brown planthoppers (SBPHs; Laodelphax striatellus), the RSV vector, which decreases GTP content, thus limiting viral proliferation. Moreover, planthopper methyltransferase-like protein 3 (LsMETTL3) and m6A reader protein LsYTHDF3 are found to catalyze and recognize the m6A on LsIMPDH mRNA, respectively, and cooperate in destabilizing LsIMPDH transcripts. Co-silencing assays show that negative regulation of viral proliferation by both LsMETTL3 and LsYTHDF3 is partially dependent on LsIMPDH. This distinct mechanism limits virus replication in an insect vector, providing a potential gene target to block viral transmission.
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Affiliation(s)
- Mengjie Zhu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Nan Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Jiayi Zhong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Chen Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wenwen Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yingdang Ren
- Institute of Plant Protection, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Xifeng Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Huaibing Jin
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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Hernández-Gómez A, Irisarri I, Fernández-Justel D, Peláez R, Jiménez A, Revuelta JL, Balsera M, Buey RM. GuaB3, an overlooked enzyme in cyanobacteria's toolbox that sheds light on IMP dehydrogenase evolution. Structure 2023; 31:1526-1534.e4. [PMID: 37875114 DOI: 10.1016/j.str.2023.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/05/2023] [Accepted: 09/28/2023] [Indexed: 10/26/2023]
Abstract
IMP dehydrogenase and GMP reductase are enzymes from the same protein family with analogous structures and catalytic mechanisms that have gained attention because of their essential roles in nucleotide metabolism and as potential drug targets. This study focusses on GuaB3, a less-explored enzyme within this family. Phylogenetic analysis uncovers GuaB3's independent evolution from other members of the family and it predominantly occurs in Cyanobacteria. Within this group, GuaB3 functions as a unique IMP dehydrogenase, while its counterpart in Actinobacteria has a yet unknown function. Synechocystis sp. PCC6803 GuaB3 structures demonstrate differences in the active site compared to canonical IMP dehydrogenases, despite shared catalytic mechanisms. These findings highlight the essential role of GuaB3 in Cyanobacteria, provide insights into the diversity and evolution of the IMP dehydrogenase protein family, and reveal a distinctive characteristic in nucleotide metabolism, potentially aiding in combating harmful cyanobacterial blooms-a growing concern for humans and wildlife.
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Affiliation(s)
- Alejandro Hernández-Gómez
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - Iker Irisarri
- Section Phylogenomics, Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change (LIB), Museum of Nature Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
| | - David Fernández-Justel
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - Rafael Peláez
- Laboratorio de Química Orgánica y Farmacéutica, Dpto. Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - Alberto Jiménez
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - José Luis Revuelta
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - Mónica Balsera
- Department Abiotic Stress, Instituto de Recursos Naturales y Agrobiología (IRNASA-CSIC), Cordel de Merinas 40-52, 37008 Salamanca, Spain
| | - Rubén M Buey
- Metabolic Engineering Group, Dpto. Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007 Salamanca, Spain.
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Gao LJ, Lin Y, De Jonghe S, Waer M, Herdewijn P. Synthesis of mizoribine prodrugs and their in vivo evaluation as immunosuppressive agents. Bioorg Med Chem Lett 2023; 95:129490. [PMID: 37770001 DOI: 10.1016/j.bmcl.2023.129490] [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: 08/07/2023] [Revised: 09/12/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Mizoribine is a well-known immunosuppressive drug, based on a nucleoside scaffold, that targets inosine-monophosphate dehydrogenase (IMPDH). In an effort to increase its in vivo efficacy, three different types of prodrugs (a phosphoramidate prodrug, a lipophilic ester derivative and an amino acid conjugate) were prepared. Screening of these prodrugs in a rapid whole blood assay revealed that the two ester-based mizoribine prodrugs potently inhibited interleukin 2 secretion. Moreover, these prodrugs were able to prolong graft survival, when evaluated in a mouse model of cardiac allograft transplantation. Strikingly, a combination therapy of these mizoribine prodrugs with tacrolimus had a synergistic in vivo effect.
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Affiliation(s)
- Ling-Jie Gao
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Laboratory of Medicinal Chemistry, Herestraat 49, Box 1030, 3000 Leuven, Belgium
| | - Yuan Lin
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Molecular Immunology, Herestraat 49, Box 1042, 3000 Leuven, Belgium
| | - Steven De Jonghe
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, Box 1043, 3000 Leuven, Belgium
| | - Mark Waer
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Molecular Immunology, Herestraat 49, Box 1042, 3000 Leuven, Belgium
| | - Piet Herdewijn
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Laboratory of Medicinal Chemistry, Herestraat 49, Box 1030, 3000 Leuven, Belgium.
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7
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Gaiya DD, Muhammad A, Aimola IA, Udu SK, Balarabe SA, Auta R, Ekpa E, Sheyin A. Potential of Onchocerca ochengi inosine-5'-monophosphate dehydrogenase (IMPDH) and guanosine-5'-monophosphate oxidoreductase (GMPR) as druggable and vaccine candidates: immunoinformatics screening. J Biomol Struct Dyn 2023; 41:14832-14848. [PMID: 36866624 DOI: 10.1080/07391102.2023.2184171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 02/18/2023] [Indexed: 03/04/2023]
Abstract
Onchocerciasis is a vector-borne disease caused by the filarial nematode Onchocerca volvulus, which is responsible for most of the visual impairments recorded in Africa, Asia and the Americas. It is known that O. volvulus has similar molecular and biological characteristics as Onchocerca ochengi in cattle. This study was designed to screen for immunogenic epitopes and binding pockets of O. ochengi IMPDH and GMPR ligands using immunoinformatic approaches. In this study, a total of 23 B cell epitopes for IMPDH and 7 B cell epitopes for GMPR were predicted using ABCpred tool, Bepipred 2.0 and Kolaskar and Tongaonkar methods. The CD4+ Th computational results showed 16 antigenic epitopes from IMPDH with strong binding affinity for DRB1_0301, DRB3_0101, DRB1_0103 and DRB1_1501 MHC II alleles while 8 antigenic epitopes from GMPR were predicted to bind DRB1_0101 and DRB1_0401 MHC II alleles, respectively. For the CD8+ CTLs analysis, 8 antigenic epitopes from IMPDH showed strong binding affinity to human leukocyte antigen HLA-A*26:01, HLA-A*03:01, HLA-A*24:02 and HLA-A*01:01 MHC I alleles while 2 antigenic epitopes from GMPR showed strong binding affinity to HLA-A*01:01 allele, respectively. The immunogenic B cell and T cell epitopes were further evaluated for antigenicity, non-alllergernicity, toxicity, IFN-gamma, IL4 and IL10. The docking score revealed favorable binding free energy with IMP and MYD scoring the highest binding affinity at -6.6 kcal/mol with IMPDH and -8.3 kcal/mol with GMPR. This study provides valuable insight on IMPDH and GMPR as potential drug targets and for the development of multiple epitope vaccine candidates.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Daniel Danladi Gaiya
- Biology Unit, Faculty of Science, Air Force Institute of Technology, Nigerian Air Force Base, Kawo, Kaduna State, Nigeria
| | - Aliyu Muhammad
- Department of Biochemistry, Faculty of Life Sciences, Ahmadu Bello University, Samaru Zaria, Kaduna State, Nigeria
| | - Idowu Asegame Aimola
- Department of Biochemistry, Faculty of Life Sciences, Ahmadu Bello University, Samaru Zaria, Kaduna State, Nigeria
| | - Stella Kuyet Udu
- Biology Unit, Faculty of Science, Air Force Institute of Technology, Nigerian Air Force Base, Kawo, Kaduna State, Nigeria
| | - Sallau Abdullahi Balarabe
- Department of Biochemistry, Faculty of Life Sciences, Ahmadu Bello University, Samaru Zaria, Kaduna State, Nigeria
| | - Richard Auta
- Department of Biochemistry, Faculty of Science, Kaduna State University, Kaduna, Kaduna State, Nigeria
| | - Emmanuel Ekpa
- Biology Unit, Faculty of Science, Air Force Institute of Technology, Nigerian Air Force Base, Kawo, Kaduna State, Nigeria
| | - Abraham Sheyin
- Department of Biochemistry, Faculty of Life Sciences, Ahmadu Bello University, Samaru Zaria, Kaduna State, Nigeria
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Fragment-Based Lead Discovery Strategies in Antimicrobial Drug Discovery. Antibiotics (Basel) 2023; 12:antibiotics12020315. [PMID: 36830226 PMCID: PMC9951956 DOI: 10.3390/antibiotics12020315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Fragment-based lead discovery (FBLD) is a powerful application for developing ligands as modulators of disease targets. This approach strategy involves identification of interactions between low-molecular weight compounds (100-300 Da) and their putative targets, often with low affinity (KD ~0.1-1 mM) interactions. The focus of this screening methodology is to optimize and streamline identification of fragments with higher ligand efficiency (LE) than typical high-throughput screening. The focus of this review is on the last half decade of fragment-based drug discovery strategies that have been used for antimicrobial drug discovery.
