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Putnik R, Zhou J, Irnov I, Garner E, Liu M, Bersch KL, Jacobs-Wagner C, Grimes CL. Synthesis of a Borrelia burgdorferi-Derived Muropeptide Standard Fragment Library. Molecules 2024; 29:3297. [PMID: 39064876 PMCID: PMC11279244 DOI: 10.3390/molecules29143297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 07/01/2024] [Accepted: 07/05/2024] [Indexed: 07/28/2024] Open
Abstract
The interplay between the human innate immune system and bacterial cell wall components is pivotal in understanding diseases such as Crohn's disease and Lyme arthritis. Lyme disease, caused by Borrelia burgdorferi, is the most prevalent tick-borne illness in the United States, with a substantial number of cases reported annually. While antibiotic treatments are generally effective, approximately 10% of Lyme disease cases develop persistent arthritis, suggesting a dysregulated host immune response. We have previously identified a link between the immunogenic B. burgdorferi peptidoglycan (PG) and Lyme arthritis and showed that this pathogen sheds significant amounts of PG fragments during growth. Here, we synthesize these PG fragments, including ornithine-containing monosaccharides and disaccharides, to mimic the unique composition of Borrelia cell walls, using reproducible and rigorous synthetic methods. This synthetic approach allows for the modular preparation of PG derivatives, providing a diverse library of well-defined fragments. These fragments will serve as valuable tools for investigating the role of PG-mediated innate immune response in Lyme disease and aid in the development of improved diagnostic methods and treatment strategies.
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Affiliation(s)
- Rachel Putnik
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Junhui Zhou
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Irnov Irnov
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Elise Garner
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Min Liu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Klare L. Bersch
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Christine Jacobs-Wagner
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Sarafan Chemistry, Engineering, and Medicine for Human Health Institute, Stanford University, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Catherine Leimkuhler Grimes
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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2
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Lee SH, Kim JM, López-Álvarez M, Wang C, Sorlin AM, Bobba KN, Pichardo-González PA, Blecha J, Seo Y, Flavell RR, Engel J, Ohliger MA, Wilson DM. Imaging the Bacterial Cell Wall Using N-Acetyl Muramic Acid-Derived Positron Emission Tomography Radiotracers. ACS Sens 2023; 8:4554-4565. [PMID: 37992233 PMCID: PMC10749472 DOI: 10.1021/acssensors.3c01477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/10/2023] [Accepted: 11/07/2023] [Indexed: 11/24/2023]
Abstract
Imaging infections in patients is challenging using conventional methods, motivating the development of positron emission tomography (PET) radiotracers targeting bacteria-specific metabolic pathways. Numerous techniques have focused on the bacterial cell wall, although peptidoglycan-targeted PET tracers have been generally limited to the short-lived carbon-11 radioisotope (t1/2 = 20.4 min). In this article, we developed and tested new tools for infection imaging using an amino sugar component of peptidoglycan, namely, derivatives of N-acetyl muramic acid (NAM) labeled with the longer-lived fluorine-18 (t1/2 = 109.6 min) radioisotope. Muramic acid was reacted directly with 4-nitrophenyl 2-[18F]fluoropropionate ([18F]NFP) to afford the enantiomeric NAM derivatives (S)-[18F]FMA and (R)-[18F]FMA. Both diastereomers were easily isolated and showed robust accumulation by human pathogens in vitro and in vivo, including Staphylococcus aureus. These results form the basis for future clinical studies using fluorine-18-labeled NAM-derived PET radiotracers.
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Affiliation(s)
- Sang Hee Lee
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Jung Min Kim
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Marina López-Álvarez
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Chao Wang
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Alexandre M. Sorlin
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Kondapa Naidu Bobba
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Priamo A. Pichardo-González
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Joseph Blecha
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Youngho Seo
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Robert R. Flavell
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
- UCSF
Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California 94158, United States
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Joanne Engel
- Department
of Medicine, University of California, San
Francisco, San Francisco, California 94158, United States
- Department
of Microbiology and Immunology, University
of California, San Francisco, San
Francisco, California 94158, United States
| | - Michael A. Ohliger
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
- Department
of Radiology, Zuckerberg San Francisco General
Hospital, San Francisco, California 94110, United States
| | - David M. Wilson
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San
Francisco, California 94158, United States
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3
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El-Araby AM, Jiménez-Faraco E, Feltzer R, Martin-Garcia JM, Karri BR, Ramachandran B, Kim C, Fisher JF, Hermoso JA, Mobashery S. Catalytic process of anhydro-N-acetylmuramic acid kinase from Pseudomonas aeruginosa. J Biol Chem 2023; 299:105198. [PMID: 37660917 PMCID: PMC10570956 DOI: 10.1016/j.jbc.2023.105198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 08/24/2023] [Accepted: 08/30/2023] [Indexed: 09/05/2023] Open
Abstract
The bacterial cell envelope is the structure with which the bacterium engages with, and is protected from, its environment. Within this envelop is a conserved peptidoglycan polymer which confers shape and strength to the cell envelop. The enzymatic processes that build, remodel, and recycle the chemical components of this cross-linked polymer are preeminent targets of antibiotics and exploratory targets for emerging antibiotic structures. We report a comprehensive kinetic and structural analysis for one such enzyme, the Pseudomonas aeruginosa anhydro-N-acetylmuramic acid (anhNAM) kinase (AnmK). AnmK is an enzyme in the peptidoglycan-recycling pathway of this pathogen. It catalyzes the pairing of hydrolytic ring opening of anhNAM with concomitant ATP-dependent phosphoryl transfer. AnmK follows a random-sequential kinetic mechanism with respect to its anhNAM and ATP substrates. Crystallographic analyses of four distinct structures (apo AnmK, AnmK:AMPPNP, AnmK:AMPPNP:anhNAM, and AnmK:ATP:anhNAM) demonstrate that both substrates enter the active site independently in an ungated conformation of the substrate subsites, with protein loops acting as gates for anhNAM binding. Catalysis occurs within a closed conformational state for the enzyme. We observe this state crystallographically using ATP-mimetic molecules. A remarkable X-ray structure for dimeric AnmK sheds light on the precatalytic and postcatalytic ternary complexes. Computational simulations in conjunction with the high-resolution X-ray structures reveal the full catalytic cycle. We further report that a P. aeruginosa strain with disrupted anmK gene is more susceptible to the β-lactam imipenem compared to the WT strain. These observations position AnmK for understanding the nexus among peptidoglycan recycling, susceptibility to antibiotics, and bacterial virulence.
