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Kim H, Burkinshaw BJ, Lam LG, Manera K, Dong TG. Identification of Small Molecule Inhibitors of the Pathogen Box against Vibrio cholerae. Microbiol Spectr 2021; 9:e0073921. [PMID: 34937180 PMCID: PMC8694189 DOI: 10.1128/spectrum.00739-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/18/2021] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial resistance (AMR) has become a serious public and economic threat. The rate of bacteria acquiring AMR surpasses the rate of new antibiotics discovery, projecting more deadly AMR infections in the future. The Pathogen Box is an open-source library of drug-like compounds that can be screened for antibiotic activity. We have screened molecules of the Pathogen Box against Vibrio cholerae, the cholera-causing pathogen, and successfully identified two compounds, MMV687807 and MMV675968, that inhibit growth. RNA-seq analyses of V. cholerae after incubation with each compound revealed that both compounds affect cellular functions on multiple levels including carbon metabolism, iron homeostasis, and biofilm formation. In addition, whole-genome sequencing analysis of spontaneous resistance mutants identified an efflux system that confers resistance to MMV687807. We also identified that the dihydrofolate reductase is the likely target of MMV675968 suggesting it acts as an analog of trimethoprim but with a MIC 14-fold lower than trimethoprim in molar concentration. In summary, these two compounds that effectively inhibit V. cholerae and other bacteria may lead to the development of new antibiotics for better treatment of the cholera disease. IMPORTANCE Cholera is a serious infectious disease in tropical regions causing millions of infections annually. Vibrio cholerae, the causative agent of cholera, has gained multi-antibiotic resistance over the years, posing greater threat to public health and current treatment strategies. Here we report two compounds that effectively target the growth of V. cholerae and have the potential to control cholera infection.
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Affiliation(s)
- Haeun Kim
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Brianne J. Burkinshaw
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Linh G. Lam
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Kevin Manera
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Tao G. Dong
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Biochemistry and Molecular Biology, Cumming School of Medicine, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China
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Burkinshaw BJ, Souza SA, Strynadka NCJ. Structural analysis of SepL, an enteropathogenic Escherichia coli type III secretion-system gatekeeper protein. Acta Crystallogr F Struct Biol Commun 2015; 71:1300-8. [PMID: 26457522 DOI: 10.1107/s2053230x15016064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 08/27/2015] [Indexed: 12/26/2022]
Abstract
During infection, enteropathogenic Escherichia coli assembles a complex multi-protein type III secretion system that traverses the bacterial membranes and targets the host cell membrane to directly deliver virulence or effector proteins to the host cytoplasm. As this secretion system is composed of more than 20 proteins, many of which form oligomeric associations, its assembly must be tightly regulated. A protein called the gatekeeper, or SepL, ensures that the secretion of the translocon component, which inserts into the host membrane, occurs before the secretion of effectors. The crystal structure of the gatekeeper SepL was determined and compared with the structures of SepL homologues from other bacterial pathogens in order to identify SepL residues that may be critical for its role in type III secretion-system assembly.