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Dahmer BR, Ethur EM, Timmers LFSM. Discovery of new inhibitors of Mycobacterium tuberculosis EPSP synthase - A computational study. J Mol Graph Model 2023; 121:108404. [PMID: 36907015 DOI: 10.1016/j.jmgm.2023.108404] [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: 04/14/2022] [Revised: 10/23/2022] [Accepted: 01/08/2023] [Indexed: 01/12/2023]
Abstract
Tuberculosis (TB) is a highly infectious disease caused by the pathogen Mycobacterium tuberculosis (Mtb). EPSP Synthase (MtEPSPS), the enzyme responsible for the sixth step of the shikimate pathway, is a potential target for the development of new drugs for the treatment of TB, as it is essential in mycobacteria but absent in humans. In this work, we performed virtual screening using sets of molecules from two databases and three crystallographic structures of MtEPSPS. The initial hits obtained from molecular docking were filtered based on predicted binding affinity and interactions with binding site residues. Subsequently, molecular dynamics simulations were carried out to analyze the stability of protein-ligand complexes. We have found that MtEPSPS forms stable interactions with several candidates, including already approved pharmaceutical drugs such as Conivaptan and Ribavirin monophosphate. In particular, Conivaptan had the highest estimated binding affinity with the open conformation of the enzyme. The complex formed between MtEPSPS and Ribavirin monophosphate was also energetically stable as shown by RMSD, Rg and FEL analyses, and the ligand was stabilized by hydrogen bonds with important residues of the binding site. The findings reported in this work could serve as the basis of promising scaffolds for the discovery, design, and development of new anti-TB drugs.
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Affiliation(s)
- Bruno Rampanelli Dahmer
- University of Taquari Valley - Univates, Avenida Avelino Tallini, 171, CEP, 95914-014, Lajeado, RS, Brazil; Programa de Pós-Graduação em Biotecnologia - PPGBiotec, University of Taquari Valley - Univates, Avenida Avelino Tallini, 171, CEP, 95914-014, Lajeado, RS, Brazil
| | - Eduardo Miranda Ethur
- University of Taquari Valley - Univates, Avenida Avelino Tallini, 171, CEP, 95914-014, Lajeado, RS, Brazil; Programa de Pós-Graduação em Biotecnologia - PPGBiotec, University of Taquari Valley - Univates, Avenida Avelino Tallini, 171, CEP, 95914-014, Lajeado, RS, Brazil
| | - Luis Fernando Saraiva Macedo Timmers
- University of Taquari Valley - Univates, Avenida Avelino Tallini, 171, CEP, 95914-014, Lajeado, RS, Brazil; Programa de Pós-Graduação em Biotecnologia - PPGBiotec, University of Taquari Valley - Univates, Avenida Avelino Tallini, 171, CEP, 95914-014, Lajeado, RS, Brazil; Programa de Pós-Graduação em Ciências Médicas - PPGCM, University of Taquari Valley - Univates, Avenida Avelino Tallini, 171, CEP, 95914-014, Lajeado, RS, Brazil.
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Yazdani M, Zamani J, Fatemi SSA. Identification of a potent dual-function inhibitor for hIMPDH isoforms by computer-aided drug discovery approaches. Front Pharmacol 2022; 13:977568. [PMID: 36386211 PMCID: PMC9643795 DOI: 10.3389/fphar.2022.977568] [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: 06/27/2022] [Accepted: 09/29/2022] [Indexed: 11/19/2023] Open
Abstract
Inosine monophosphate dehydrogenase (IMPDH) is a key enzyme in de novo biosynthesis of purine nucleotides. Due to this important role, it is a great target to drug discovery for a wide range of activities, especially immunosuppressant in heart and kidney transplantation. Both human IMPDH isoforms are expressed in stimulated lymphocytes. In addition to the side effects of existing drugs, previous studies have mainly focused on the type II isoform. In this study, virtual screening and computer-aided approaches were employed to identify potential drugs with simultaneous inhibitory effects on both human IMPDH isoforms. After Re-docking, Double-step docking, and identification of virtual hits based on the PLANTS scoring function, drug-likeness and ADME-Tox assessments of the topmost ligands were performed. Following further evaluation, the best ligand was selected and, in complex with both isoforms, simulated in monomeric and tetrameric forms using molecular dynamics to evaluate its stability and binding pattern. The results showed a potential drug candidate [(S)-N-(3-hydroxy-1-(4-hydroxyphenyl) propyl)-2-(3-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl) acetamide] with a high inhibitory effect on the two human IMPDH isoforms. This drug-like inhibitor could potentially serve as an immunosuppressant to prevent transplant rejection response by inhibiting B- and T-lymphocyte proliferation. In addition, its effect can be evaluated in various therapeutic targets in which IMPDH is known as a therapeutic target, especially in Covid-19 patients.
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Affiliation(s)
- Meysam Yazdani
- Department of Systems Biotechnology, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Javad Zamani
- Department of Plant Molecular Biotechnology, Institute of Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Seyed Safa-Ali Fatemi
- Department of Systems Biotechnology, Institute of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
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Inhibitors of Nucleotide Biosynthesis as Candidates for a Wide Spectrum of Antiviral Chemotherapy. Microorganisms 2022; 10:microorganisms10081631. [PMID: 36014049 PMCID: PMC9413629 DOI: 10.3390/microorganisms10081631] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 11/21/2022] Open
Abstract
Emerging and re-emerging viruses have been a challenge in public health in recent decades. Host-targeted antivirals (HTA) directed at cellular molecules or pathways involved in virus multiplication represent an interesting strategy to combat viruses presently lacking effective chemotherapy. HTA could provide a wide range of agents with inhibitory activity against current and future viruses that share similar host requirements and reduce the possible selection of antiviral-resistant variants. Nucleotide metabolism is one of the more exploited host metabolic pathways as a potential antiviral target for several human viruses. This review focuses on the antiviral properties of the inhibitors of pyrimidine and purine nucleotide biosynthesis, with an emphasis on the rate-limiting enzymes dihydroorotate dehydrogenase (DHODH) and inosine monophosphate dehydrogenase (IMPDH) for which there are old and new drugs active against a broad spectrum of pathogenic viruses.
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12
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Park CK, Horton NC. Structures, functions, and mechanisms of filament forming enzymes: a renaissance of enzyme filamentation. Biophys Rev 2019; 11:927-994. [PMID: 31734826 PMCID: PMC6874960 DOI: 10.1007/s12551-019-00602-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
Filament formation by non-cytoskeletal enzymes has been known for decades, yet only relatively recently has its wide-spread role in enzyme regulation and biology come to be appreciated. This comprehensive review summarizes what is known for each enzyme confirmed to form filamentous structures in vitro, and for the many that are known only to form large self-assemblies within cells. For some enzymes, studies describing both the in vitro filamentous structures and cellular self-assembly formation are also known and described. Special attention is paid to the detailed structures of each type of enzyme filament, as well as the roles the structures play in enzyme regulation and in biology. Where it is known or hypothesized, the advantages conferred by enzyme filamentation are reviewed. Finally, the similarities, differences, and comparison to the SgrAI endonuclease system are also highlighted.
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Affiliation(s)
- Chad K. Park
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
| | - Nancy C. Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
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13
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Trapero A, Pacitto A, Chan DSH, Abell C, Blundell TL, Ascher DB, Coyne AG. Covalent inactivation of Mycobacterium thermoresistibile inosine-5'-monophosphate dehydrogenase (IMPDH). Bioorg Med Chem Lett 2019; 30:126792. [PMID: 31757668 DOI: 10.1016/j.bmcl.2019.126792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 10/30/2019] [Indexed: 11/28/2022]
Abstract
Inosine-5'-monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme involved in nucleotide biosynthesis. Because of its critical role in purine biosynthesis, IMPDH is a drug design target for immunosuppressive, anticancer, antiviral and antimicrobial chemotherapy. In this study, we use mass spectrometry and X-ray crystallography to show that the inhibitor 6-Cl-purine ribotide forms a covalent adduct with the Cys-341 residue of Mycobacterium thermoresistibile IMPDH.
