1
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Coco L, Toci EM, Chen PYT, Drennan CL, Freel Meyers CL. Potent Inhibition of E. coli DXP Synthase by a gem-Diaryl Bisubstrate Analog. ACS Infect Dis 2024; 10:1312-1326. [PMID: 38513073 PMCID: PMC11019550 DOI: 10.1021/acsinfecdis.3c00734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/27/2024] [Accepted: 03/01/2024] [Indexed: 03/23/2024]
Abstract
New antimicrobial strategies are needed to address pathogen resistance to currently used antibiotics. Bacterial central metabolism is a promising target space for the development of agents that selectively target bacterial pathogens. 1-Deoxy-d-xylulose 5-phosphate synthase (DXPS) converts pyruvate and d-glyceraldehyde 3-phosphate (d-GAP) to DXP, which is required for synthesis of essential vitamins and isoprenoids in bacterial pathogens. Thus, DXPS is a promising antimicrobial target. Toward this goal, our lab has demonstrated selective inhibition of Escherichia coli DXPS by alkyl acetylphosphonate (alkylAP)-based bisubstrate analogs that exploit the requirement for ternary complex formation in the DXPS mechanism. Here, we present the first DXPS structure with a bisubstrate analog bound in the active site. Insights gained from this cocrystal structure guided structure-activity relationship studies of the bisubstrate scaffold. A low nanomolar inhibitor (compound 8) bearing a gem-dibenzyl glycine moiety conjugated to the acetylphosphonate pyruvate mimic via a triazole-based linker emerged from this study. Compound 8 was found to exhibit slow, tight-binding inhibition, with contacts to E. coli DXPS residues R99 and R478 demonstrated to be important for this behavior. This work has discovered the most potent DXPS inhibitor to date and highlights a new role of R99 that can be exploited in future inhibitor designs toward the development of a novel class of antimicrobial agents.
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Affiliation(s)
- Lauren
B. Coco
- Department
of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Eucolona M. Toci
- Department
of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Percival Yang-Ting Chen
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
| | - Catherine L. Drennan
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
- Howard
Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Caren L. Freel Meyers
- Department
of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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2
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Zia MP, Jain M, Muthukumaran J, Singh AK. Exploration of potential hit compounds targeting 1-deoxy-d-xylulose 5-phosphate reductoisomerase (IspC) from Acinetobacter baumannii: an in silico investigation. 3 Biotech 2024; 14:72. [PMID: 38362590 PMCID: PMC10864239 DOI: 10.1007/s13205-024-03923-w] [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: 07/11/2023] [Accepted: 01/07/2024] [Indexed: 02/17/2024] Open
Abstract
The emergence of carbapenem-resistant Acinetobacter baumannii, a highly concerning bacterial species designated as a Priority 1: Critical pathogen by the WHO, has become a formidable global threat. In this study, we utilised computational methods to explore the potent molecules capable of inhibiting the IspC enzyme, which plays a crucial role in the methylerythritol 4-phosphate (MEP) biosynthetic pathway. Employing high-throughput virtual screening of small molecules from the Enamine library, we focused on the highly conserved substrate binding site of the DXR target protein, resulting in the identification of 1000 potential compounds. Among these compounds, we selected the top two candidates (Z2615855584 and Z2206320703) based on Lipinski's rule of Five and ADMET filters, along with FR900098, a known IspC inhibitor, and DXP, the substrate of IspC, for molecular dynamics (MD) simulations. The MD simulation trajectories revealed remarkable structural and thermodynamic stability, as well as strong binding affinity, for all the IspC-ligand complexes. Furthermore, binding free energy calculations based on MM/PBSA (Molecular Mechanics/Poisson-Boltzmann Surface Area) methodology demonstrated significant interactions between the selected ligand molecules and IspC. Taking into consideration all the aforementioned criteria, we suggest Z2206320703 as the potent lead candidate against IspC. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-024-03923-w.