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Affiliation(s)
- Brianne J Burkinshaw
- Department of Biochemistry and Molecular Biology, University of British Columbia, Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Sergio A Souza
- Department of Biochemistry and Molecular Biology, University of British Columbia, Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology, University of British Columbia, Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
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Burkinshaw BJ, Deng W, Lameignère E, Wasney GA, Zhu H, Worrall LJ, Finlay BB, Strynadka NCJ. Structural analysis of a specialized type III secretion system peptidoglycan-cleaving enzyme. J Biol Chem 2015; 290:10406-17. [PMID: 25678709 DOI: 10.1074/jbc.m115.639013] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Indexed: 01/20/2023] Open
Abstract
The Gram-negative bacterium enteropathogenic Escherichia coli uses a syringe-like type III secretion system (T3SS) to inject virulence or "effector" proteins into the cytoplasm of host intestinal epithelial cells. To assemble, the T3SS must traverse both bacterial membranes, as well as the peptidoglycan layer. Peptidoglycan is made of repeating N-acetylmuramic acid and N-acetylglucosamine disaccharides cross-linked by pentapeptides to form a tight mesh barrier. Assembly of many macromolecular machines requires a dedicated peptidoglycan lytic enzyme (PG-lytic enzyme) to locally clear peptidoglycan. Here we have solved the first structure of a T3SS-associated PG-lytic enzyme, EtgA from enteropathogenic E. coli. Unexpectedly, the active site of EtgA has features in common with both lytic transglycosylases and hen egg white lysozyme. Most notably, the β-hairpin region resembles that of lysozyme and contains an aspartate that aligns with lysozyme Asp-52 (a residue critical for catalysis), a conservation not observed in other previously characterized lytic transglycosylase families to which the conserved T3SS enzymes had been presumed to belong. Mutation of the EtgA catalytic glutamate, Glu-42, conserved across lytic transglycosylases and hen egg white lysozyme, and this differentiating aspartate diminishes type III secretion in vivo, supporting its essential role in clearing the peptidoglycan for T3SS assembly. Finally, we show that EtgA forms a 1:1 complex with the building block of the polymerized T3SS inner rod component, EscI, and that this interaction enhances PG-lytic activity of EtgA in vitro, collectively providing the necessary strict localization and regulation of the lytic activity to prevent overall cell lysis.
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Affiliation(s)
- Brianne J Burkinshaw
- From the Department of Biochemistry and Molecular Biology and the Center for Blood Research
| | | | - Emilie Lameignère
- From the Department of Biochemistry and Molecular Biology and the Center for Blood Research
| | - Gregory A Wasney
- From the Department of Biochemistry and Molecular Biology and the Center for Blood Research
| | - Haizhong Zhu
- From the Department of Biochemistry and Molecular Biology and the Center for Blood Research
| | - Liam J Worrall
- From the Department of Biochemistry and Molecular Biology and the Center for Blood Research
| | - B Brett Finlay
- From the Department of Biochemistry and Molecular Biology and the Center for Blood Research, the Michael Smith Laboratories, and the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Natalie C J Strynadka
- From the Department of Biochemistry and Molecular Biology and the Center for Blood Research,
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Burkinshaw BJ, Strynadka NCJ. Assembly and structure of the T3SS. Biochim Biophys Acta 2014; 1843:1649-63. [PMID: 24512838 DOI: 10.1016/j.bbamcr.2014.01.035] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 02/06/2023]
Abstract
The Type III Secretion System (T3SS) is a multi-mega Dalton apparatus assembled from more than twenty components and is found in many species of animal and plant bacterial pathogens. The T3SS creates a contiguous channel through the bacterial and host membranes, allowing injection of specialized bacterial effector proteins directly to the host cell. In this review, we discuss our current understanding of T3SS assembly and structure, as well as highlight structurally characterized Salmonella effectors. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Brianne J Burkinshaw
- Department of Biochemistry and Molecular Biology, Center for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology, Center for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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Burkinshaw BJ, Prehna G, Worrall LJ, Strynadka NCJ. Structure of Salmonella effector protein SopB N-terminal domain in complex with host Rho GTPase Cdc42. J Biol Chem 2012; 287:13348-55. [PMID: 22362774 DOI: 10.1074/jbc.m111.331330] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
SopB is a type III secreted Salmonella effector protein with phosphoinositide phosphatase activity and a distinct GTPase binding domain. The latter interacts with host Cdc42, an essential Rho GTPase that regulates critical events in eukaryotic cytoskeleton organization and membrane trafficking. Structural and biochemical analysis of the SopB GTPase binding domain in complex with Cdc42 shows for the first time that SopB structurally and functionally mimics a host guanine nucleotide dissociation inhibitor (GDI) by contacting key residues in the regulatory switch regions of Cdc42 and slowing Cdc42 nucleotide exchange.
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Affiliation(s)
- Brianne J Burkinshaw
- Department of Biochemistry and Molecular Biology and Center for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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