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Affiliation(s)
- Ana Trapero
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Angela Pacitto
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom
| | - Daniel Shiu-Hin Chan
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Chris Abell
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom.
| | - David B Ascher
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom; Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3052, Australia.
| | - Anthony G Coyne
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
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14
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Camici M, Garcia-Gil M, Pesi R, Allegrini S, Tozzi MG. Purine-Metabolising Enzymes and Apoptosis in Cancer. Cancers (Basel) 2019; 11:cancers11091354. [PMID: 31547393 PMCID: PMC6769685 DOI: 10.3390/cancers11091354] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/03/2019] [Accepted: 09/07/2019] [Indexed: 12/17/2022] Open
Abstract
The enzymes of both de novo and salvage pathways for purine nucleotide synthesis are regulated to meet the demand of nucleic acid precursors during proliferation. Among them, the salvage pathway enzymes seem to play the key role in replenishing the purine pool in dividing and tumour cells that require a greater amount of nucleotides. An imbalance in the purine pools is fundamental not only for preventing cell proliferation, but also, in many cases, to promote apoptosis. It is known that tumour cells harbour several mutations that might lead to defective apoptosis-inducing pathways, and this is probably at the basis of the initial expansion of the population of neoplastic cells. Therefore, knowledge of the molecular mechanisms that lead to apoptosis of tumoural cells is key to predicting the possible success of a drug treatment and planning more effective and focused therapies. In this review, we describe how the modulation of enzymes involved in purine metabolism in tumour cells may affect the apoptotic programme. The enzymes discussed are: ectosolic and cytosolic 5'-nucleotidases, purine nucleoside phosphorylase, adenosine deaminase, hypoxanthine-guanine phosphoribosyltransferase, and inosine-5'-monophosphate dehydrogenase, as well as recently described enzymes particularly expressed in tumour cells, such as deoxynucleoside triphosphate triphosphohydrolase and 7,8-dihydro-8-oxoguanine triphosphatase.
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Affiliation(s)
- Marcella Camici
- Dipartimento di Biologia, Unità di Biochimica, Via S. Zeno 51, 56127 Pisa, Italy.
| | - Mercedes Garcia-Gil
- Dipartimento di Biologia, Unità di Fisiologia Generale, Via S. Zeno 31, 56127 Pisa, Italy
| | - Rossana Pesi
- Dipartimento di Biologia, Unità di Biochimica, Via S. Zeno 51, 56127 Pisa, Italy
| | - Simone Allegrini
- Dipartimento di Biologia, Unità di Biochimica, Via S. Zeno 51, 56127 Pisa, Italy
| | - Maria Grazia Tozzi
- Dipartimento di Biologia, Unità di Biochimica, Via S. Zeno 51, 56127 Pisa, Italy
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15
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Shah CP, Kharkar PS. Discovery of novel human inosine 5'-monophosphate dehydrogenase 2 (hIMPDH2) inhibitors as potential anticancer agents. Eur J Med Chem 2018; 158:286-301. [PMID: 30223117 DOI: 10.1016/j.ejmech.2018.09.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 08/13/2018] [Accepted: 09/05/2018] [Indexed: 02/08/2023]
Abstract
The enzyme inosine 5'-monophosphate dehydrogenase (IMPDH) catalyzes an essential step in the de novo biosynthesis of guanine nucleotides, and thus regulates the guanine nucleotide pool required for cell proliferation. Of the two isoforms, human IMPDH type 2 (hIMPDH2) is a validated molecular target for potential immunosuppressive, antiviral and anticancer chemotherapy. In search of newer hIMPDH2 inhibitors as potential anticancer agents, three novel series (A: 5-aminoisobenzofuran-1(3H)-one, B: 3,4-dimethoxyaniline and C: benzo[d]-[1,3]dioxol-5-ylmethanamine) were synthesized and evaluated for in vitro and cell-based activities. A total of 37 molecules (29-65) were screened for their in vitro hIMPDH2 inhibition, with particular emphasis on establishing their structure-activity relationship (SAR) trends. Eight compounds (hits, 30, 31, 33-35, 37, 41 and 43) demonstrated significant enzyme inhibition (>70% @ 10 μM); especially the A series molecules were more potent than B series (<70% inhibition @ 10 μM), while C series members were found to be inactive. The hIMPDH2 IC50 values for the hits ranged from 0.36 to 7.38 μM. The hits displaying >80% hIMPDH2 inhibition (30, 33, 35, 41 and 43) were further assessed for their cytotoxic activity against cancer cell lines such as MDA-MB-231 (breast adenocarcinoma), DU145 (prostate carcinoma), U87 MG (glioblastoma astrocytoma) and a normal cell line, NIH-3T3 (mouse embryonic fibroblast) using MTT assay. Most of the compounds exhibited higher cellular potency against cancer cell lines and notably lower toxicity towards NIH-3T3 cells compared to mycophenolic acid (MPA), a prototypical hIMPDH2 inhibitor. Two of the series A hits (30 and 35) were evaluated in human peripheral blood mononuclear cells (hPBMC) assay and found to be better tolerated than MPA. The calculated/predicted molecular and physicochemical properties were satisfactory with reference to drug-likeness. The molecular docking studies clearly demonstrated crucial interactions of the hits with the cofactor-binding site of hIMPDH2, further providing critical information for refining the design strategy. The present study reports the design and discovery of structurally novel hIMPDH2 inhibitors as potential anticancer agents and provides a guide for further research on the development of safe and effective anticancer agents, especially against glioblastoma.
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Affiliation(s)
- Chetan P Shah
- Department of Pharmaceutical Chemistry, Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS, V. L. Mehta Road, Vile Parle (West), Mumbai, 400 056, India
| | - Prashant S Kharkar
- Department of Pharmaceutical Chemistry, Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS, V. L. Mehta Road, Vile Parle (West), Mumbai, 400 056, India.
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16
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Shah CP, Kharkar PS. Newer human inosine 5'-monophosphate dehydrogenase 2 (hIMPDH2) inhibitors as potential anticancer agents. J Enzyme Inhib Med Chem 2018; 33:972-977. [PMID: 29792360 PMCID: PMC6009919 DOI: 10.1080/14756366.2018.1474211] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Human inosine 5′-monophosphate dehydrogenase 2 (hIMPDH2), being an age-old target, has attracted attention recently for anticancer drug development. Mycophenolic acid (MPA), a well-known immunosuppressant drug, was used a lead structure to design and develop modestly potent and selective analogues. The steep structure–activity relationship (SAR) requirements of the lead molecule left little scope to synthesise newer analogues. Here, newer MPA amides were designed, synthesised and evaluated for hIMPDH2 inhibition and cellular efficacy in breast, prostate and glioblastoma cell lines. Few title compounds exhibited cellular activity profile better than MPA itself. The observed differences in the overall biological profile could be attributed to improved structural and physicochemical properties of the analogues over MPA. This is the first report of the activity of MPA derivatives in glioblastoma, the most aggressive brain cancer.
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Affiliation(s)
- Chetan P Shah
- a Department of Pharmaceutical Chemistry , SPP School of Pharmacy and Technology Management, SVKM's NMIMS , Mumbai , India
| | - Prashant S Kharkar
- a Department of Pharmaceutical Chemistry , SPP School of Pharmacy and Technology Management, SVKM's NMIMS , Mumbai , India
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17
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Trapero A, Pacitto A, Singh V, Sabbah M, Coyne AG, Mizrahi V, Blundell TL, Ascher DB, Abell C. Fragment-Based Approach to Targeting Inosine-5'-monophosphate Dehydrogenase (IMPDH) from Mycobacterium tuberculosis. J Med Chem 2018; 61:2806-2822. [PMID: 29547284 PMCID: PMC5900554 DOI: 10.1021/acs.jmedchem.7b01622] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
![]()
Tuberculosis (TB)
remains a major cause of mortality worldwide,
and improved treatments are needed to combat emergence of drug resistance.
Inosine 5′-monophosphate dehydrogenase (IMPDH), a crucial enzyme
required for de novo synthesis of guanine nucleotides,
is an attractive TB drug target. Herein, we describe the identification
of potent IMPDH inhibitors using fragment-based screening and structure-based
design techniques. Screening of a fragment library for Mycobacterium
thermoresistible (Mth) IMPDH ΔCBS
inhibitors identified a low affinity phenylimidazole derivative. X-ray
crystallography of the Mth IMPDH ΔCBS–IMP–inhibitor
complex revealed that two molecules of the fragment were bound in
the NAD binding pocket of IMPDH. Linking the two molecules of the
fragment afforded compounds with more than 1000-fold improvement in
IMPDH affinity over the initial fragment hit.
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Affiliation(s)
- Ana Trapero
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Angela Pacitto
- Department of Biochemistry , University of Cambridge , 80 Tennis Court Road , Cambridge CB2 1GA , United Kingdom
| | - Vinayak Singh
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine and Division of Medical Microbiology, Faculty of Health Sciences , University of Cape Town , Rondebosch 7701 , Cape Town , South Africa
| | - Mohamad Sabbah
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Anthony G Coyne
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Valerie Mizrahi
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit & DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine and Division of Medical Microbiology, Faculty of Health Sciences , University of Cape Town , Rondebosch 7701 , Cape Town , South Africa
| | - Tom L Blundell
- Department of Biochemistry , University of Cambridge , 80 Tennis Court Road , Cambridge CB2 1GA , United Kingdom
| | - David B Ascher
- Department of Biochemistry , University of Cambridge , 80 Tennis Court Road , Cambridge CB2 1GA , United Kingdom.,Department of Biochemistry and Molecular Biology, Bio21 Institute , University of Melbourne , 30 Flemington Road , Parkville , Victoria 3052 , Australia
| | - Chris Abell
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
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18
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Calise SJ, Purich DL, Nguyen T, Saleem DA, Krueger C, Yin JD, Chan EKL. 'Rod and ring' formation from IMP dehydrogenase is regulated through the one-carbon metabolic pathway. J Cell Sci 2016; 129:3042-52. [PMID: 27343244 DOI: 10.1242/jcs.183400] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 06/21/2016] [Indexed: 12/29/2022] Open
Abstract
'Rods and rings' (RRs) are conserved, non-membrane-bound intracellular polymeric structures composed, in part, of inosine monophosphate dehydrogenase (IMPDH), a key enzyme leading to GMP and GTP biosynthesis. RR formation is induced by IMPDH inhibitors as well as glutamine deprivation. They also form upon treatment of cells with glutamine synthetase inhibitors. We now report that depriving cells of serine and glycine promotes RR formation, and we have traced these effects to dihydrofolate reductase (DHFR) and serine hydroxymethyltransferase-2 (SHMT2), pivotal enzymes in one-carbon metabolism and nucleotide biosynthesis. RR assembly is likewise induced upon DHFR inhibition by methotrexate or aminopterin as well as siRNA-mediated knockdown of DHFR or SHMT2. Because RR assembly occurs when guanine nucleotide biosynthesis is inhibited, and because RRs rapidly disassemble after the addition of guanine nucleotide precursors, RR formation might be an adaptive homeostatic mechanism, allowing IMPDH to sense changes in the one-carbon folate pathway.