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Affiliation(s)
- Mahrukh Parveez Zia
- Department of Biotechnology, School of Engineering and Technology, Sharda University, P.C. 201310, Greater Noida, Uttar Pradesh India
| | - Monika Jain
- Department of Biotechnology, School of Engineering and Technology, Sharda University, P.C. 201310, Greater Noida, Uttar Pradesh India
| | - Jayaraman Muthukumaran
- Department of Biotechnology, School of Engineering and Technology, Sharda University, P.C. 201310, Greater Noida, Uttar Pradesh India
| | - Amit Kumar Singh
- Department of Biotechnology, School of Engineering and Technology, Sharda University, P.C. 201310, Greater Noida, Uttar Pradesh India
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3
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Antibacterial Activity of Allicin-Inspired Disulfide Derivatives against Xanthomonas axonopodis pv. citri. Int J Mol Sci 2022; 23:ijms231911947. [PMID: 36233251 PMCID: PMC9569821 DOI: 10.3390/ijms231911947] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/01/2022] [Accepted: 10/05/2022] [Indexed: 11/17/2022] Open
Abstract
Xanthomonas axonopodis pv. citri (Xac) belongs to the Gram-negative species, causing citrus canker that seriously affects the fruit yield and quality of many rutaceae plants. Herein, we found that compound 2-(butyldisulfanyl) quinazolin-4(3H)-one exhibited remarkable anti-Xac activity in vitro with a half effective concentration (EC50) of 2.6 μg/mL, while the positive controls thiodiazole-copper with 57 μg/mL and bismerthiazol with 68 μg/mL and this compound showed great anti-citrus canker activity in vivo. This active compound also was confirmed to reduce biofilm formation, increase the level of reactive oxygen species, damage the morphological structure of the bacteria, and cause bacterial death. Proteomics and RT-qPCR analysis results indicated that this compound down-regulated the expression of enzymes in the MEP (2-methyl-D-erythritol 4-phosphate) pathway and might achieve destructive ability of Xac. Overall, this study indicates that such derivatives could be a promising scaffold to develop novel bactericides to control citrus canker.
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4
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Boyd NK, Teng C, Frei CR. Brief Overview of Approaches and Challenges in New Antibiotic Development: A Focus On Drug Repurposing. Front Cell Infect Microbiol 2021; 11:684515. [PMID: 34079770 PMCID: PMC8165386 DOI: 10.3389/fcimb.2021.684515] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 05/04/2021] [Indexed: 12/19/2022] Open
Abstract
Drug repurposing, or identifying new uses for existing drugs, has emerged as an alternative to traditional drug discovery processes involving de novo synthesis. Drugs that are currently approved or under development for non-antibiotic indications may possess antibiotic properties, and therefore may have repurposing potential, either alone or in combination with an antibiotic. They might also serve as "antibiotic adjuvants" to enhance the activity of certain antibiotics.
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Affiliation(s)
- Natalie K Boyd
- College of Pharmacy, The University of Texas at Austin, San Antonio, TX, United States.,Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Chengwen Teng
- Department of Clinical Pharmacy and Outcomes Sciences, College of Pharmacy, The University of South Carolina, Columbia, SC, United States
| | - Christopher R Frei
- College of Pharmacy, The University of Texas at Austin, San Antonio, TX, United States.,Long School of Medicine, University of Texas Health San Antonio, San Antonio, TX, United States.,Research Department, South Texas Veterans Health Care System, San Antonio, TX, United States.,Pharmacy Department, University Health System, San Antonio, TX, United States
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5
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Malico AA, Calzini MA, Gayen AK, Williams GJ. Synthetic biology, combinatorial biosynthesis, and chemo‑enzymatic synthesis of isoprenoids. J Ind Microbiol Biotechnol 2020; 47:675-702. [PMID: 32880770 PMCID: PMC7666032 DOI: 10.1007/s10295-020-02306-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 08/27/2020] [Indexed: 12/12/2022]
Abstract
Isoprenoids are a large class of natural products with myriad applications as bioactive and commercial compounds. Their diverse structures are derived from the biosynthetic assembly and tailoring of their scaffolds, ultimately constructed from two C5 hemiterpene building blocks. The modular logic of these platforms can be harnessed to improve titers of valuable isoprenoids in diverse hosts and to produce new-to-nature compounds. Often, this process is facilitated by the substrate or product promiscuity of the component enzymes, which can be leveraged to produce novel isoprenoids. To complement rational enhancements and even re-programming of isoprenoid biosynthesis, high-throughput approaches that rely on searching through large enzymatic libraries are being developed. This review summarizes recent advances and strategies related to isoprenoid synthetic biology, combinatorial biosynthesis, and chemo-enzymatic synthesis, focusing on the past 5 years. Emerging applications of cell-free biosynthesis and high-throughput tools are included that culminate in a discussion of the future outlook and perspective of isoprenoid biosynthetic engineering.
