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Ruijgrok G, Wu DY, Overkleeft HS, Codée JDC. Synthesis and application of bacterial exopolysaccharides. Curr Opin Chem Biol 2024; 78:102418. [PMID: 38134611 DOI: 10.1016/j.cbpa.2023.102418] [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: 11/10/2023] [Revised: 12/02/2023] [Accepted: 12/03/2023] [Indexed: 12/24/2023]
Abstract
Exopolysaccharides are produced and excreted by bacteria in the generation of biofilms to provide a protective environment. These polysaccharides are generally generated as heterogeneous polymers of varying length, featuring diverse substitution patterns. To obtain well-defined fragments of these polysaccharides, organic synthesis often is the method of choice, as it allows for full control over chain length and the installation of a pre-determined substitution pattern. This review presents several recent syntheses of exopolysaccharide fragments of Pseudomonas aeruginosa and Staphylococcus aureus and illustrates how these have been used to study biosynthesis enzymes and generate synthetic glycoconjugate vaccines.
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Affiliation(s)
- Gijs Ruijgrok
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333, CC Leiden, the Netherlands
| | - Dung-Yeh Wu
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333, CC Leiden, the Netherlands
| | - Herman S Overkleeft
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333, CC Leiden, the Netherlands
| | - Jeroen D C Codée
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333, CC Leiden, the Netherlands.
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2
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Low KE, Gheorghita AA, Tammam SD, Whitfield GB, Li YE, Riley LM, Weadge JT, Caldwell SJ, Chong PA, Walvoort MTC, Kitova EN, Klassen JS, Codée JDC, Howell PL. Pseudomonas aeruginosa AlgF is a protein-protein interaction mediator required for acetylation of the alginate exopolysaccharide. J Biol Chem 2023; 299:105314. [PMID: 37797696 PMCID: PMC10641220 DOI: 10.1016/j.jbc.2023.105314] [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: 07/26/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/07/2023] Open
Abstract
Enzymatic modifications of bacterial exopolysaccharides enhance immune evasion and persistence during infection. In the Gram-negative opportunistic pathogen Pseudomonas aeruginosa, acetylation of alginate reduces opsonic killing by phagocytes and improves reactive oxygen species scavenging. Although it is well known that alginate acetylation in P. aeruginosa requires AlgI, AlgJ, AlgF, and AlgX, how these proteins coordinate polymer modification at a molecular level remains unclear. Here, we describe the structural characterization of AlgF and its protein interaction network. We characterize direct interactions between AlgF and both AlgJ and AlgX in vitro and demonstrate an association between AlgF and AlgX, as well as AlgJ and AlgI, in P. aeruginosa. We determine that AlgF does not exhibit acetylesterase activity and is unable to bind to polymannuronate in vitro. Therefore, we propose that AlgF functions to mediate protein-protein interactions between alginate acetylation enzymes, forming the periplasmic AlgJFXK (AlgJ-AlgF-AlgX-AlgK) acetylation and export complex required for robust biofilm formation.