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Affiliation(s)
- S John Calise
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Daniel L Purich
- Department of Biochemistry and Molecular Biology, University of Florida, 1200 Newell Drive, Gainesville, FL 32610-0245, USA
| | - Thuy Nguyen
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Dania A Saleem
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Claire Krueger
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Joyce D Yin
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
| | - Edward K L Chan
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424, USA
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19
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Labesse G, Alexandre T, Gelin M, Haouz A, Munier-Lehmann H. Crystallographic studies of two variants ofPseudomonas aeruginosaIMPDH with impaired allosteric regulation. ACTA ACUST UNITED AC 2015; 71:1890-9. [DOI: 10.1107/s1399004715013115] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/07/2015] [Indexed: 11/10/2022]
Abstract
Inosine-5′-monophosphate dehydrogenases (IMPDHs), which are the rate-limiting enzymes in guanosine-nucleotide biosynthesis, are important therapeutic targets. Despite in-depth functional and structural characterizations of various IMPDHs, the role of the Bateman domain containing two CBS motifs remains controversial. Their involvement in the allosteric regulation ofPseudomonas aeruginosaIMPDH by Mg-ATP has recently been reported. To better understand the function of IMPDH and the importance of the CBS motifs, the structure of a variant devoid of these modules (ΔCBS) was solved at high resolution in the apo form and in complex with IMP. In addition, a single amino-acid substitution variant, D199N, was also structurally characterized: the mutation corresponds to the autosomal dominant mutant D226N of human IMPDH1, which is responsible for the onset of the retinopathy adRP10. These new structures shed light onto the possible mechanism of regulation of the IMPDH enzymatic activity. In particular, three conserved loops seem to be key players in this regulation as they connect the tetramer–tetramer interface with the active site and show significant modification upon substrate binding.
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20
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Buey RM, Ledesma-Amaro R, Balsera M, de Pereda JM, Revuelta JL. Increased riboflavin production by manipulation of inosine 5'-monophosphate dehydrogenase in Ashbya gossypii. Appl Microbiol Biotechnol 2015; 99:9577-89. [PMID: 26150243 DOI: 10.1007/s00253-015-6710-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/15/2015] [Accepted: 05/19/2015] [Indexed: 12/13/2022]
Abstract
Guanine nucleotides are the precursors of essential biomolecules including nucleic acids and vitamins such as riboflavin. The enzyme inosine-5'-monophosphate dehydrogenase (IMPDH) catalyzes the ratelimiting step in the guanine nucleotide de novo biosynthetic pathway and plays a key role in controlling the cellular nucleotide pools. Thus, IMPDH is an important metabolic bottleneck in the guanine nucleotide synthesis, susceptible of manipulation by means of metabolic engineering approaches. Herein, we report the functional and structural characterization of the IMPDH enzyme from the industrial fungus Ashbya gossypii. Our data show that the overexpression of the IMPDH gene increases the metabolic flux through the guanine pathway and ultimately enhances 40 % riboflavin production with respect to the wild type. Also, IMPDH disruption results in a 100-fold increase of inosine excretion to the culture media. Our results contribute to the developing metabolic engineering toolbox aiming at improving the production of metabolites with biotechnological interest in A. gossypii.
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Affiliation(s)
- Rubén M Buey
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007, Salamanca, Spain.
| | | | - Mónica Balsera
- Department Abiotic Stress, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, C/ Cordel de Merinas 40-52, 37008, Salamanca, Spain
| | - José María de Pereda
- Instituto de Biología Celular y Molecular del Cáncer, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Campus Miguel de Unamuno, 37007, Salamanca, Spain
| | - José Luis Revuelta
- Metabolic Engineering Group, Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, Campus Miguel de Unamuno, 37007, Salamanca, Spain.
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21
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Cho JH, Coats SJ, Schinazi RF. Synthesis of carbocyclic nucleoside analogs with five-membered heterocyclic nucleobases. Tetrahedron Lett 2015; 56:3587-3590. [PMID: 26028788 PMCID: PMC4446795 DOI: 10.1016/j.tetlet.2015.01.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
New carbocyclic nucleoside analogs with five-membered heterocyclic nucleobases were synthesized and evaluated as potential anti-HIV and anti-HCV agents. Among the synthesized carbocyclic nucleoside analogs, the pyrazole amide 15f exhibited modest selective anti-HIV-1 activity (EC50 = 24 µM).
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Affiliation(s)
- Jong hyun Cho
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, and Veterans Affairs Medical Center, Atlanta, GA 30322, USA
| | | | - Raymond F. Schinazi
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, and Veterans Affairs Medical Center, Atlanta, GA 30322, USA
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22
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Bioactive nucleoside analogues possessing selected five-membered azaheterocyclic bases. Eur J Med Chem 2015; 97:409-18. [DOI: 10.1016/j.ejmech.2014.11.057] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/25/2014] [Accepted: 11/27/2014] [Indexed: 11/23/2022]
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23
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Mazzucco MB, Talarico LB, Vatansever S, Carro AC, Fascio ML, D'Accorso NB, García CC, Damonte EB. Antiviral activity of an N-allyl acridone against dengue virus. J Biomed Sci 2015; 22:29. [PMID: 25908170 PMCID: PMC4407772 DOI: 10.1186/s12929-015-0134-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 04/08/2015] [Indexed: 12/19/2022] Open
Abstract
Background Dengue virus (DENV), a member of the family Flaviviridae, is at present the most widespread causative agent of a human viral disease transmitted by mosquitoes. Despite the increasing incidence of this pathogen, there are no antiviral drugs or vaccines currently available for treatment or prevention. In a previous screening assay, we identified a group of N-allyl acridones as effective virus inhibitors. Here, the antiviral activity and mode of action targeted to viral RNA replication of one of the most active DENV-2 inhibitors was further characterized. Results The compound 10-allyl-7-chloro-9(10H)-acridone, designated 3b, was active to inhibit the in vitro infection of Vero cells with the four DENV serotypes, with effective concentration 50% (EC50) values in the range 12.5-27.1 μM, as determined by virus yield inhibition assays. The compound was also effective in human HeLa cells. No cytotoxicity was detected at 3b concentrations up to 1000 μM. Mechanistic studies demonstrated that virus entry into the host cell was not affected, whereas viral RNA synthesis was strongly inhibited, as quantified by real time RT-PCR. The addition of exogenous guanosine together with 3b rescued only partially the infectivity of DENV-2. Conclusions The acridone derivative 3b selectively inhibits the infection of Vero cells with the four DENV serotypes without a direct interaction with the host cell or the virion but interfering specifically with the intracellular virus multiplication. The mode of antiviral action for this acridone apparently involves the cellular enzyme inosine-monophospahe dehydrogenase together with another still unidentified target related to DENV RNA synthesis.
