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Gheorghita AA, Li YE, Kitova EN, Bui DT, Pfoh R, Low KE, Whitfield GB, Walvoort MTC, Zhang Q, Codée JDC, Klassen JS, Howell PL. Structure of the AlgKX modification and secretion complex required for alginate production and biofilm attachment in Pseudomonas aeruginosa. Nat Commun 2022; 13:7631. [PMID: 36494359 PMCID: PMC9734138 DOI: 10.1038/s41467-022-35131-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 11/18/2022] [Indexed: 12/13/2022] Open
Abstract
Synthase-dependent secretion systems are a conserved mechanism for producing exopolysaccharides in Gram-negative bacteria. Although widely studied, it is not well understood how these systems are organized to coordinate polymer biosynthesis, modification, and export across both membranes and the peptidoglycan. To investigate how synthase-dependent secretion systems produce polymer at a molecular level, we determined the crystal structure of the AlgK-AlgX (AlgKX) complex involved in Pseudomonas aeruginosa alginate exopolysaccharide acetylation and export. We demonstrate that AlgKX directly binds alginate oligosaccharides and that formation of the complex is vital for polymer production and biofilm attachment. Finally, we propose a structural model for the AlgEKX outer membrane modification and secretion complex. Together, our study provides insight into how alginate biosynthesis proteins coordinate production of a key exopolysaccharide involved in establishing persistent Pseudomonas lung infections.
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Affiliation(s)
- Andreea A. Gheorghita
- grid.42327.300000 0004 0473 9646Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Department of Biochemistry, University of Toronto, Toronto, ON Canada
| | - Yancheng E. Li
- grid.42327.300000 0004 0473 9646Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Department of Biochemistry, University of Toronto, Toronto, ON Canada ,grid.20861.3d0000000107068890Present Address: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA USA
| | - Elena N. Kitova
- grid.17089.370000 0001 2190 316XDepartment of Chemistry, University of Alberta, Edmonton, AB Canada
| | - Duong T. Bui
- grid.17089.370000 0001 2190 316XDepartment of Chemistry, University of Alberta, Edmonton, AB Canada
| | - Roland Pfoh
- grid.42327.300000 0004 0473 9646Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON Canada
| | - Kristin E. Low
- grid.42327.300000 0004 0473 9646Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON Canada ,grid.55614.330000 0001 1302 4958Present Address: Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB Canada
| | - Gregory B. Whitfield
- grid.42327.300000 0004 0473 9646Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Department of Biochemistry, University of Toronto, Toronto, ON Canada ,grid.14848.310000 0001 2292 3357Present Address: Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, QC Canada
| | - Marthe T. C. Walvoort
- grid.5132.50000 0001 2312 1970Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands ,grid.4830.f0000 0004 0407 1981Present Address: Department of Chemical Biology, Stratingh Institute for Chemistry, University of Groningen, Groningen, The Netherlands
| | - Qingju Zhang
- grid.5132.50000 0001 2312 1970Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands ,grid.411862.80000 0000 8732 9757Present Address: National Research Centre for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang, China
| | - Jeroen D. C. Codée
- grid.5132.50000 0001 2312 1970Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - John S. Klassen
- grid.17089.370000 0001 2190 316XDepartment of Chemistry, University of Alberta, Edmonton, AB Canada
| | - P. Lynne Howell
- grid.42327.300000 0004 0473 9646Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Department of Biochemistry, University of Toronto, Toronto, ON Canada
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2