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Affiliation(s)
| | - Miles A Calzini
- Department of Chemistry, NC State University, Raleigh, NC, 27695, USA
| | - Anuran K Gayen
- Department of Chemistry, NC State University, Raleigh, NC, 27695, USA
| | - Gavin J Williams
- Department of Chemistry, NC State University, Raleigh, NC, 27695, USA.
- Comparative Medicine Institute, NC State University, Raleigh, NC, 27695, USA.
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6
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Peters CE, Lamsa A, Liu RB, Quach D, Sugie J, Brumage L, Pogliano J, Lopez-Garrido J, Pogliano K. Rapid Inhibition Profiling Identifies a Keystone Target in the Nucleotide Biosynthesis Pathway. ACS Chem Biol 2018; 13:3251-3258. [PMID: 30133247 DOI: 10.1021/acschembio.8b00273] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Understanding the mechanism of action (MOA) of new antimicrobial agents is a critical step in drug discovery but is notoriously difficult for compounds that appear to inhibit multiple cellular pathways. We recently described image-based approaches [bacterial cytological profiling and rapid inducible profiling (RIP)] for identifying the cellular pathways targeted by antibiotics. Here we have applied these methods to examine the effects of proteolytically degrading enzymes involved in pyrimidine nucleotide biosynthesis, a pathway that produces intermediates for transcription, DNA replication, and cell envelope synthesis. We show that rapid removal of enzymes directly involved in deoxyribonucleotide synthesis blocks DNA replication. However, degradation of cytidylate kinase (CMK), which catalyzes reactions involved in the synthesis of both ribonucleotides and deoxyribonucleotides, blocks both DNA replication and wall teichoic acid biosynthesis, producing cytological effects identical to those created by simultaneously inhibiting both processes with the antibiotics ciprofloxacin and tunicamycin. Our results suggest that RIP can be used to identify and characterize potential keystone enzymes like CMK whose inhibition dramatically affects multiple pathways, thereby revealing important metabolic connections. Identifying and understanding the role of keystone targets might also help to determine the MOAs of drugs that appear to inhibit multiple targets.