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Affiliation(s)
- María B Mazzucco
- Laboratorio de Virología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Piso 4, Buenos Aires, Pabellón, 1428, Argentina. .,Present address: Laboratorio de Reproducción y Metabolismo, Facultad de Medicina, CEFYBO-CONICET, UBA, Buenos Aires, 1121, Argentina.
| | - Laura B Talarico
- Laboratorio de Virología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Piso 4, Buenos Aires, Pabellón, 1428, Argentina. .,Present address: Fundación Infant, Buenos Aires, 1406, Argentina.
| | - Sezen Vatansever
- Graduate School of Science and Engineering, Koc University, Rumelifener yolu, Istanbul, Sarıyer, 34450, Turke.
| | - Ana C Carro
- Laboratorio de Virología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Piso 4, Buenos Aires, Pabellón, 1428, Argentina. .,IQUIBICEN-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - Mirta L Fascio
- CIHIDECAR (CONICET), Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Pabellón 2, Piso 3, Buenos Aires, 1428, Argentina.
| | - Norma B D'Accorso
- CIHIDECAR (CONICET), Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Pabellón 2, Piso 3, Buenos Aires, 1428, Argentina.
| | - Cybele C García
- Laboratorio de Virología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Piso 4, Buenos Aires, Pabellón, 1428, Argentina. .,IQUIBICEN-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - Elsa B Damonte
- Laboratorio de Virología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Piso 4, Buenos Aires, Pabellón, 1428, Argentina. .,IQUIBICEN-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
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24
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Alexandre T, Rayna B, Munier-Lehmann H. Two classes of bacterial IMPDHs according to their quaternary structures and catalytic properties. PLoS One 2015; 10:e0116578. [PMID: 25706619 PMCID: PMC4338043 DOI: 10.1371/journal.pone.0116578] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/10/2014] [Indexed: 11/19/2022] Open
Abstract
Inosine-5'-monophosphate dehydrogenase (IMPDH) occupies a key position in purine nucleotide metabolism. In this study, we have performed the biochemical and physico-chemical characterization of eight bacterial IMPDHs, among which six were totally unexplored. This study led to a classification of bacterial IMPDHs according to the regulation of their catalytic properties and their quaternary structures. Class I IMPDHs are cooperative enzymes for IMP, which are activated by MgATP and are octameric in all tested conditions. On the other hand, class II IMPDHs behave as Michaelis-Menten enzymes for both substrates and are tetramers in their apo state or in the presence of IMP, which are shifted to octamers in the presence of NAD or MgATP. Our work provides new insights into the IMPDH functional regulation and a model for the quaternary structure modulation is proposed.
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Affiliation(s)
- Thomas Alexandre
- Institut Pasteur, Unité de Chimie et Biocatalyse, Département de Biologie Structurale et Chimie, 28 rue du Dr Roux, F-75015, Paris, France
- Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 3523, F-75015, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, F-75205, Paris, France
| | - Bertrand Rayna
- Institut Pasteur, Proteopole, Plateforme de biophysique des macromolecules et de leurs interactions, 25 rue du Dr Roux, F-75015, Paris, France
- Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 3528, F-75015, Paris, France
| | - Hélène Munier-Lehmann
- Institut Pasteur, Unité de Chimie et Biocatalyse, Département de Biologie Structurale et Chimie, 28 rue du Dr Roux, F-75015, Paris, France
- Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 3523, F-75015, Paris, France
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25
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Jefferies R, Yang R, Woh CK, Weldt T, Milech N, Estcourt A, Armstrong T, Hopkins R, Watt P, Reid S, Armson A, Ryan UM. Target validation of the inosine monophosphate dehydrogenase (IMPDH) gene in Cryptosporidium using Phylomer(®) peptides. Exp Parasitol 2014; 148:40-8. [PMID: 25447124 DOI: 10.1016/j.exppara.2014.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 11/07/2014] [Indexed: 01/03/2023]
Abstract
Cryptosporidiosis, a gastroenteric disease characterised mainly by diarrheal illnesses in humans and mammals is caused by infection with the protozoan parasite Cryptosporidium. Treatment options for cryptosporidiosis are limited, with the current therapeutic nitazoxanide, only partly efficacious in immunocompetent individuals. The parasite lacks de novo purine synthesis, and is exclusively dependant on purine salvage from its host. Inhibition of the inosine 5' monophosphate dehydrogenase (IMPDH), a purine salvage enzyme that is essential for DNA synthesis, thereby offers a potential drug target against this parasite. In the present study, a yeast-two-hybrid system was used to identify Phylomer peptides within a library constructed from the genomes of 25 phylogenetically diverse bacteria that targeted the IMPDH of Cryptosporidium parvum (IMPcp) and Cryptosporidium hominis (IMPch). We identified 38 unique interacting Phylomers, of which, 12 were synthesised and screened against C. parvum in vitro. Two Phylomers exhibited significant growth inhibition (81.2-83.8% inhibition; P < 0.05), one of which consistently exhibited positive interactions with IMPcp and IMPch during primary and recapitulation yeast two-hybrid screening and did not interact with either of the human IMPDH proteins. The present study highlightsthe potential of Phylomer peptides as target validation tools for Cryptosporidium and other organisms and diseases because of their ability to bind with high affinity to target proteins and disrupt function.
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Affiliation(s)
- R Jefferies
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia; Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - R Yang
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - C K Woh
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia; Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - T Weldt
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - N Milech
- Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - A Estcourt
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - T Armstrong
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - R Hopkins
- Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - P Watt
- Phylogica, Telethon Institute for Child Health Research, Subiaco, Western Australia, Australia
| | - S Reid
- School of Population Health, The University of Queensland, Herston, Queensland, Australia
| | - A Armson
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - U M Ryan
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia.
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Cholewiński G, Iwaszkiewicz-Grześ D, Prejs M, Głowacka A, Dzierzbicka K. Synthesis of the inosine 5′-monophosphate dehydrogenase (IMPDH) inhibitors. J Enzyme Inhib Med Chem 2014; 30:550-63. [DOI: 10.3109/14756366.2014.951349] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Calise SJ, Carcamo WC, Krueger C, Yin JD, Purich DL, Chan EKL. Glutamine deprivation initiates reversible assembly of mammalian rods and rings. Cell Mol Life Sci 2014; 71:2963-73. [PMID: 24477477 PMCID: PMC11113311 DOI: 10.1007/s00018-014-1567-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 12/21/2013] [Accepted: 01/16/2014] [Indexed: 02/06/2023]
Abstract
Rods and rings (RR) are protein assemblies composed of cytidine triphosphate synthetase type 1 (CTPS1) and inosine monophosphate dehydrogenase type 2 (IMPDH2), key enzymes in CTP and GTP biosynthesis. Small-molecule inhibitors of CTPS1 or IMPDH2 induce RR assembly in various cancer cell lines within 15 min to hours. Since glutamine is an essential amide nitrogen donor in these nucleotide biosynthetic pathways, glutamine deprivation was examined to determine whether it leads to RR formation. HeLa cells cultured in normal conditions did not show RR, but after culturing in media lacking glutamine, short rods (<2 μm) assembled after 24 h, and longer rods (>5 μm) formed after 48 h. Upon supplementation with glutamine or guanosine, these RR underwent almost complete disassembly within 15 min. Inhibition of glutamine synthetase with methionine sulfoximine also increased RR assembly in cells deprived of glutamine. Taken together, our data support the hypothesis that CTP/GTP biosynthetic enzymes polymerize to form RR in response to a decreased intracellular level of glutamine. We speculate that rod and ring formation is an adaptive metabolic response linked to disruption of glutamine homeostasis.
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Affiliation(s)
- S. John Calise
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424 USA
| | - Wendy C. Carcamo
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424 USA
| | - Claire Krueger
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424 USA
| | - Joyce D. Yin
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424 USA
| | - Daniel L. Purich
- Department of Biochemistry and Molecular Biology, University of Florida, 1600 SW Archer Rd., Gainesville, FL 32610-0245 USA
| | - Edward K. L. Chan
- Department of Oral Biology, University of Florida, 1395 Center Drive, Gainesville, FL 32610-0424 USA
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28
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Juda P, Smigová J, Kováčik L, Bártová E, Raška I. Ultrastructure of cytoplasmic and nuclear inosine-5'-monophosphate dehydrogenase 2 "rods and rings" inclusions. J Histochem Cytochem 2014; 62:739-50. [PMID: 24980853 DOI: 10.1369/0022155414543853] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Inosine-5'-monophosphate dehydrogenase catalyzes the critical step in the de novo synthesis of guanosine nucleotides: the oxidation of inosine monophosphate to xanthosine monophosphate. This reaction can be inhibited by specific inhibitors, such as ribavirin or mycophenolic acid, which are widely used in clinical treatment when required to inhibit the proliferation of viruses or cells. However, it was recently found that such an inhibition affects the cells, leading to a redistribution of IMPDH2 and the appearance of IMPDH2 inclusions in the cytoplasm. According to their shape, these inclusions have been termed "Rods and Rings" (R&R). In this work, we focused on the subcellular localization of IMPDH2 protein and the ultrastructure of R&R inclusions. Using microscopy and western blot analysis, we show the presence of nuclear IMPDH2 in human cells. We also show that the nuclear pool has an ability to form Rod structures after inhibition by ribavirin. Concerning the ultrastructure, we observed that R&R inclusions in cellulo correspond to the accumulation of fibrous material that is not surrounded by a biological membrane. The individual fibers are composed of regularly repeating subunits with a length of approximately 11 nm. Together, our findings describe the localization of IMPDH2 inside the nucleus of human cells as well as the ultrastructure of R&R inclusions.