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Gheorghita AA, Wolfram F, Whitfield GB, Jacobs HM, Pfoh R, Wong SSY, Guitor AK, Goodyear MC, Berezuk AM, Khursigara CM, Parsek MR, Howell PL. The Pseudomonas aeruginosa homeostasis enzyme AlgL clears the periplasmic space of accumulated alginate during polymer biosynthesis. J Biol Chem 2022; 298:101560. [PMID: 34990713 PMCID: PMC8829089 DOI: 10.1016/j.jbc.2021.101560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/27/2021] [Accepted: 12/28/2021] [Indexed: 11/24/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen and a leading cause of chronic infection in the lungs of individuals with cystic fibrosis. After colonization, P. aeruginosa often undergoes a phenotypic conversion to mucoidy, characterized by overproduction of the alginate exopolysaccharide. This conversion is correlated with poorer patient prognoses. The majority of genes required for alginate synthesis, including the alginate lyase, algL, are located in a single operon. Previous investigations of AlgL have resulted in several divergent hypotheses regarding the protein’s role in alginate production. To address these discrepancies, we determined the structure of AlgL and, using multiple sequence alignments, identified key active site residues involved in alginate binding and catalysis. In vitro enzymatic analysis of active site mutants highlights R249 and Y256 as key residues required for alginate lyase activity. In a genetically engineered P. aeruginosa strain where alginate biosynthesis is under arabinose control, we found that AlgL is required for cell viability and maintaining membrane integrity during alginate production. We demonstrate that AlgL functions as a homeostasis enzyme to clear the periplasmic space of accumulated polymer. Constitutive expression of the AlgU/T sigma factor mitigates the effects of an algL deletion during alginate production, suggesting that an AlgU/T-regulated protein or proteins can compensate for an algL deletion. Together, our study demonstrates the role of AlgL in alginate biosynthesis, explains the discrepancies observed previously across other P. aeruginosa ΔalgL genetic backgrounds, and clarifies the existing divergent data regarding the function of AlgL as an alginate degrading enzyme.
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Affiliation(s)
- Andreea A Gheorghita
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Francis Wolfram
- 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
| | - Holly M Jacobs
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington, USA
| | - Roland Pfoh
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Steven S Y Wong
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Allison K Guitor
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mara C Goodyear
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Alison M Berezuk
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Cezar M Khursigara
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - 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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Marmont LS, Whitfield GB, Pfoh R, Williams RJ, Randall TE, Ostaszewski A, Razvi E, Groves RA, Robinson H, Nitz M, Parsek MR, Lewis IA, Whitney JC, Harrison JJ, Howell PL. PelX is a UDP- N-acetylglucosamine C4-epimerase involved in Pel polysaccharide-dependent biofilm formation. J Biol Chem 2020; 295:11949-11962. [PMID: 32601062 PMCID: PMC7443510 DOI: 10.1074/jbc.ra120.014555] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/24/2020] [Indexed: 12/15/2022] Open
Abstract
Pel is a GalNAc-rich bacterial polysaccharide that contributes to the structure and function of Pseudomonas aeruginosa biofilms. The pelABCDEFG operon is highly conserved among diverse bacterial species, and Pel may therefore be a widespread biofilm determinant. Previous annotation of pel gene clusters has helped us identify an additional gene, pelX, that is present adjacent to pelABCDEFG in >100 different bacterial species. The pelX gene is predicted to encode a member of the short-chain dehydrogenase/reductase (SDR) superfamily, but its potential role in Pel-dependent biofilm formation is unknown. Herein, we have used Pseudomonas protegens Pf-5 as a model to elucidate PelX function as Pseudomonas aeruginosa lacks a pelX homologue in its pel gene cluster. We found that P. protegens forms Pel-dependent biofilms; however, despite expression of pelX under these conditions, biofilm formation was unaffected in a ΔpelX strain. This observation led us to identify a pelX paralogue, PFL_5533, which we designate here PgnE, that appears to be functionally redundant to pelX In line with this, a ΔpelX ΔpgnE double mutant was substantially impaired in its ability to form Pel-dependent biofilms. To understand the molecular basis for this observation, we determined the structure of PelX to 2.1 Å resolution. The structure revealed that PelX resembles UDP-GlcNAc C4-epimerases. Using 1H NMR analysis, we show that PelX catalyzes the epimerization between UDP-GlcNAc and UDP-GalNAc. Our results indicate that Pel-dependent biofilm formation requires a UDP-GlcNAc C4-epimerase that generates the UDP-GalNAc precursors required by the Pel synthase machinery for polymer production.