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Affiliation(s)
- Kristin E Low
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andreea A Gheorghita
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Stephanie D Tammam
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gregory B Whitfield
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Yancheng E Li
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Laura M Riley
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Joel T Weadge
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shane J Caldwell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - P Andrew Chong
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Elena N Kitova
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - John S Klassen
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jeroen D C Codée
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - P Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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3
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Razvi E, DiFrancesco BR, Wasney GA, Morrison ZA, Tam J, Auger A, Baker P, Alnabelseya N, Rich JD, Sivarajah P, Whitfield GB, Harrison JJ, Melnyk RA, Nitz M, Howell PL. Small Molecule Inhibition of an Exopolysaccharide Modification Enzyme is a Viable Strategy To Block Pseudomonas aeruginosa Pel Biofilm Formation. Microbiol Spectr 2023; 11:e0029623. [PMID: 37098898 PMCID: PMC10269871 DOI: 10.1128/spectrum.00296-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/03/2023] [Indexed: 04/27/2023] Open
Abstract
Biosynthesis of the Pel exopolysaccharide in Pseudomonas aeruginosa requires all seven genes of the pelABCDEFG operon. The periplasmic modification enzyme PelA contains a C-terminal deacetylase domain that is necessary for Pel-dependent biofilm formation. Herein, we show that extracellular Pel is not produced by a P. aeruginosa PelA deacetylase mutant. This positions PelA deacetylase activity as an attractive target to prevent Pel-dependent biofilm formation. Using a high-throughput screen (n = 69,360), we identified 56 compounds that potentially inhibit PelA esterase activity, the first enzymatic step in the deacetylase reaction. A secondary biofilm inhibition assay identified methyl 2-(2-pyridinylmethylene) hydrazinecarbodithioate (SK-017154-O) as a specific Pel-dependent biofilm inhibitor. Structure-activity relationship studies identified the thiocarbazate as a necessary functional group and that the pyridyl ring could be replaced with a phenyl substituent (compound 1). Both SK-017154-O and compound 1 inhibit Pel-dependent biofilm formation in Bacillus cereus ATCC 10987, which has a predicted extracellular PelA deacetylase in its pel operon. Michaelis-Menten kinetics determined SK-017154-O to be a noncompetitive inhibitor of PelA, while compound 1 did not directly inhibit PelA esterase activity. Cytotoxicity assays using human lung fibroblast cells showed that compound 1 is less cytotoxic than SK-017154-O. This work provides proof of concept that biofilm exopolysaccharide modification enzymes are important for biofilm formation and can serve as useful antibiofilm targets. IMPORTANCE Present in more than 500 diverse Gram-negative and 900 Gram-positive organisms, the Pel polysaccharide is one of the most phylogenetically widespread biofilm matrix determinants found to date. Partial de-N-acetylation of this α-1,4 linked N-acetylgalactosamine polymer by the carbohydrate modification enzyme PelA is required for Pel-dependent biofilm formation in Pseudomonas aeruginosa and Bacillus cereus. Given this and our observation that extracellular Pel is not produced by a P. aeruginosa PelA deactylase mutant, we developed an enzyme-based high-throughput screen and identified methyl 2-(2-pyridinylmethylene) hydrazinecarbodithioate (SK-017154-O) and its phenyl derivative as specific Pel-dependent biofilm inhibitors. Michaelis-Menten kinetics revealed SK-017154-O is a noncompetitive inhibitor and that its noncytotoxic, phenyl derivative does not directly inhibit P. aeruginosa PelA esterase activity. We provide proof of concept that exopolysaccharide modification enzymes can be targeted with small molecule inhibitors to block Pel-dependent biofilm development in both Gram-negative and Gram-positive bacteria.
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Affiliation(s)
- Erum Razvi
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | | | - Gregory A. Wasney
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- The Structural & Biophysical Core Facility, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - John Tam
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Anick Auger
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- SPARC BioCentre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Perrin Baker
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Noor Alnabelseya
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jacquelyn D. Rich
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Piyanka Sivarajah
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gregory B. Whitfield
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Joe J. Harrison
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Roman A. Melnyk
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Mark Nitz
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - P. Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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4
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Seegers CII, Lee DJ, Zarnovican P, Kirsch SH, Müller R, Haselhorst T, Routier FH. Identification of Compounds Preventing A. fumigatus Biofilm Formation by Inhibition of the Galactosaminogalactan Deacetylase Agd3. Int J Mol Sci 2023; 24:ijms24031851. [PMID: 36768176 PMCID: PMC9915216 DOI: 10.3390/ijms24031851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/19/2023] Open
Abstract
The opportunistic fungus Aspergillus fumigatus causes a set of diseases ranging from allergy to lethal invasive mycosis. Within the human airways, A. fumigatus is embedded in a biofilm that forms not only a barrier against the host immune defense system, but also creates a physical barrier protecting the fungi from chemicals such as antifungal drugs. Novel therapeutic strategies aim at combining drugs that inhibit biofilm synthesis or disrupt existing biofilm with classical antimicrobials. One of the major constituents of A. fumigatus biofilm is the polysaccharide galactosaminogalactan (GAG) composed of α1,4-linked N-acetylgalactosamine, galactosamine, and galactose residues. GAG is synthesized on the cytosolic face of the plasma membrane and is extruded in the extracellular space, where it is partially deacetylated. The deacetylase Agd3 that mediates this last step is essential for the biofilm formation and full virulence of the fungus. In this work, a previously described enzyme-linked lectin assay, based on the adhesion of deacetylated GAG to negatively charged plates and quantification with biotinylated soybean agglutinin was adapted to screen microbial natural compounds, as well as compounds identified in in silico screening of drug libraries. Actinomycin X2, actinomycin D, rifaximin, and imatinib were shown to inhibit Agd3 activity in vitro. At a concentration of 100 µM, actinomycin D and imatinib showed a clear reduction in the biofilm biomass without affecting the fungal growth. Finally, imatinib reduced the virulence of A. fumigatus in a Galleria mellonella infection model in an Agd3-dependent manner.