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Affiliation(s)
- Pavel Juda
- Charles University in Prague, First Faculty of Medicine, Institute of Cellular Biology and Pathology, Czech Republic (PJ, JS, LK, IR)Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Brno, Czech Republic (EB)
| | - Jana Smigová
- Charles University in Prague, First Faculty of Medicine, Institute of Cellular Biology and Pathology, Czech Republic (PJ, JS, LK, IR)Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Brno, Czech Republic (EB)
| | - Lubomír Kováčik
- Charles University in Prague, First Faculty of Medicine, Institute of Cellular Biology and Pathology, Czech Republic (PJ, JS, LK, IR)Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Brno, Czech Republic (EB)
| | - Eva Bártová
- Charles University in Prague, First Faculty of Medicine, Institute of Cellular Biology and Pathology, Czech Republic (PJ, JS, LK, IR)Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Brno, Czech Republic (EB)
| | - Ivan Raška
- Charles University in Prague, First Faculty of Medicine, Institute of Cellular Biology and Pathology, Czech Republic (PJ, JS, LK, IR)Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Brno, Czech Republic (EB)
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Rostirolla DC, Milech de Assunção T, Bizarro CV, Basso LA, Santos DS. Biochemical characterization of Mycobacterium tuberculosis IMP dehydrogenase: kinetic mechanism, metal activation and evidence of a cooperative system. RSC Adv 2014. [DOI: 10.1039/c4ra02142h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Proposed kinetic mechanism forMtIMPDH in the presence of K+.
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Affiliation(s)
- Diana Carolina Rostirolla
- Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF)
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB)
- Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS)
- Porto Alegre, Brazil
- Programa de Pós-Graduação em Medicina e Ciências da Saúde
| | | | - Cristiano Valim Bizarro
- Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF)
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB)
- Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS)
- Porto Alegre, Brazil
| | - Luiz Augusto Basso
- Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF)
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB)
- Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS)
- Porto Alegre, Brazil
- Programa de Pós-Graduação em Medicina e Ciências da Saúde
| | - Diogenes Santiago Santos
- Centro de Pesquisas em Biologia Molecular e Funcional (CPBMF)
- Instituto Nacional de Ciência e Tecnologia em Tuberculose (INCT-TB)
- Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS)
- Porto Alegre, Brazil
- Programa de Pós-Graduação em Medicina e Ciências da Saúde
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Zhong ZJ, Zhang DJ, Peng ZG, Li YH, Shan GZ, Zuo LM, Wu LT, Li SY, Gao RM, Li ZR. Synthesis and antiviral activity of a novel class of (5-oxazolyl)phenyl amines. Eur J Med Chem 2013; 69:32-43. [DOI: 10.1016/j.ejmech.2013.07.053] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 07/27/2013] [Accepted: 07/30/2013] [Indexed: 10/26/2022]
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31
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Bairagya HR, Mukhopadhyay BP, Sekar K. Conserved water mediated H-bonding dynamics of inhibitor, cofactor, Asp 364 and Asn 303 in human IMPDH II. J Biomol Struct Dyn 2013; 26:497-507. [PMID: 19108589 DOI: 10.1080/07391102.2009.10507265] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The IMPDH (Inosine monophosphate dehydrogenase)-II is largely produced in cancer cells. Extensive MD-simulation (2 ns) of the 1B3O, 1NFB, 1NF7, 1LRT, and 1MEW PDB-structures revealed the presence of a conserved water molecule, which is H-bonded and stabilized by the surrounding ribose hydroxyl (O2) of inhibitor, nitrogen (NN) of cofactor, carboxyl oxygen (OD2) and amide nitrogen atoms of the active site Asp 364 and Asn 303 of human. These water-mediated interaction are partially supported in the solvated and X-ray structures. The stereochemistry of the four- centered H-bonds around the conserved water center may be exploited to design a better model inhibitor for IMPDH-II.
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Affiliation(s)
- Hridoy R Bairagya
- Department of Chemistry, National Institute of Technology-Durgapur, West Bengal, Durgapur-713209, India
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32
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MgATP regulates allostery and fiber formation in IMPDHs. Structure 2013; 21:975-85. [PMID: 23643948 DOI: 10.1016/j.str.2013.03.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/11/2013] [Accepted: 03/14/2013] [Indexed: 11/22/2022]
Abstract
Inosine-5'-monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme in nucleotide biosynthesis studied as an important therapeutic target and its complex functioning in vivo is still puzzling and debated. Here, we highlight the structural basis for the regulation of IMPDHs by MgATP. Our results demonstrate the essential role of the CBS tandem, conserved among almost all IMPDHs. We found that Pseudomonas aeruginosa IMPDH is an octameric enzyme allosterically regulated by MgATP and showed that this octameric organization is widely conserved in the crystal structures of other IMPDHs. We also demonstrated that human IMPDH1 adopts two types of complementary octamers that can pile up into isolated fibers in the presence of MgATP. The aggregation of such fibers in the autosomal dominant mutant, D226N, could explain the onset of the retinopathy adRP10. Thus, the regulatory CBS modules in IMPDHs are functional and they can either modulate catalysis or macromolecular assembly.
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Popsavin M, Spaić S, Svirčev M, Kojić V, Bogdanović G, Popsavin V. Synthesis and in vitro antitumour screening of 2-(β-d-xylofuranosyl)thiazole-4-carboxamide and two novel tiazofurin analogues with substituted tetrahydrofurodioxol moiety as a sugar mimic. Bioorg Med Chem Lett 2012; 22:6700-4. [DOI: 10.1016/j.bmcl.2012.08.093] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 08/23/2012] [Accepted: 08/25/2012] [Indexed: 11/27/2022]
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34
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Bairagya HR, Mukhopadhyay BP, Bera AK. Role of salt bridge dynamics in inter domain recognition of human IMPDH isoforms: an insight to inhibitor topology for isoform-II. J Biomol Struct Dyn 2012; 29:441-62. [PMID: 22066532 DOI: 10.1080/07391102.2011.10507397] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Inosine monophosphate dehydrogenase (IMPDH) enzyme involves in the biosynthesis pathway of guanosine nucleotide. Type II isoform of the enzyme is selectively upregulated in neoplastic fast replicating lymphocytes and CML cancer cells. The hIMPDH-II is an excellent target for antileukemic agent. The detailed investigation during MD-Simulation (15 ns) of three different unliganded structures (1B3O, 1JCN and 1JR1) have clearly explored the salt bridge mediated stabilization of inter or intra domain (catalytic domains I(N), I(C) with res. Id. 28-111 and 233-504, whereas two CBS domains C₁, C₂ are 112-171 and 172-232) in IMPDH enzyme which are mostly inaccessible in their X-rays structures. The salt bridge interaction in I(N)---C₁ inter-domain of hIMPDH-I, I(N)---C₂ of IMPDH-II and C₁---I(C) of nhIMPDH-II are discriminative features among the isoforms. The I(N)---C₂ recognition in hIMPDH-II (1B3O) is missing in type-I isoform (1JCN). The salt bridge interaction D232---K238 at the surface of protein and the involvement of three conserved water molecules or the hydrophilic centers (WA²³²(OD1), WB ²³²(OD2) and W²³⁸(NZ)) to those acidic and basic residues seem to be unique in hIMPDH-II. The hydrophilic susceptibility, geometrical and electronic consequences of this salt bridge interaction could be useful to design the topology of specific inhibitor for hIMPDH-II which may not be effective for hIMPDH-I. Possibly, the aliphatic ligand containing carboxyl, amide or hydrophilic groups with flexible structure may be implicated for hIMPDH-II inhibitor design using the conserved water mimic drug design protocol.
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Affiliation(s)
- Hridoy R Bairagya
- Department of Chemistry, National Institute of Technology-Durgapur, West Bengal, Durgapur-713209, India
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35
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Makowska-Grzyska M, Kim Y, Wu R, Wilton R, Gollapalli DR, Wang XK, Zhang R, Jedrzejczak R, Mack JC, Maltseva N, Mulligan R, Binkowski TA, Gornicki P, Kuhn ML, Anderson WF, Hedstrom L, Joachimiak A. Bacillus anthracis inosine 5'-monophosphate dehydrogenase in action: the first bacterial series of structures of phosphate ion-, substrate-, and product-bound complexes. Biochemistry 2012; 51:6148-63. [PMID: 22788966 DOI: 10.1021/bi300511w] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Inosine 5'-monophosphate dehydrogenase (IMPDH) catalyzes the first unique step of the GMP branch of the purine nucleotide biosynthetic pathway. This enzyme is found in organisms of all three kingdoms. IMPDH inhibitors have broad clinical applications in cancer treatment, as antiviral drugs and as immunosuppressants, and have also displayed antibiotic activity. We have determined three crystal structures of Bacillus anthracis IMPDH, in a phosphate ion-bound (termed "apo") form and in complex with its substrate, inosine 5'-monophosphate (IMP), and product, xanthosine 5'-monophosphate (XMP). This is the first example of a bacterial IMPDH in more than one state from the same organism. Furthermore, for the first time for a prokaryotic enzyme, the entire active site flap, containing the conserved Arg-Tyr dyad, is clearly visible in the structure of the apoenzyme. Kinetic parameters for the enzymatic reaction were also determined, and the inhibitory effect of XMP and mycophenolic acid (MPA) has been studied. In addition, the inhibitory potential of two known Cryptosporidium parvum IMPDH inhibitors was examined for the B. anthracis enzyme and compared with those of three bacterial IMPDHs from Campylobacter jejuni, Clostridium perfringens, and Vibrio cholerae. The structures contribute to the characterization of the active site and design of inhibitors that specifically target B. anthracis and other microbial IMPDH enzymes.