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Affiliation(s)
- Lindsey S Marmont
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, 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
| | - Roland Pfoh
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rohan J Williams
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Trevor E Randall
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | | | - Erum Razvi
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Ryan A Groves
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Howard Robinson
- Photon Science Division, Brookhaven National Laboratory, Upton, New York, USA
| | - Mark Nitz
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Ian A Lewis
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - John C Whitney
- 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
| | - 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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Bojagora A, Gagarina V, Lacdao IK, Luthra N, Pfoh R, Mohseni S, Chaharlangi D, Tan N, Saridakis V. Structural basis of the interaction between ubiquitin specific protease 7 and enhancer of Zeste homolog 2. Acta Crystallogr A Found Adv 2020. [DOI: 10.1107/s0108767320098888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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5
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Gagarina V, Bojagora A, Lacdao IK, Luthra N, Pfoh R, Mohseni S, Chaharlangi D, Tan N, Saridakis V. Structural Basis of the Interaction Between Ubiquitin Specific Protease 7 and Enhancer of Zeste Homolog 2. J Mol Biol 2019; 432:897-912. [PMID: 31866294 DOI: 10.1016/j.jmb.2019.12.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 08/12/2019] [Revised: 11/26/2019] [Accepted: 12/12/2019] [Indexed: 11/25/2022]
Abstract
USP7 is a deubiquitinase that regulates many diverse cellular processes, including tumor suppression, epigenetics, and genome stability. Several substrates, including GMPS, UHRF1, and ICP0, were shown to bear a specific KxxxK motif that interacts within the C-terminal region of USP7. We identified a similar motif in Enhancer of Zeste 2 (EZH2), the histone methyltransferase found within Polycomb Repressive Complex 2 (PRC2). PRC2 is responsible for the methylation of Histone 3 Lys27 (H3K27) leading to gene silencing. GST pull-down and coimmunoprecipitation experiments showed that USP7 interacts with EZH2. We determined the structural basis of interaction between USP7 and EZH2 and identified residues mediating the interaction. Mutations in these critical residues disrupted the interaction between USP7 and EZH2. Furthermore, USP7 silencing and knockout experiments showed decreased EZH2 levels in HCT116 carcinoma cells. Finally, we demonstrated decreased H3K27Me3 levels in HCT116 USP7 knockout cells. These results indicate that USP7 interacts with EZH2 and regulates both its stability and function.
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Affiliation(s)
- Varvara Gagarina
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J1P3, Canada
| | - Anna Bojagora
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J1P3, Canada
| | - Ira Kay Lacdao
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J1P3, Canada
| | - Niharika Luthra
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J1P3, Canada
| | - Roland Pfoh
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J1P3, Canada
| | - Sadaf Mohseni
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J1P3, Canada
| | - Danica Chaharlangi
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J1P3, Canada
| | - Nadine Tan
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J1P3, Canada
| | - Vivian Saridakis
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J1P3, Canada.