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Affiliation(s)
- Carla I. I. Seegers
- Institute for Clinical Biochemistry, OE4340, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Danielle J. Lee
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Patricia Zarnovican
- Institute for Clinical Biochemistry, OE4340, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Susanne H. Kirsch
- Department of Microbial Natural Products, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research, Saarland University Campus, 66123 Saarbrücken, Germany
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 38124 Braunschweig, Germany
| | - Rolf Müller
- Department of Microbial Natural Products, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research, Saarland University Campus, 66123 Saarbrücken, Germany
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 38124 Braunschweig, Germany
- Department of Pharmacy, Saarland University, 66123 Saarbrücken, Germany
| | - Thomas Haselhorst
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Françoise H. Routier
- Institute for Clinical Biochemistry, OE4340, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
- Correspondence:
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5
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Liu Y, Ahmed S, Fang Y, Chen M, An J, Yang G, Hou X, Lu J, Ye Q, Zhu R, Liu Q, Liu S. Discovery of Chitin Deacetylase Inhibitors through Structure-Based Virtual Screening and Biological Assays. J Microbiol Biotechnol 2022; 32:504-513. [PMID: 35131956 PMCID: PMC9628821 DOI: 10.4014/jmb.2201.01009] [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: 01/11/2022] [Revised: 01/30/2022] [Accepted: 02/03/2022] [Indexed: 12/15/2022]
Abstract
Chitin deacetylase (CDA) inhibitors were developed as novel antifungal agents because CDA participates in critical fungal physiological and metabolic processes and increases virulence in soilborne fungal pathogens. However, few CDA inhibitors have been reported. In this study, 150 candidate CDA inhibitors were selected from the commercial Chemdiv compound library through structure-based virtual screening. The top-ranked 25 compounds were further evaluated for biological activity. The compound J075-4187 had an IC50 of 4.24 ± 0.16 μM for AnCDA. Molecular docking calculations predicted that compound J075-4187 binds to the amino acid residues, including active sites (H101, D48). Furthermore, compound J075-4187 inhibited food spoilage fungi and plant pathogenic fungi, with minimum inhibitory concentration (MIC) at 260 μg/ml and minimum fungicidal concentration (MFC) at 520 μg/ml. Therefore, compound J075-4187 is a good candidate for use in developing antifungal agents for fungi control.