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Affiliation(s)
- Magdalena Makowska-Grzyska
- Center for Structural Genomics of Infectious Diseases, University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637, USA
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36
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Mironiuk-Puchalska E, Koszytkowska-Stawińska M, Sas W, De Clercq E, Naesens L. Synthesis of novel aza-analogues of tiazofurin with 2-[5,5-bis(hydroxymethyl)pyrrolidin-2-yl] framework as sugar mimic. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2012; 31:72-84. [PMID: 22257212 DOI: 10.1080/15257770.2011.643848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
The novel aza-analogues of tiazofurin (TZF) with 2-[5,5-bis(hydroxymethyl)pyrrolidin-2-yl] moiety, as sugar mimic, were synthesized from O,O-cyclohexylidene derivative of 4,4-bis(hydroxymethyl)-4-nitrobutanal in multi-gram scale. The synthetic route consisted of three stages: (i) the synthesis of corresponding derivative of 5,5-bis(hydroxymethyl)pyrrolidine-2-carbonitrile, (ii) the construction of ethyl thiazole-2-carboxylate part by the conversion of the pyrrolidine-2-carbonitrile into the N-trifluoroacetyl derivative followed by cyclocondensation with L-cysteine ethyl ester and then by dehydrogenation, and (iii) the final transformation of the ethyl thiazole-4-carboxylate into the aza-analogues of TZF. The TZF aza-analogues were evaluated for their antiviral activities in cell-culture-based assays.
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37
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Hedstrom L. The dynamic determinants of reaction specificity in the IMPDH/GMPR family of (β/α)(8) barrel enzymes. Crit Rev Biochem Mol Biol 2012; 47:250-63. [PMID: 22332716 DOI: 10.3109/10409238.2012.656843] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The inosine monophosphate dehydrogenase (IMPDH)/guanosine monophosphate reductase (GMPR) family of (β/α)(8) enzymes presents an excellent opportunity to investigate how subtle changes in enzyme structure change reaction specificity. IMPDH and GMPR bind the same ligands with similar affinities and share a common set of catalytic residues. Both enzymes catalyze a hydride transfer reaction involving a nicotinamide cofactor hydride, and both reactions proceed via the same covalent intermediate. In the case of IMPDH, this intermediate reacts with water, while in GMPR it reacts with ammonia. In both cases, the two chemical transformations are separated by a conformational change. In IMPDH, the conformational change involves a mobile protein flap while in GMPR, the cofactor moves. Thus reaction specificity is controlled by differences in dynamics, which in turn are controlled by residues outside the active site. These findings have some intriguing implications for the evolution of the IMPDH/GMPR family.
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Affiliation(s)
- Lizbeth Hedstrom
- Departments of Biology and Chemistry, Brandeis University, Waltham, MA 02454, USA.
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Popsavin M, Svirčev M, Torović L, Bogdanović G, Kojić V, Jakimov D, Spaić S, Aleksić L, Popsavin V. Antitumour tiazofurin analogues embedded with an amide moiety at the C-2′ position. Tetrahedron 2011. [DOI: 10.1016/j.tet.2011.06.090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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39
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Inosine monophosphate dehydrogenase as a target for antiviral, anticancer, antimicrobial and immunosuppressive therapeutics. Future Med Chem 2011; 2:81-92. [PMID: 21426047 DOI: 10.4155/fmc.09.147] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Inosine monophosphate dehydrogenase (IMPDH) catalyzes the rate-limiting step in the de novo biosynthesis of guanine nucleotides. In recent years it has become the target of multiple drugs in an attempt to cure a variety of diseases. Possible therapeutic drugs range from antiviral and anticancer to immunosuppressive targets. Research has shown that if IMPDH is effectively inhibited, cancerous growth can be slowed and virus replication can be stopped. Microbial and parasitic IMPDH differ significantly from the human isoforms and targeting those isoforms could lead to effective treatments for many diseases. Inhibiting IMPDH is an extremely promising therapy for a variety of disease states. Isoform- and species-selective inhibition is desirable and scientists are making significant progress in these areas.
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Yang N, Wang J, Li J, Wang QH, Wang Y, Cheng MS. A three-dimensional pharmacophore model for IMPDH inhibitors. Chem Biol Drug Des 2011; 78:175-82. [PMID: 21507206 DOI: 10.1111/j.1747-0285.2011.01128.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Inosine 5'-monophosphate dehydrogenase (IMPDH) is a key enzyme in the de novo synthesis of guanosine nucleotides. It is considered an important target in the quest for drugs in the immunosuppressive, antiviral, antibacterial and anticancer therapeutic areas. In this study, a chemical feature-based pharmacophore model of IMPDH inhibitors has been firstly developed with the aid of the HypoRefine protocol within Discovery Studio 2.5. The best model for IMPDH inhibitors, Hypo1-1, was characterized by the best correlation coefficient (0.97595) and the lowest RMSD (0.582058). It consisted of one hydrogen-bond donor, one hydrogen-bond acceptor, one aromatic ring and one hydrophobic feature, as well as two excluded volumes. The model was validated using a wide range of test molecules and a cross-validation. Furthermore, the pharmacophore features were confirmed by molecular docking studies. The pharmacophore model could quantitatively predict inhibitor activity and identify highly potent molecules. Therefore, the present results could be valuable for the discovery and development of specific IMPDH inhibitors.
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Affiliation(s)
- Na Yang
- Key Laboratory of Structure-Based Drugs Design and Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
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41
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Ostrowski T, Januszczyk P, Cieslak M, Kazmierczak-Baranska J, Nawrot B, Bartoszak-Adamska E, Zeidler J. 5-Ethynyl-1-β-D-ribofuranosyl-1H-[1,2,3]triazole-4-carboxylic acid amide (ETCAR) and its analogues: synthesis and cytotoxic properties. Bioorg Med Chem 2011; 19:4386-98. [PMID: 21684167 DOI: 10.1016/j.bmc.2011.05.050] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/05/2011] [Accepted: 05/09/2011] [Indexed: 11/16/2022]
Abstract
Efficient Pd(0)-catalysed synthesis of 5-alkynyl-1-β-D-ribofuranosyl-1H-[1,2,3]triazole-4-carboxylic acid amide depends on the presence of different protecting groups of the ribose moiety. Peracetylated 5-iodo substrate (15) couples with terminal alkynes or trimethyl-[(tributylstannyl)ethynyl]silane in 50-71% and 72% yield (ETCAR), respectively, although its hydrodehalogenation to 19 is noticeable. On the other hand, hydrodehalogenation of acetonide (16) predominates over coupling with terminal alkyne and slightly decreases a yield of cross-coupling reaction with trimethyl[(tributylstannyl)ethynyl]silane. Alternative conditions of reaction with terminal alkynes, to exclude so far identified hydride sources to produce hydridopalladium species, have been established for acetonide 16 and allowed to achieve 72% of coupling. Fluoromethyl derivative (42) was prepared from its 5-hydroxymethyl precursor by fluorination with DAST. Additionally, X-ray structural analysis of 42 was performed. All 1,2,3-triazolonucleosides and two synthesized cycloSal-pronucleotides were evaluated for cytotoxic activity against K562, HeLa and HUVEC cells.
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Affiliation(s)
- Tomasz Ostrowski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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42
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Sharling L, Liu X, Gollapalli DR, Maurya SK, Hedstrom L, Striepen B. A screening pipeline for antiparasitic agents targeting cryptosporidium inosine monophosphate dehydrogenase. PLoS Negl Trop Dis 2010; 4:e794. [PMID: 20706578 PMCID: PMC2919388 DOI: 10.1371/journal.pntd.0000794] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 07/14/2010] [Indexed: 11/30/2022] Open
Abstract
Background The protozoan parasite Cryptosporidium parvum is responsible for significant disease burden among children in developing countries. In addition Cryptosporidiosis can result in chronic and life-threatening enteritis in AIDS patients, and the currently available drugs lack efficacy in treating these severe conditions. The discovery and development of novel anti-cryptosporidial therapeutics has been hampered by the poor experimental tractability of this pathogen. While the genome sequencing effort has identified several intriguing new targets including a unique inosine monophosphate dehydrogenase (IMPDH), pursuing these targets and testing inhibitors has been frustratingly difficult. Methodology and Principal Findings Here we have developed a pipeline of tools to accelerate the in vivo screening of inhibitors of C. parvum IMPDH. We have genetically engineered the related parasite Toxoplasma gondii to serve as a model of C. parvum infection as the first screen. This assay provides crucial target validation and a large signal window that is currently not possible in assays involving C. parvum. To further develop compounds that pass this first filter, we established a fluorescence-based assay of host cell proliferation, and a C. parvum growth assay that utilizes automated high-content imaging analysis for enhanced throughput. Conclusions and Significance We have used these assays to evaluate C. parvum IMPDH inhibitors emerging from our ongoing medicinal chemistry effort and have identified a subset of 1,2,3-triazole ethers that exhibit excellent in vivo selectivity in the T. gondii model and improved anti-cryptosporidial activity. Persistent diarrhea is a leading cause of illness and death among impoverished children, and a growing share of this disease burden can be attributed to the parasite Cryptosporidium. There are no vaccines to prevent Cryptosporidium infection, and the treatment options are limited and unreliable. Critically, no effective treatment exists for children or adults suffering from AIDS. Cryptosporidium presents many technical obstacles for drug discovery; perhaps the most important roadblock is the difficulty of monitoring drug action. Here we have developed a set of methods to accelerate the drug discovery process for cryptosporidiosis. We exploit the opportunities for experimental manipulation in the related parasite Toxoplasma to genetically engineer a Cryptosporidium model. This new model parasite mirrors the metabolism of Cryptosporidium for a particularly promising drug target that supplies the building blocks for DNA and RNA. Drug effectiveness can be assayed through simple fluorescence measurements for many candidates. Using this assay as an initial filter, and adapting other assays to a high throughput format, we identify several novel chemical compounds that exhibit markedly improved anti-cryptosporidial activity and excellent selectivity.