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6
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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7
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Pfoh R, Chavoshi S, Lacdao I, Saridakis V. Structural basis of interaction of herpes virus proteins with the deubiquitinase USP7. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s0108767318096563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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8
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Pfoh R, Little DJ, Le Mauff F, Bamford NC, Notte C, Baker P, Guragain M, Robinson H, Pier GB, Nitz M, Deora R, Sheppard DC, Howell PL. Molecular basis for PNAG-dependent biofilm disruption by PgaB. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s0108767318098987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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9
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Little DJ, Pfoh R, Le Mauff F, Bamford NC, Notte C, Baker P, Guragain M, Robinson H, Pier GB, Nitz M, Deora R, Sheppard DC, Howell PL. PgaB orthologues contain a glycoside hydrolase domain that cleaves deacetylated poly-β(1,6)-N-acetylglucosamine and can disrupt bacterial biofilms. PLoS Pathog 2018; 14:e1006998. [PMID: 29684093 PMCID: PMC5933820 DOI: 10.1371/journal.ppat.1006998] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 05/03/2018] [Accepted: 03/29/2018] [Indexed: 11/24/2022] Open
Abstract
Poly-β(1,6)-N-acetyl-D-glucosamine (PNAG) is a major biofilm component of many pathogenic bacteria. The production, modification, and export of PNAG in Escherichia coli and Bordetella species require the protein products encoded by the pgaABCD operon. PgaB is a two-domain periplasmic protein that contains an N-terminal deacetylase domain and a C-terminal PNAG binding domain that is critical for export. However, the exact function of the PgaB C-terminal domain remains unclear. Herein, we show that the C-terminal domains of Bordetella bronchiseptica PgaB (PgaBBb) and E. coli PgaB (PgaBEc) function as glycoside hydrolases. These enzymes hydrolyze purified deacetylated PNAG (dPNAG) from Staphylococcus aureus, disrupt PNAG-dependent biofilms formed by Bordetella pertussis, Staphylococcus carnosus, Staphylococcus epidermidis, and E. coli, and potentiate bacterial killing by gentamicin. Furthermore, we found that PgaBBb was only able to hydrolyze PNAG produced in situ by the E. coli PgaCD synthase complex when an active deacetylase domain was present. Mass spectrometry analysis of the PgaB-hydrolyzed dPNAG substrate showed a GlcN-GlcNAc-GlcNAc motif at the new reducing end of detected fragments. Our 1.76 Å structure of the C-terminal domain of PgaBBb reveals a central cavity within an elongated surface groove that appears ideally suited to recognize the GlcN-GlcNAc-GlcNAc motif. The structure, in conjunction with molecular modeling and site directed mutagenesis led to the identification of the dPNAG binding subsites and D474 as the probable catalytic acid. This work expands the role of PgaB within the PNAG biosynthesis machinery, defines a new glycoside hydrolase family GH153, and identifies PgaB as a possible therapeutic agent for treating PNAG-dependent biofilm infections. From plaque on teeth to infections in the lungs of cystic fibrosis patients, biofilms are a serious health concern and difficult to eradicate. One of the key building blocks involved in biofilm formation are polymeric sugar compounds that are secreted by the bacteria. Our work focuses on the biopolymer poly-β(1,6)-N-acetyl-D-glucosamine (PNAG), which is produced by numerous pathogenic organisms. Deacetylation of PNAG by the N-terminal domain of PgaB is a critical step in polymer maturation and is required for the formation of robust biofilms. Herein, we show that the C-terminal domain of PgaB is a glycoside hydrolase active on partially deacetylated PNAG, and that the enzyme disrupts PNAG-dependent biofilms and potentiates killing by antibiotics. Only deacetylated PNAG could be cleaved, suggesting that PgaB deacetylates and hydrolyses the polymer in sequential order. Analyzing the chemical structure of the cleaved dPNAG fragments revealed a distinct motif of sugar units. Structural and functional studies identify key amino acids positioned in an elongated polymer-binding groove that potentially recognize the sugar motif during cleavage. Our study provides further insight into the mechanism of periplasmic PNAG modification, and suggests PgaB could be utilized as a therapeutic agent to eliminate biofilms.