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Affiliation(s)
- Yaodong Liu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China
| | - Sibtain Ahmed
- University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Yaowei Fang
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China,Jiangsu Marine Resources Development Research Institute, Jiangsu Ocean University, Lianyungang 222000, P.R. China
| | - Meng Chen
- Lianyungang Inspection and Testing Center for Food and Drug Control, P.R. China
| | - Jia An
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China
| | - Guang Yang
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China
| | - Xiaoyue Hou
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China
| | - Jing Lu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China
| | - Qinwen Ye
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China
| | - Rongjun Zhu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China
| | - Qitong Liu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China
| | - Shu Liu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, P.R. China,Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, P.R. China,Corresponding author E-mail:
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6
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Anderson AC, Burnett AJN, Constable S, Hiscock L, Maly KE, Weadge JT. A Mechanistic Basis for Phosphoethanolamine Modification of the Cellulose Biofilm Matrix in Escherichia coli. Biochemistry 2021; 60:3659-3669. [PMID: 34762795 DOI: 10.1021/acs.biochem.1c00605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biofilms are communities of self-enmeshed bacteria in a matrix of exopolysaccharides. The widely distributed human pathogen and commensal Escherichia coli produces a biofilm matrix composed of phosphoethanolamine (pEtN)-modified cellulose and amyloid protein fibers, termed curli. The addition of pEtN to the cellulose exopolysaccharide is accomplished by the action of the pEtN transferase, BcsG, and is essential for the overall integrity of the biofilm. Here, using the synthetic co-substrates p-nitrophenyl phosphoethanolamine and β-d-cellopentaose, we demonstrate using an in vitro pEtN transferase assay that full activity of the pEtN transferase domain of BcsG from E. coli (EcBcsGΔN) requires Zn2+ binding, a catalytic nucleophile/acid-base arrangement (Ser278/Cys243/His396), disulfide bond formation, and other newly uncovered essential residues. We further confirm that EcBcsGΔN catalysis proceeds by a ping-pong bisubstrate-biproduct reaction mechanism and displays inefficient kinetic behavior (kcat/KM = 1.81 × 10-4 ± 2.81 × 10-5 M-1 s-1), which is typical of exopolysaccharide-modifying enzymes in bacteria. Thus, the results presented, especially with respect to donor binding (as reflected by KM), have importantly broadened our understanding of the substrate profile and catalytic mechanism of this class of enzymes, which may aid in the development of inhibitors targeting BcsG or other characterized members of the pEtN transferase family, including the intrinsic and mobile colistin resistance factors.
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7
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Forman A, Pfoh R, Eddenden A, Howell PL, Nitz M. Synthesis of defined mono-de-N-acetylated β-(1→6)-N-acetyl-d-glucosamine oligosaccharides to characterize PgaB hydrolase activity. Org Biomol Chem 2019; 17:9456-9466. [PMID: 31642455 DOI: 10.1039/c9ob02079a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Many clinically-relevant biofilm-forming bacterial strains produce partially de-N-acetylated poly-β-(1→6)-N-acetyl-d-glucosamine (dPNAG) as an exopolysaccharide. In Gram-negative bacteria, the periplasmic protein PgaB is responsible for partial de-N-acetylation of PNAG prior to its export to the extracellular space. In addition to de-N-acetylase activity found in the N-terminal domain, PgaB contains a C-terminal hydrolase domain that can disrupt dPNAG-dependent biofilms and hydrolyzes dPNAG but not fully acetylated PNAG. The role of this C-terminal domain in biofilm formation has yet to be determined in vivo. Further characterization of the enzyme's hydrolase activity has been hampered by a lack of specific dPNAG oligosaccharides. Here, we report the synthesis of a defined mono de-N-acetylated dPNAG penta- and hepta-saccharide. Using mass spectrometry analysis and a fluorescence-based thin-layer chromatography (TLC) assay, we found that our defined dPNAG oligosaccharides are hydrolase substrates. In addition to the expected cleavage site, two residues to the reducing side of the de-N-acetylated residue, minor cleavage products on the non-reducing side of the de-N-acetylation site were observed. These findings provide quantitative data to support how PNAG is processed in Gram-negative bacteria.
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Affiliation(s)
- Adam Forman
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, Canada M5S 3H6.