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Affiliation(s)
- Christine E. Peters
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Anne Lamsa
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Roland B. Liu
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Diana Quach
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Joseph Sugie
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Lauren Brumage
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Joe Pogliano
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Javier Lopez-Garrido
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Kit Pogliano
- Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093, United States
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7
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Sanders S, Bartee D, Harrison MJ, Phillips PD, Koppisch AT, Freel Meyers CL. Growth medium-dependent antimicrobial activity of early stage MEP pathway inhibitors. PLoS One 2018; 13:e0197638. [PMID: 29771999 PMCID: PMC5957436 DOI: 10.1371/journal.pone.0197638] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 05/04/2018] [Indexed: 01/01/2023] Open
Abstract
The in vivo microenvironment of bacterial pathogens is often characterized by nutrient limitation. Consequently, conventional rich in vitro culture conditions used widely to evaluate antibacterial agents are often poorly predictive of in vivo activity, especially for agents targeting metabolic pathways. In one such pathway, the methylerythritol phosphate (MEP) pathway, which is essential for production of isoprenoids in bacterial pathogens, relatively little is known about the influence of growth environment on antibacterial properties of inhibitors targeting enzymes in this pathway. The early steps of the MEP pathway are catalyzed by 1-deoxy-d-xylulose 5-phosphate (DXP) synthase and reductoisomerase (IspC). The in vitro antibacterial efficacy of the DXP synthase inhibitor butylacetylphosphonate (BAP) was recently reported to be strongly dependent upon growth medium, with high potency observed under nutrient limitation and exceedingly weak activity in nutrient-rich conditions. In contrast, the well-known IspC inhibitor fosmidomycin has potent antibacterial activity in nutrient-rich conditions, but to date, its efficacy had not been explored under more relevant nutrient-limited conditions. The goal of this work was to thoroughly characterize the effects of BAP and fosmidomycin on bacterial cells under varied growth conditions. In this work, we show that activities of both inhibitors, alone and in combination, are strongly dependent upon growth medium, with differences in cellular uptake contributing to variance in potency of both agents. Fosmidomycin is dissimilar to BAP in that it displays relatively weaker activity in nutrient-limited compared to nutrient-rich conditions. Interestingly, while it has been generally accepted that fosmidomycin activity depends upon expression of the GlpT transporter, our results indicate for the first time that fosmidomycin can enter cells by an alternative mechanism under nutrient limitation. Finally, we show that the potency and relationship of the BAP-fosmidomycin combination also depends upon the growth medium, revealing a striking loss of BAP-fosmidomycin synergy under nutrient limitation. This change in BAP-fosmidomycin relationship suggests a shift in the metabolic and/or regulatory networks surrounding DXP accompanying the change in growth medium, the understanding of which could significantly impact targeting strategies against this pathway. More generally, our findings emphasize the importance of considering physiologically relevant growth conditions for predicting the antibacterial potential MEP pathway inhibitors and for studies of their intracellular targets.
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Affiliation(s)
- Sara Sanders
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - David Bartee
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Mackenzie J. Harrison
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Paul D. Phillips
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Andrew T. Koppisch
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- * E-mail:
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8
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Abstract
One of the main fundamental mechanisms of antibiotic resistance in Gram-negative bacteria comprises an effective change in the membrane permeability to antibiotics. The Gram-negative bacterial complex cell envelope comprises an outer membrane that delimits the periplasm from the exterior environment. The outer membrane contains numerous protein channels, termed as porins or nanopores, which are mainly involved in the influx of hydrophilic compounds, including antibiotics. Bacterial adaptation to reduce influx through these outer membrane proteins (Omps) is one of the crucial mechanisms behind antibiotic resistance. Thus to interpret the molecular basis of the outer membrane permeability is the current challenge. This review attempts to develop a state of knowledge pertinent to Omps and their effective role in antibiotic influx. Further, it aims to study the bacterial response to antibiotic membrane permeability and hopefully provoke a discussion toward understanding and further exploration of prospects to improve our knowledge on physicochemical parameters that direct the translocation of antibiotics through the bacterial membrane protein channels.