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Affiliation(s)
- Dustin J Little
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Roland Pfoh
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - François Le Mauff
- Departments of Medicine and of Microbiology and Immunology, McGill University, Montréal, QC, Canada.,Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - Natalie C Bamford
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Christina Notte
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Perrin Baker
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Manita Guragain
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC, United States of America.,Department of Microbial Infection and Immunity, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
| | - Howard Robinson
- Photon Sciences Division, Brookhaven National Laboratory, Upton, NY, United States of America
| | - Gerald B Pier
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States of America
| | - Mark Nitz
- Department of Chemistry, University of Toronto, Toronto, ON, Canada
| | - Rajendar Deora
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC, United States of America.,Department of Microbial Infection and Immunity, The Ohio State University Wexner Medical Center, Columbus, OH, United States of America
| | - Donald C Sheppard
- Departments of Medicine and of Microbiology and Immunology, McGill University, Montréal, QC, Canada.,Infectious Diseases and Immunity in Global Health Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - P Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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10
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Pfoh R, Pai EF, Saridakis V. Nicotinamide mononucleotide adenylyltransferase displays alternate binding modes for nicotinamide nucleotides. Acta Crystallogr D Biol Crystallogr 2015; 71:2032-9. [PMID: 26457427 PMCID: PMC4601368 DOI: 10.1107/s1399004715015497] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 08/18/2015] [Indexed: 11/10/2022]
Abstract
Nicotinamide mononucleotide adenylyltransferase (NMNAT) catalyzes the biosynthesis of NAD(+) and NaAD(+). The crystal structure of NMNAT from Methanobacterium thermoautotrophicum complexed with NAD(+) and SO4(2-) revealed the active-site residues involved in binding and catalysis. Site-directed mutagenesis was used to further characterize the roles played by several of these residues. Arg11 and Arg136 were implicated in binding the phosphate groups of the ATP substrate. Both of these residues were mutated to lysine individually. Arg47 does not interact with either NMN or ATP substrates directly, but was deemed to play a role in binding as it is proximal to Arg11 and Arg136. Arg47 was mutated to lysine and glutamic acid. Surprisingly, when expressed in Escherichia coli all of these NMNAT mutants trapped a molecule of NADP(+) in their active sites. This NADP(+) was bound in a conformation that was quite different from that displayed by NAD(+) in the native enzyme complex. When NADP(+) was co-crystallized with wild-type NMNAT, the same structural arrangement was observed. These studies revealed a different conformation of NADP(+) in the active site of NMNAT, indicating plasticity of the active site.
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Affiliation(s)
- Roland Pfoh
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
| | - Emil F. Pai
- Campbell Family Institute for Cancer Research, Princess Margaret Cancer Center, University Health Network, Toronto Medical Discovery Tower–MaRS Centre, 101 College Street, Toronto, ON M5G 1L7, Canada
- Departments of Biochemistry, Medical Biophysics and Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
| | - Vivian Saridakis
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
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11
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Ravulapalli R, Lugo MR, Pfoh R, Visschedyk D, Poole A, Fieldhouse RJ, Pai EF, Merrill AR. Characterization of Vis Toxin, a Novel ADP-Ribosyltransferase from Vibrio splendidus. Biochemistry 2015; 54:5920-36. [PMID: 26352925 DOI: 10.1021/acs.biochem.5b00921] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vis toxin was identified by a bioinformatics strategy as a putative virulence factor produced by Vibrio splendidus with mono-ADP-ribosyltransferase activity. Vis was purified to homogeneity as a 28 kDa single-domain enzyme and was shown to possess NAD(+)-glycohydrolase [KM(NAD(+)) = 276 ± 12 μM] activity and with an R-S-E-X-E motif; it targets arginine-related compounds [KM(agmatine) = 272 ± 18 mM]. Mass spectrometry analysis revealed that Vis labels l-arginine with ADP-ribose from the NAD(+) substrate at the amino nitrogen of the guanidinium side chain. Vis is toxic to yeast when expressed in the cytoplasm under control of the CUP1 promotor, and catalytic variants lost the ability to kill the yeast host, indicating that the toxin exerts its lethality through its enzyme activity. Several small molecule inhibitors were identified from a virtual screen, and the most potent compounds were found to inhibit the transferase activity of the enzyme with Ki values ranging from 25 to 134 μM. Inhibitor compound M6 bears the necessary attributes of a solid candidate as a lead compound for therapeutic development. Vis toxin was crystallized, and the structures of the apoenzyme (1.4 Å) and the enzyme bound with NAD(+) (1.8 Å) and with the M6 inhibitor (1.5 Å) were determined. The structures revealed that Vis represents a new subgroup within the mono-ADP-ribosyltransferase toxin family.