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8
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Igual MO, Nunes PS, da Costa RM, Mantoani SP, Tostes RC, Carvalho I. Novel glucopyranoside C2-derived 1,2,3-triazoles displaying selective inhibition of O-GlcNAcase (OGA). Carbohydr Res 2019; 471:43-55. [DOI: 10.1016/j.carres.2018.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/19/2018] [Accepted: 10/22/2018] [Indexed: 01/13/2023]
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9
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Ostapska H, Howell PL, Sheppard DC. Deacetylated microbial biofilm exopolysaccharides: It pays to be positive. PLoS Pathog 2018; 14:e1007411. [PMID: 30589915 PMCID: PMC6307706 DOI: 10.1371/journal.ppat.1007411] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Hanna Ostapska
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Infectious Diseases in Global Health Program, McGill University Health Centre, Montreal, Quebec, Canada
| | - P. Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- * E-mail: (PLH); (DCS)
| | - Donald C. Sheppard
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Infectious Diseases in Global Health Program, McGill University Health Centre, Montreal, Quebec, Canada
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- * E-mail: (PLH); (DCS)
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10
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DiFrancesco BR, Morrison ZA, Nitz M. Monosaccharide inhibitors targeting carbohydrate esterase family 4 de-N-acetylases. Bioorg Med Chem 2018; 26:5631-5643. [PMID: 30344002 DOI: 10.1016/j.bmc.2018.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/03/2018] [Accepted: 10/11/2018] [Indexed: 12/21/2022]
Abstract
The Carbohydrate Esterase family 4 contains virulence factors which modify peptidoglycan and biofilm-related exopolysaccharides. Despite the importance of this family of enzymes, a potent mechanism-based inhibition strategy has yet to emerge. Based on the postulated tridentate binding mode of the tetrahedral de-N-acetylation intermediate, GlcNAc derivatives bearing metal chelating groups at the 2 and 3 positions were synthesized. These scaffolds include 2-C phosphonate, 2-C sulfonamide, 2-thionoacetamide warheads as well as derivatives bearing thiol, amine and azide substitutions at the 3-position. The inhibitors were assayed against a representative peptidoglycan deacetylase, Pgda from Streptococcus pneumonia, and a representative biofilm-related exopolysaccharide deacetylase, PgaB from Escherichia coli. Of the inhibitors evaluated, the 3-thio derivatives showed weak to moderate inhibition of Pgda. The strongest inhibitor was benzyl 2,3-dideoxy-2-thionoacetamide-3-thio-β-d-glucoside, whose inhibitory potency showed an unexpected dependence on metal concentration and was found to have a partial mixed inhibition mode (Ki = 2.9 ± 0.6 μM).
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Affiliation(s)
| | - Zachary A Morrison
- Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada
| | - Mark Nitz
- Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada.
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11
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Coullon H, Rifflet A, Wheeler R, Janoir C, Boneca IG, Candela T. N-Deacetylases required for muramic-δ-lactam production are involved in Clostridium difficile sporulation, germination, and heat resistance. J Biol Chem 2018; 293:18040-18054. [PMID: 30266804 DOI: 10.1074/jbc.ra118.004273] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/24/2018] [Indexed: 01/08/2023] Open
Abstract
Spores are produced by many organisms as a survival mechanism activated in response to several environmental stresses. Bacterial spores are multilayered structures, one of which is a peptidoglycan layer called the cortex, containing muramic-δ-lactams that are synthesized by at least two bacterial enzymes, the muramoyl-l-alanine amidase CwlD and the N-deacetylase PdaA. This study focused on the spore cortex of Clostridium difficile, a Gram-positive, toxin-producing anaerobic bacterial pathogen that can colonize the human intestinal tract and is a leading cause of antibiotic-associated diarrhea. Using ultra-HPLC coupled with high-resolution MS, here we found that the spore cortex of the C. difficile 630Δerm strain differs from that of Bacillus subtilis Among these differences, the muramic-δ-lactams represented only 24% in C. difficile, compared with 50% in B. subtilis CD630_14300 and CD630_27190 were identified as genes encoding the C. difficile N-deacetylases PdaA1 and PdaA2, required for muramic-δ-lactam synthesis. In a pdaA1 mutant, only 0.4% of all muropeptides carried a muramic-δ-lactam modification, and muramic-δ-lactams were absent in the cortex of a pdaA1-pdaA2 double mutant. Of note, the pdaA1 mutant exhibited decreased sporulation, altered germination, decreased heat resistance, and delayed virulence in a hamster infection model. These results suggest a much greater role for muramic-δ-lactams in C. difficile than in other bacteria, including B. subtilis In summary, the spore cortex of C. difficile contains lower levels of muramic-δ-lactams than that of B. subtilis, and PdaA1 is the major N-deacetylase for muramic-δ-lactam biosynthesis in C. difficile, contributing to sporulation, heat resistance, and virulence.