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Affiliation(s)
- Lisa Sharling
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Xiaoping Liu
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Deviprasad R. Gollapalli
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts, United States of America
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
| | - Sushil K. Maurya
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts, United States of America
| | - Lizbeth Hedstrom
- Department of Biology, Brandeis University, Waltham, Massachusetts, United States of America
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, United States of America
| | - Boris Striepen
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Nair V, Zhang F, Ma X, Bonsu E. Base-functionalized carbocyclic nucleosides: design, synthesis, and mechanism of antiviral activity. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2010; 28:408-23. [PMID: 20183592 DOI: 10.1080/15257770903044465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
New carbocyclic ribonucleosides with unsaturated groups at the C-2 position of the nucleobase were designed as potential RNA antiviral compounds. The design was based on the expectation that the monophosphates of these compounds would be inhibitors of the enzyme, IMPDH. Appropriate methodologies were developed to achieve the target molecules. Results from the initial in vitro antiviral studies are mentioned. The IMPDH-associated mechanism of the antiviral activity of the most active compound is supported by enzyme inhibition studies.
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Affiliation(s)
- Vasu Nair
- Department of Pharmaceutical and Biomedical Sciences and the Center for Drug Discovery, University of Georgia, Athens, Georgia, USA.
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Abstract
About 20 proteins are known to modify their activity upon interaction with C60. Their structures are present in a database that includes more than 1200 protein structures selected as possible targets for drugs and to represent the entire Protein Data Bank. The set was examined with an algorithm that appraises quantitatively the interaction of C60 and the surface of each protein. The redundancy of the set allows to establish the predictive power of the approach that finds explicitly the most probable site where C60 docks on each protein. About 80% of the known fullerene binding proteins fall in the top 10% of scorers. The close match between the model and experiments vouches for the accuracy of the model and validates its predictions. The sites of docking are shown and discussed in view of the existing experimental data available for protein-C60 interaction. A closer exam of the 10 top scorers is discussed in detail. New proteins that can interact with C60 are identified and discussed for possible future applications as drug targets and fullerene derivatives bioconjugate materials.
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Affiliation(s)
- Matteo Calvaresi
- Dipartimento di Chimica "G. Ciamician", Universita' di Bologna, V. F. Selmi 2, 40126 Bologna, Italy.
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Bairagya HR, Mukhopadhyay BP, Bera AK. Conserved water mediated recognition and the dynamics of active site Cys 331 and Tyr 411 in hydrated structure of human IMPDH-II. J Mol Recognit 2010; 24:35-44. [DOI: 10.1002/jmr.1021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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46
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Maurya SK, Gollapalli DR, Kirubakaran S, Zhang M, Johnson CR, Benjamin NN, Hedstrom L, Cuny GD. Triazole inhibitors of Cryptosporidium parvum inosine 5'-monophosphate dehydrogenase. J Med Chem 2009; 52:4623-30. [PMID: 19624136 DOI: 10.1021/jm900410u] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cryptosporidium parvum is an important human pathogen and potential bioterrorism agent. This protozoan parasite cannot salvage guanine or guanosine and therefore relies on inosine 5'-monophosphate dehydrogenase (IMPDH) for biosynthesis of guanine nucleotides and hence for survival. Because C. parvum IMPDH is highly divergent from the host counterpart, selective inhibitors could potentially be used to treat cryptosporidiosis with minimal effects on its mammalian host. A series of 1,2,3-triazole containing ether CpIMPDH inhibitors are described. A structure-activity relationship study revealed that a small alkyl group on the alpha-position of the ether was required, with the (R)-enantiomer significantly more active than the (S)-enantiomer. Electron-withdrawing groups in the 3- and/or 4-positions of the pendent phenyl ring were best, and conversion of the quinoline containing inhibitors to quinoline-N-oxides retained inhibitory activity both in the presence and absence of bovine serum albumin. The 1,2,3-triazole CpIMPDH inhibitors provide new tools for elucidating the role of IMPDH in C. parvum and may serve as potential therapeutics for treating cryptosporidiosis.
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Affiliation(s)
- Sushil K Maurya
- Department of Biology, Brandeis University, MS009, 415 South Street, Waltham, Massachusetts 02454, USA
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Popsavin M, Spaić S, Svirčev M, Kojić V, Bogdanović G, Pejanović V, Popsavin V. Synthesis of highly cytotoxic tiazofurin mimics bearing a 2,3-anhydro function in the furanose ring. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.06.100] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Affiliation(s)
- Lizbeth Hedstrom
- Department of Biology, Brandeis University, MS009, 415 South Street, Waltham, Massachusetts 02454, USA.
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49
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Nair V, Chi G, Shu Q, Julander J, Smee DF. A heterocyclic molecule with significant activity against dengue virus. Bioorg Med Chem Lett 2009; 19:1425-7. [PMID: 19185487 PMCID: PMC2692961 DOI: 10.1016/j.bmcl.2009.01.031] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 01/06/2009] [Accepted: 01/12/2009] [Indexed: 11/25/2022]
Abstract
There are no specific approved drugs or vaccines for the treatment or prevention of infectious dengue virus and there are very few compounds known that inhibit the replication of this virus. This letter describes the concise synthesis of two uracil-based multifunctional compounds. One of these compounds (1) has strong activity against dengue virus. It also exhibits low activity against a few other RNA viruses, but is highly active against yellow fever virus, a related flavivirus. It is likely that the mechanism of action of the antiviral activity of this compound is through its inhibition of the enzyme, inosine monophosphate dehydrogenase (IMPDH). Molecular modeling studies reveal that the compound can have specific hydrogen bonding interactions with a number of amino acids in the active site of IMPDH, a stacking interaction with the bound natural substrate, IMP, and the ability to interfere with the binding of NAD(+) with IMPDH, prior to the hydration step.
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Affiliation(s)
- Vasu Nair
- Department of Pharmaceutical and Biomedical Sciences and the Center for Drug Discovery, University of Georgia, Athens, GA 30602, USA
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Riera TV, Wang W, Josephine HR, Hedstrom L. A kinetic alignment of orthologous inosine-5'-monophosphate dehydrogenases. Biochemistry 2008; 47:8689-96. [PMID: 18642884 PMCID: PMC2646883 DOI: 10.1021/bi800674a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
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IMP dehydrogenase (IMPDH) catalyzes two very different chemical transformations, a dehydrogenase reaction and a hydrolysis reaction. The enzyme toggles between the open conformation required for the dehydrogenase reaction and the closed conformation of the hydrolase reaction by moving a mobile flap into the NAD site. Despite these multiple functional constraints, the residues of the flap and NAD site are highly diverged, and the equilibrium between open and closed conformations (Kc) varies widely. In order to understand how differences in the dynamic properties of the flap influence the catalytic cycle, we have delineated the kinetic mechanism of IMPDH from the pathogenic protozoan parasite Cryptosporidium parvum (CpIMPDH), which was obtained from a bacterial source through horizontal gene transfer, and its host counterpart, human IMPDH type 2 (hIMPDH2). Interestingly, the intrinsic binding energy of NAD+ differentially distributes across the dinucleotide binding sites of these two enzymes as well as in the previously characterized IMPDH from Tritrichomonas foetus (TfIMPDH). Both the dehydrogenase and hydrolase reactions display significant differences in the host and parasite enzymes, in keeping with the phylogenetic and structural divergence of their active sites. Despite large differences in Kc, the catalytic power of both the dehydrogenase and hydrolase conformations are similar in CpIMPDH and TfIMPDH. This observation suggests that the closure of the flap simply sets the stage for catalysis rather than plays a more active role in the chemical transformation. This work provides the essential mechanistic framework for drug discovery.
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Affiliation(s)
- Thomas V Riera
- Departments of Biochemistry and Chemistry, Brandeis University, Waltham, Massachusetts 02454, USA
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