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Affiliation(s)
- Ravikiran Ravulapalli
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada N1G 2W1
| | - Miguel R Lugo
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada N1G 2W1
| | - Roland Pfoh
- Department of Biology, York University , Toronto, ON, Canada M3J 1P3.,Department of Biochemistry, University of Toronto , Toronto, ON, Canada M5S 1A8.,Campbell Family Institute for Cancer Research, Princess Margaret Hospital , Toronto, ON, Canada M5G 1L7
| | - Danielle Visschedyk
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada N1G 2W1
| | - Amanda Poole
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada N1G 2W1
| | - Robert J Fieldhouse
- Computational Biology Center, Memorial Sloan-Kettering Cancer Center , New York, New York 10065, United States.,Department of Systems Biology, Harvard Medical School , Boston, Massachusetts 02115, United States
| | - Emil F Pai
- Department of Biochemistry, University of Toronto , Toronto, ON, Canada M5S 1A8.,Campbell Family Institute for Cancer Research, Princess Margaret Hospital , Toronto, ON, Canada M5G 1L7.,Departments of Medical Biophysics and Molecular Genetics, University of Toronto , Toronto, ON, Canada M5S 1A8
| | - A Rod Merrill
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada N1G 2W1
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Abstract
Deubiquitinases (DUBs) play important roles and therefore are potential drug targets in various diseases including cancer and neurodegeneration. In this review, we recapitulate structure-function studies of the most studied DUBs including USP7, USP22, CYLD, UCHL1, BAP1, A20, as well as ataxin 3 and connect them to regulatory mechanisms and their growing protein interaction networks. We then describe DUBs that have been associated with endocrine carcinogenesis with a focus on prostate, ovarian, and thyroid cancer, pheochromocytoma, and adrenocortical carcinoma. The goal is enhancing our understanding of the connection between dysregulated DUBs and cancer to permit the design of therapeutics and to establish biomarkers that could be used in diagnosis and prognosis.
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Affiliation(s)
- Roland Pfoh
- Department of BiologyYork University, 4700 Keele Street, Toronto, Ontario, Canada, M3J1P3
| | - Ira Kay Lacdao
- Department of BiologyYork University, 4700 Keele Street, Toronto, Ontario, Canada, M3J1P3
| | - Vivian Saridakis
- Department of BiologyYork University, 4700 Keele Street, Toronto, Ontario, Canada, M3J1P3
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Payandeh J, Pfoh R, Pai EF. The structure and regulation of magnesium selective ion channels. Biochim Biophys Acta 2013; 1828:2778-92. [PMID: 23954807 DOI: 10.1016/j.bbamem.2013.08.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/30/2013] [Accepted: 08/02/2013] [Indexed: 10/26/2022]
Abstract
The magnesium ion (Mg(2+)) is the most abundant divalent cation within cells. In man, Mg(2+)-deficiency is associated with diseases affecting the heart, muscle, bone, immune, and nervous systems. Despite its impact on human health, little is known about the molecular mechanisms that regulate magnesium transport and storage. Complete structural information on eukaryotic Mg(2+)-transport proteins is currently lacking due to associated technical challenges. The prokaryotic MgtE and CorA magnesium transport systems have recently succumbed to structure determination by X-ray crystallography, providing first views of these ubiquitous and essential Mg(2+)-channels. MgtE and CorA are unique among known membrane protein structures, each revealing a novel protein fold containing distinct arrangements of ten transmembrane-spanning α-helices. Structural and functional analyses have established that Mg(2+)-selectivity in MgtE and CorA occurs through distinct mechanisms. Conserved acidic side-chains appear to form the selectivity filter in MgtE, whereas conserved asparagines coordinate hydrated Mg(2+)-ions within the selectivity filter of CorA. Common structural themes have also emerged whereby MgtE and CorA sense and respond to physiologically relevant, intracellular Mg(2+)-levels through dedicated regulatory domains. Within these domains, multiple primary and secondary Mg(2+)-binding sites serve to staple these ion channels into their respective closed conformations, implying that Mg(2+)-transport is well guarded and very tightly regulated. The MgtE and CorA proteins represent valuable structural templates to better understand the related eukaryotic SLC41 and Mrs2-Alr1 magnesium channels. Herein, we review the structure, function and regulation of MgtE and CorA and consider these unique proteins within the expanding universe of ion channel and transporter structural biology.