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Affiliation(s)
- Héloise Coullon
- From the EA4043 Unité Bactéries Pathogènes et Santé (UBaPS), Université Paris-Sud, Université Paris-Saclay, 92290 Châtenay-Malabry
| | - Aline Rifflet
- the Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, 75724 Paris, and; INSERM, Équipe Avenir, 75015 Paris, France
| | - Richard Wheeler
- the Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, 75724 Paris, and; INSERM, Équipe Avenir, 75015 Paris, France
| | - Claire Janoir
- From the EA4043 Unité Bactéries Pathogènes et Santé (UBaPS), Université Paris-Sud, Université Paris-Saclay, 92290 Châtenay-Malabry
| | - Ivo Gomperts Boneca
- the Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, 75724 Paris, and; INSERM, Équipe Avenir, 75015 Paris, France
| | - Thomas Candela
- From the EA4043 Unité Bactéries Pathogènes et Santé (UBaPS), Université Paris-Sud, Université Paris-Saclay, 92290 Châtenay-Malabry,.
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12
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Substrate Recognition and Specificity of Chitin Deacetylases and Related Family 4 Carbohydrate Esterases. Int J Mol Sci 2018; 19:ijms19020412. [PMID: 29385775 PMCID: PMC5855634 DOI: 10.3390/ijms19020412] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 01/22/2018] [Accepted: 01/24/2018] [Indexed: 12/27/2022] Open
Abstract
Carbohydrate esterases family 4 (CE4 enzymes) includes chitin and peptidoglycan deacetylases, acetylxylan esterases, and poly-N-acetylglucosamine deacetylases that act on structural polysaccharides, altering their physicochemical properties, and participating in diverse biological functions. Chitin and peptidoglycan deacetylases are not only involved in cell wall morphogenesis and remodeling in fungi and bacteria, but they are also used by pathogenic microorganisms to evade host defense mechanisms. Likewise, biofilm formation in bacteria requires partial deacetylation of extracellular polysaccharides mediated by poly-N-acetylglucosamine deacetylases. Such biological functions make these enzymes attractive targets for drug design against pathogenic fungi and bacteria. On the other side, acetylxylan esterases deacetylate plant cell wall complex xylans to make them accessible to hydrolases, making them attractive biocatalysts for biomass utilization. CE4 family members are metal-dependent hydrolases. They are highly specific for their particular substrates, and show diverse modes of action, exhibiting either processive, multiple attack, or patterned deacetylation mechanisms. However, the determinants of substrate specificity remain poorly understood. Here, we review the current knowledge on the structure, activity, and specificity of CE4 enzymes, focusing on chitin deacetylases and related enzymes active on N-acetylglucosamine-containing oligo and polysaccharides.
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13
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Parthiban C, Varudharasu D, Shanmugam M, Gopal P, Ragunath C, Thomas L, Nitz M, Ramasubbu N. Structural and functional analysis of de-N-acetylase PgaB from periodontopathogenAggregatibacter actinomycetemcomitans. Mol Oral Microbiol 2016; 32:324-340. [DOI: 10.1111/omi.12175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2016] [Indexed: 01/09/2023]
Affiliation(s)
- C. Parthiban
- Department of Oral Biology; Rutgers School of Dental Medicine; Newark NJ USA
| | - D. Varudharasu
- Selvam Structure Based Drug Design Laboratory; Selvam College of Technology; Namakkal Tamilnadu India
| | - M. Shanmugam
- Department of Oral Biology; Rutgers School of Dental Medicine; Newark NJ USA
| | - P. Gopal
- Department of Oral Biology; Rutgers School of Dental Medicine; Newark NJ USA
| | - C. Ragunath
- Scientific Chemical Technologies; Malden MA USA
| | - L. Thomas
- Department of Chemistry and Biochemistry; University of Oklahoma; Norman OK USA
| | - M. Nitz
- Department of Chemistry; University of Toronto; Toronto ON Canada
| | - N. Ramasubbu
- Department of Oral Biology; Rutgers School of Dental Medicine; Newark NJ USA
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14
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Ariyakumaran R, Pokrovskaya V, Little DJ, Howell PL, Nitz M. Direct Staudinger-Phosphonite Reaction Provides Methylphosphonamidates as Inhibitors of CE4 De-N-acetylases. Chembiochem 2015; 16:1350-6. [PMID: 25864869 DOI: 10.1002/cbic.201500091] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Indexed: 11/09/2022]
Abstract
De-N-acetylases of β-(1→6)-D-N-acetylglucosamine polymers (PNAG) and β-(1→4)-D-N-acetylglucosamine residues in peptidoglycan are attractive targets for antimicrobial agents. PNAG de-N-acetylases are necessary for biofilm formation in numerous pathogenic bacteria. Peptidoglycan de-N-acetylation facilitates bacterial evasion of innate immune defenses. To target these enzymes, transition-state analogue inhibitors containing a methylphosphonamidate have been synthesized through a direct Staudinger-phosphonite reaction. The inhibitors were tested on purified PgaB, a PNAG de-N-acetylase from Escherichia coli, and PgdA, a peptidoglycan de-N-acetylase from Streptococcus pneumonia. Herein, we describe the most potent inhibitor of peptidoglycan de-N-acetylases reported to date (Ki =80 μM). The minimal inhibition of PgaB observed provides insight into key structural and functional differences in these enzymes that will need to be considered during the development of future inhibitors.