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Affiliation(s)
- Ishan Ghai
- School of Engineering and Life Sciences, Jacobs University, Bremen
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9
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Sanders S, Vierling RJ, Bartee D, DeColli AA, Harrison MJ, Aklinski JL, Koppisch AT, Freel Meyers CL. Challenges and Hallmarks of Establishing Alkylacetylphosphonates as Probes of Bacterial 1-Deoxy-d-xylulose 5-Phosphate Synthase. ACS Infect Dis 2017. [PMID: 28636325 DOI: 10.1021/acsinfecdis.6b00168] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
1-Deoxy-d-xylulose 5-phosphate (DXP) synthase catalyzes the thiamin diphosphate (ThDP)-dependent formation of DXP from pyruvate and d-glyceraldehyde 3-phosphate. DXP is at a metabolic branch point in bacteria, feeding into the methylerythritol phosphate pathway to indispensable isoprenoids and acting as a precursor for biosynthesis of essential cofactors in central metabolism, pyridoxal phosphate and ThDP, the latter of which is also required for DXP synthase catalysis. DXP synthase follows a unique random sequential mechanism and possesses an unusually large active site. These features have guided the design of sterically demanding alkylacetylphosphonates (alkylAPs) toward the development of selective DXP synthase inhibitors. alkylAPs studied here display selective, low μM inhibitory activity against DXP synthase. They are weak inhibitors of bacterial growth in standard nutrient rich conditions. However, bacteria are significantly sensitized to most alkylAPs in defined minimal growth medium, with minimal inhibitory concentrations (MICs) ranging from low μM to low mM and influenced by alkyl-chain length. The longest analog (C8) displays the weakest antimicrobial activity and is a substrate for efflux via AcrAB-TolC. The dependence of inhibitor potency on growth environment emphasizes the need for antimicrobial screening conditions that are relevant to the in vivo microbial microenvironment during infection. DXP synthase expression and thiamin supplementation studies offer support for DXP synthase as an intracellular target for some alkylAPs and reveal both the challenges and intriguing aspects of these approaches to study target engagement.
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Affiliation(s)
- Sara Sanders
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Ryan J. Vierling
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - David Bartee
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Alicia A. DeColli
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Mackenzie J. Harrison
- Department
of Chemistry, Northern Arizona University, Flagstaff, Arizona 86011, United States
| | - Joseph L. Aklinski
- Department
of Chemistry, Northern Arizona University, Flagstaff, Arizona 86011, United States
| | - Andrew T. Koppisch
- Department
of Chemistry, Northern Arizona University, Flagstaff, Arizona 86011, United States
| | - Caren L. Freel Meyers
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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10
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Hartmann M, Gas-Pascual E, Hemmerlin A, Rohmer M, Bach TJ. Development of an image-based screening system for inhibitors of the plastidial MEP pathway and of protein geranylgeranylation. F1000Res 2015; 4:14. [PMID: 26309725 PMCID: PMC4536634 DOI: 10.12688/f1000research.5923.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/31/2015] [Indexed: 03/26/2024] Open
Abstract
In a preceding study we have recently established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, which involves expressing a dexamethasone-inducible GFP fused to the prenylable, carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL). By using pathway-specific inhibitors it was there demonstrated that inhibition of the methylerythritol phosphate (MEP) pathway with oxoclomazone and fosmidomycin, as well as inhibition of protein geranylgeranyl transferase type 1 (PGGT-1), shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA) pathway with mevinolin did not affect this localization. Furthermore, in this initial study complementation assays with pathway-specific intermediates confirmed that the precursors for the cytosolic isoprenylation of this fusion protein are predominantly provided by the MEP pathway. In order to optimize this visualization system from a more qualitative assay to a statistically trustable medium or a high-throughput screening system, we established now new conditions that permit culture and analysis in 96-well microtiter plates, followed by fluorescence microscopy. For further refinement, the existing GFP-BD-CVIL cell line was transformed with an estradiol-inducible vector driving the expression of a RFP protein, C-terminally fused to a nuclear localization signal (NLS-RFP). We are thus able to quantify the total number of viable cells versus the number of inhibited cells after various treatments. This approach also includes a semi-automatic counting system, based on the freely available image processing software. As a result, the time of image analysis as well as the risk of user-generated bias is reduced to a minimum. Moreover, there is no cross-induction of gene expression by dexamethasone and estradiol, which is an important prerequisite for this test system.