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Affiliation(s)
- Jian Payandeh
- Department of Structural Biology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
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Mernyak E, Huber J, Benedek G, Pfoh R, Rühl S, Schneider G, Wölfling J. Electrophile- and Lewis acid-induced nitrone formation and 1,3-dpolar cycloaddition reactions in the 13α- and 13β-estrone series. ARKIVOC 2010. [DOI: 10.3998/ark.5550190.0011.b10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Hoyk Z, Csákvári E, Szájli A, Kóti J, Paragi G, Gyenes A, Wölfling J, Pfoh R, Rühl S, Párducz A. Computer-aided structure analysis of an epimerized dehydroepiandrosterone derivative and its biological effect in a model of reactive gliosis. Steroids 2010; 75:265-71. [PMID: 20064537 DOI: 10.1016/j.steroids.2010.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 11/06/2009] [Accepted: 01/03/2010] [Indexed: 11/28/2022]
Abstract
The naturally occurring steroid dehydroepiandrosterone (DHEA) is reported to reduce glial fibrillary acidic protein (GFAP) overexpression in a model of reactive gliosis due to its conversion to estradiol by the enzyme aromatase. In the present study we examined the biological effect of a new epimerized derivative of DHEA, 16alpha-iodomethyl-13alpha-dehydroepiandrosterone derivative (16alpha-iodomethyl-13alpha-DHEAd, 16alpha-iodomethyl-13alpha-androst-5-en-3beta,17beta-diol), using the same model system, and compared the 3D structure of this molecule with that of DHEA and two steroidal type aromatase inhibitors, formestane and exemestane. The synthetic compound, in contrast to the reported effect of DHEA, was able to reduce GFAP overexpression only if the enzyme aromatase was inhibited. Data obtained from computational calculations fortified by X-ray crystallography revealed that contrary to the nearly planar sterane framework of DHEA, the synthetic derivative 16alpha-iodomethyl-13alpha-DHEAd has a bent sterane skeleton, resulting in a 3D structure that is similar to that of formestane or exemestane. Moreover, 16alpha-iodomethyl-13alpha-DHEAd resulted to be metabolically more stable than DHEA. The results suggest that epimerization of the sterane skeleton of DHEA inclines the plane of the D ring, leading to a significantly altered biological activity. The synthetic molecule has a DHEA-like effect on GFAP overexpression when the enzyme aromatase is inhibited and the naturally occurring DHEA is ineffective in this respect. On the other hand, based on their structural similarity it can be hypothesized that 16alpha-iodomethyl-13alpha-DHEAd applied alone might have a biological effect similar to that of formestane or exemestane.
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Affiliation(s)
- Zsófia Hoyk
- Institute of Biophysics, Biological Research Center, Szeged, Temesvári krt. 62, H-6726 Szeged, Hungary
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Pfoh R, Cuesta-Seijo JA, Sheldrick GM. Interaction of an echinomycin-DNA complex with manganese ions. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:660-4. [PMID: 19574634 PMCID: PMC2705629 DOI: 10.1107/s1744309109019654] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2009] [Accepted: 05/23/2009] [Indexed: 11/10/2022]
Abstract
The crystal structure of an echinomycin-d(ACGTACGT) duplex interacting with manganese(II) was solved by Mn-SAD using in-house data and refined to 1.1 A resolution against synchrotron data. This complex crystallizes in a different space group compared with related complexes and shows a different mode of base pairing next to the bis-intercalation site, suggesting that the energy difference between Hoogsteen and Watson-Crick pairing is rather small. The binding of manganese to N7 of guanine is only possible because of DNA unwinding induced by the echinomycin, which might help to explain the mode of action of the drug.