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Affiliation(s)
- Rishikesh Ariyakumaran
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 (Canada)
| | - Varvara Pokrovskaya
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 (Canada)
| | - Dustin J Little
- Program in Molecular Structure and Function, The Hospital for Sick Children and Department of Biochemistry, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8 (Canada)
| | - P Lynne Howell
- Program in Molecular Structure and Function, The Hospital for Sick Children and Department of Biochemistry, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8 (Canada)
| | - Mark Nitz
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 (Canada).
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15
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Pokrovskaya V, Poloczek J, Little DJ, Griffiths H, Howell PL, Nitz M. Functional characterization of Staphylococcus epidermidis IcaB, a de-N-acetylase important for biofilm formation. Biochemistry 2013; 52:5463-71. [PMID: 23866051 DOI: 10.1021/bi400836g] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A polymer of partially de-N-acetylated β-1,6-linked N-acetylglucosamine (dPNAG), also known as the polysaccharide intercellular adhesin (PIA), is an important component of many bacterial biofilm matrices. In Staphyloccocus epidermidis, the poly-N-acetylglucosamine polymer is partially de-N-acetylated by the extracellular protein IcaB. To understand the mechanism of action of IcaB, the enzyme was overexpressed and purified. IcaB demonstrates metal-dependent de-N-acetylase activity on β-1,6-linked N-acetylglucosamine oligomers with a broad preference for divalent metals. Steady-state kinetic analysis reveals the low catalytic efficiency (pentasaccharide kcat/KM 0.03 M(-1) s(-1)) of the enzyme toward the oligomeric substrates. While IcaB displays similar rates of de-N-acetylation with tri- through hexasaccharide PNAG oligomers, position specific de-N-acetylation was only observed with penta- and hexasaccharides. The enzyme preferentially de-N-acetylates the second residue from the reducing terminus in the pentasaccharide and second and third residues from the reducing terminus in the hexasaccharide. The data described here represent an important step toward a detailed understanding of dPNAG biosynthesis in S. epidermidis, an important nosocomial pathogen, as well as in other Gram-positive bacteria. The low catalytic activity of IcaB is consistent with reports of other enzymes which act on biofilm-related polysaccharides, and this emerging trend may indicate a common feature among this group of polysaccharide processing enzymes.
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Affiliation(s)
- Varvara Pokrovskaya
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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16
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Riley LM, Weadge JT, Baker P, Robinson H, Codée JDC, Tipton PA, Ohman DE, Howell PL. Structural and functional characterization of Pseudomonas aeruginosa AlgX: role of AlgX in alginate acetylation. J Biol Chem 2013; 288:22299-314. [PMID: 23779107 DOI: 10.1074/jbc.m113.484931] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The exopolysaccharide alginate, produced by mucoid Pseudomonas aeruginosa in the lungs of cystic fibrosis patients, undergoes two different chemical modifications as it is synthesized that alter the properties of the polymer and hence the biofilm. One modification, acetylation, causes the cells in the biofilm to adhere better to lung epithelium, form microcolonies, and resist the effects of the host immune system and/or antibiotics. Alginate biosynthesis requires 12 proteins encoded by the algD operon, including AlgX, and although this protein is essential for polymer production, its exact role is unknown. In this study, we present the X-ray crystal structure of AlgX at 2.15 Å resolution. The structure reveals that AlgX is a two-domain protein, with an N-terminal domain with structural homology to members of the SGNH hydrolase superfamily and a C-terminal carbohydrate-binding module. A number of residues in the carbohydrate-binding module form a substrate recognition "pinch point" that we propose aids in alginate binding and orientation. Although the topology of the N-terminal domain deviates from canonical SGNH hydrolases, the residues that constitute the Ser-His-Asp catalytic triad characteristic of this family are structurally conserved. In vivo studies reveal that site-specific mutation of these residues results in non-acetylated alginate. This catalytic triad is also required for acetylesterase activity in vitro. Our data suggest that not only does AlgX protect the polymer as it passages through the periplasm but that it also plays a role in alginate acetylation. Our results provide the first structural insight for a wide group of closely related bacterial polysaccharide acetyltransferases.