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Affiliation(s)
- Michael Hartmann
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Department Biologie, Institut für Molekulare Ökophysiologie der Pflanzen, Universität Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Elisabet Gas-Pascual
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Horticulture and Crop Science, Ohio State University, 208 Williams Hall, 1680 Madison Avenue, Wooster, OH, 44691, USA
| | - Andrea Hemmerlin
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
| | - Michel Rohmer
- UMR 7177 CNRS/Université de Strasbourg, Institut Le Bel, 4 rue Blaise Pascal, F-67070 Strasbourg, France
| | - Thomas J. Bach
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
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11
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Abstract
The dramatic rise in microbial drug resistance in recent years has led to ongoing searches for novel drugs to add to the armory against infectious disease. Nevertheless, a paucity of new antibacterial drugs in discovery and development pipelines using traditional approaches has prompted a variety of unconventional and disruptive strategies for antibacterial drug discovery. Herein, we review recent nontraditional approaches that have been piloted for early drug discovery efforts. These unique methodologies open new avenues for finding the next generation of antimicrobials.
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Affiliation(s)
- Maya A Farha
- M.G. DeGroote Institute for Infectious Disease Research, and Department of Biochemistry and Biomedical Sciences, McMaster University, Ontario, Canada
| | - Eric D Brown
- M.G. DeGroote Institute for Infectious Disease Research, and Department of Biochemistry and Biomedical Sciences, McMaster University, Ontario, Canada
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12
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Hartmann M, Gas-Pascual E, Hemmerlin A, Rohmer M, Bach TJ. Development of an image-based screening system for inhibitors of the plastidial MEP pathway and of protein geranylgeranylation. F1000Res 2015; 4:14. [PMID: 26309725 PMCID: PMC4536634 DOI: 10.12688/f1000research.5923.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/09/2014] [Indexed: 11/20/2022] Open
Abstract
We have recently established an in vivo visualization system for the geranylgeranylation of proteins in a stably transformed tobacco BY-2 cell line, which involves expressing a dexamethasone-inducible GFP fused to the prenylable, carboxy-terminal basic domain of the rice calmodulin CaM61, which naturally bears a CaaL geranylgeranylation motif (GFP-BD-CVIL). By using pathway-specific inhibitors it was demonstrated that inhibition of the methylerythritol phosphate (MEP) pathway with oxoclomazone and fosmidomycin, as well as inhibition of protein geranylgeranyl transferase type 1 (PGGT-1), shifted the localization of the GFP-BD-CVIL protein from the membrane to the nucleus. In contrast, the inhibition of the mevalonate (MVA) pathway with mevinolin did not affect this localization. Furthermore, complementation assays with pathway-specific intermediates confirmed that the precursors for the cytosolic isoprenylation of this fusion protein are predominantly provided by the MEP pathway. In order to optimize this visualization system from a more qualitative assay to a statistically trustable medium or a high-throughput screening system, we established new conditions that permit culture and analysis in 96-well microtiter plates, followed by fluorescence microscopy. For further refinement, the existing GFP-BD-CVIL cell line was transformed with an estradiol-inducible vector driving the expression of a RFP protein, C-terminally fused to a nuclear localization signal (NLS-RFP). We are thus able to quantify the total number of viable cells versus the number of inhibited cells after various treatments. This approach also includes a semi-automatic counting system, based on the freely available image processing software. As a result, the time of image analysis as well as the risk of user-generated bias is reduced to a minimum. Moreover, there is no cross-induction of gene expression by dexamethasone and estradiol, which is an important prerequisite for this test system.
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Affiliation(s)
- Michael Hartmann
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Department Biologie, Institut für Molekulare Ökophysiologie der Pflanzen, Universität Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Elisabet Gas-Pascual
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
- Current address: Horticulture and Crop Science, Ohio State University, 208 Williams Hall, 1680 Madison Avenue, Wooster, OH, 44691, USA
| | - Andrea Hemmerlin
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
| | - Michel Rohmer
- UMR 7177 CNRS/Université de Strasbourg, Institut Le Bel, 4 rue Blaise Pascal, F-67070 Strasbourg, France
| | - Thomas J. Bach
- Département “Réseaux Métaboliques, Institut de Biologie Moléculaire des Plantes, CNRS UPR 2357, Université de Strasbourg, 28 rue Goethe, F-67083 Strasbourg, France
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