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Affiliation(s)
- Roland Pfoh
- Department of Structural Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Jose A. Cuesta-Seijo
- Department of Structural Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - George M. Sheldrick
- Department of Structural Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
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de Meijere A, Rauch K, Schrader B, Brackmann F, Pfoh R, Rühl S, Katoh Y, Okamoto Y, Wodrich MD, Corminboeuf C, Schreiner PR. 1,1′-Bi(trishomobarrelenyl) - Synthesis and Chiroptic Properties. European J Org Chem 2009. [DOI: 10.1002/ejoc.200801111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ding L, Pfoh R, Rühl S, Qin S, Laatsch H. T-muurolol sesquiterpenes from the marine Streptomyces sp. M491 and revision of the configuration of previously reported amorphanes. J Nat Prod 2009; 72:99-101. [PMID: 19072130 DOI: 10.1021/np8006843] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Two new sesquiterpenes, 15-hydroxy-T-muurolol (3d) and 11,15-dihydroxy-T-muurolol (3e), along with the plant cadinenes T-muurolol (3f) and 3alpha-hydroxy-T-muurolol (3g), were isolated from the marine-derived Streptomyces sp. M491. Their absolute configuration was established via NMR spectroscopy and X-ray crystallography of 3-oxo-T-muurolol (3a), which was reisolated from this strain. In addition, the absolute configuration of further sesquiterpenes previously reported from this strain was revised. These products were tested for their cytotoxicity against 37 human tumor cell lines using the MTT method. Only 3d was cytotoxic against a range of human tumor cell lines with a mean IC50 of 6.7 microg/mL.
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Affiliation(s)
- Ling Ding
- Department of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, D-37077 Göttingen, Germany
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Abstract
We report a crystal structure that shows an antibiotic that extracts a nucleobase from a DNA molecule ‘caught in the act’ after forming a covalent bond but before departing with the base. The structure of trioxacarcin A covalently bound to double-stranded d(AACCGGTT) was determined to 1.78 Å resolution by MAD phasing employing brominated oligonucleotides. The DNA–drug complex has a unique structure that combines alkylation (at the N7 position of a guanine), intercalation (on the 3′-side of the alkylated guanine), and base flip-out. An antibiotic-induced flipping-out of a single, nonterminal nucleobase from a DNA duplex was observed for the first time in a crystal structure.
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Affiliation(s)
- Roland Pfoh
- Lehrstuhl für Strukturchemie, Georg-August-Universität, Tammannstr. 4, 37077 Göttingen, Germany
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Tietze L, Schuster H, Hampel S, Rühl S, Pfoh R. Enantio- and Diastereoselective Synthesis of Duocarmycine-Based Prodrugs for a Selective Treatment of Cancer by Epoxide Opening. Chemistry 2008; 14:895-901. [DOI: 10.1002/chem.200700988] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Reaction of potassium salts of sterically demanding pyrazolates (pz = bis-3,5-tert-butylpyrazolate, pz= bis-3,5-tert-butyl-4-methylpyrazolate) with Re2O7 affords soluble eta2-pyrazolate complexes of the type [(eta2-pz)ReO3(THF)n](1: pz, n= 1 and 2: pz, n= 0). They were characterized by spectroscopic methods and by X-ray crystallography confirming the eta2-coordinate ligands. Complex 1 employing the ligand with a proton in the 4-position retains one molecule of THF, whereas the additional methyl group in 2 leads to the base-free compound 2. Compound 1 reacts with pyridine and 3,5-dimethylpyridine to form Lewis base adducts of the type [(eta2-pz)ReO3(L)](3: L = py; 4: L = 3,5-Me2py). The pronounced sensitivity towards water of these complexes is demonstrated by the reaction of 1 with one equivalent of water forming the corresponding pyrazolium perrhenate [ReO4][pzH2](5). Its solid state structure shows a hydrogen bonded dimeric assembly. Catalytic activity of 1 is established in oxygen atom transfer-reactions (OAT) from dimethylsulfoxide to triphenylphosphine, and in epoxidations of cyclooctene employing bis(trimethylsilyl) peroxide (BTSP).
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Affiliation(s)
- Nadia C Mosch-Zanetti
- Institut fur Anorganische Chemie, Georg-August-Universitat Gottingen, Tammannstrasse 4, D-37077 Gottingen, Germany.
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