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Affiliation(s)
- Laura M Riley
- Program in Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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Guy L, Jernberg C, Arvén Norling J, Ivarsson S, Hedenström I, Melefors Ö, Liljedahl U, Engstrand L, Andersson SGE. Adaptive mutations and replacements of virulence traits in the Escherichia coli O104:H4 outbreak population. PLoS One 2013; 8:e63027. [PMID: 23675451 PMCID: PMC3651199 DOI: 10.1371/journal.pone.0063027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 03/27/2013] [Indexed: 12/15/2022] Open
Abstract
The sequencing of highly virulent Escherichia coli O104:H4 strains isolated during the outbreak of bloody diarrhea and hemolytic uremic syndrome in Europe in 2011 revealed a genome that contained a Shiga toxin encoding prophage and a plasmid encoding enteroaggregative fimbriae. Here, we present the draft genome sequence of a strain isolated in Sweden from a patient who had travelled to Tunisia in 2010 (E112/10) and was found to differ from the outbreak strains by only 38 SNPs in non-repetitive regions, 16 of which were mapped to the branch to the outbreak strain. We identified putatively adaptive mutations in genes for transporters, outer surface proteins and enzymes involved in the metabolism of carbohydrates. A comparative analysis with other historical strains showed that E112/10 contained Shiga toxin prophage genes of the same genotype as the outbreak strain, while these genes have been replaced by a different genotype in two otherwise very closely related strains isolated in the Republic of Georgia in 2009. We also present the genome sequences of two enteroaggregative E. coli strains affiliated with phylogroup A (C43/90 and C48/93) that contain the agg genes for the AAF/I-type fimbriae characteristic of the outbreak population. Interestingly, C43/90 also contained a tet/mer antibiotic resistance island that was nearly identical in sequence to that of the outbreak strain, while the corresponding island in the Georgian strains was most similar to E. coli strains of other serotypes. We conclude that the pan-genome of the outbreak population is shared with strains of the A phylogroup and that its evolutionary history is littered with gene replacement events, including most recently independent acquisitions of antibiotic resistance genes in the outbreak strains and its nearest neighbors. The results are summarized in a refined evolutionary model for the emergence of the O104:H4 outbreak population.
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Affiliation(s)
- Lionel Guy
- Department of Molecular Evolution, Cell and Molecular Biology, Science for Life Laboratory, Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Cecilia Jernberg
- Department of Preparedness, Swedish Institute for Communicable Disease Control, Solna, Sweden
| | - Jenny Arvén Norling
- Department of Molecular Evolution, Cell and Molecular Biology, Science for Life Laboratory, Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Sofie Ivarsson
- Department of Preparedness, Swedish Institute for Communicable Disease Control, Solna, Sweden
| | - Ingela Hedenström
- Department of Preparedness, Swedish Institute for Communicable Disease Control, Solna, Sweden
| | - Öjar Melefors
- Department of Preparedness, Swedish Institute for Communicable Disease Control, Solna, Sweden
- Department of Microbiology, Tumor- and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Ulrika Liljedahl
- Department of Medical Sciences, Molecular Medicine, Uppsala University, Uppsala, Sweden
| | - Lars Engstrand
- Department of Preparedness, Swedish Institute for Communicable Disease Control, Solna, Sweden
- Department of Microbiology, Tumor- and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Siv G. E. Andersson
- Department of Molecular Evolution, Cell and Molecular Biology, Science for Life Laboratory, Biomedical Centre, Uppsala University, Uppsala, Sweden
- * E-mail:
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