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Affiliation(s)
- Amr M El-Araby
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Eva Jiménez-Faraco
- Department of Crystallography and Structural Biology, Instituto de Química-Física "Blas Cabrera", Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Rhona Feltzer
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Jose M Martin-Garcia
- Department of Crystallography and Structural Biology, Instituto de Química-Física "Blas Cabrera", Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Bhaskara Rao Karri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Balajee Ramachandran
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Choon Kim
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Jed F Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Juan A Hermoso
- Department of Crystallography and Structural Biology, Instituto de Química-Física "Blas Cabrera", Consejo Superior de Investigaciones Científicas, Madrid, Spain.
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA.
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Guzman J, Raval D, Hauck D, Titz A, Poehlein A, Degenkolb T, Daniel R, Vilcinskas A. The resuscitation-promoting factor (Rpf) from Micrococcus luteus and its putative reaction product 1,6-anhydro-MurNAc increase culturability of environmental bacteria. Access Microbiol 2023; 5:000647.v4. [PMID: 37841103 PMCID: PMC10569661 DOI: 10.1099/acmi.0.000647.v4] [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: 06/13/2023] [Accepted: 09/09/2023] [Indexed: 10/17/2023] Open
Abstract
Dormant bacterial cells do not divide and are not immediately culturable, but they persist in a state of low metabolic activity, a physiological state having clinical relevance, for instance in latent tuberculosis. Resuscitation-promoting factors (Rpfs) are proteins that act as signalling molecules mediating growth and replication. In this study we aimed to test the effect of Rpfs from Micrococcus luteus on the number and diversity of cultured bacteria using insect and soil samples, and to examine if the increase in culturability could be reproduced with the putative reaction product of Rpf, 1,6-anhydro-N-acetylmuramic acid (1,6-anhydro-MurNAc). The rpf gene from Micrococcus luteus was amplified and cloned into a pET21b expression vector and the protein was expressed in Escherichia coli BL21(DE3) cells and purified by affinity chromatography using a hexa-histidine tag. 1,6-Anhydro-MurNAc was prepared using reported chemical synthesis methods. Recombinant Rpf protein or 1,6-anhydro-MurNAc were added to R2A cultivation media, and their effect on the culturability of bacteria from eight environmental samples including four cockroach guts and four soils was examined. Colony-forming units, 16S rRNA gene copies and Illumina amplicon sequencing of the 16S rRNA gene were measured for all eight samples subjected to three different treatments: Rpf, 1,6-anhydro-MurNAc or blank control. Both Rpf and 1,6-anhydro-MurNAc increased the number of colony-forming units and of 16S rRNA gene copies across the samples although the protein was more effective. The Rpf and 1,6-anhydro-MurNAc promoted the cultivation of a diverse set of bacteria and in particular certain clades of the phyla Actinomycetota and Bacillota . This study opens the path for improved cultivation strategies aiming to isolate and study yet undescribed living bacterial organisms.
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Affiliation(s)
- Juan Guzman
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
- Institute for Insect Biotechnology, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Dipansi Raval
- Institute for Insect Biotechnology, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Dirk Hauck
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
- German Center for Infection Research, site Hannover-Braunschweig, Saarbrücken, Germany
- Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Alexander Titz
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
- German Center for Infection Research, site Hannover-Braunschweig, Saarbrücken, Germany
- Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Anja Poehlein
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Thomas Degenkolb
- Institute for Insect Biotechnology, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Rolf Daniel
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Andreas Vilcinskas
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
- Institute for Insect Biotechnology, Justus-Liebig-University of Giessen, Giessen, Germany
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Tao X, Morgan JS, Liu J, Kempher ML, Xu T, Zhou J. Target integration of an exogenous β-glucosidase enhances cellulose degradation and ethanol production in Clostridium cellulolyticum. BIORESOURCE TECHNOLOGY 2023; 376:128849. [PMID: 36898565 DOI: 10.1016/j.biortech.2023.128849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/03/2023] [Accepted: 03/05/2023] [Indexed: 06/18/2023]
Abstract
The bacteria Clostridium cellulolyticum is a promising candidate for consolidated bioprocessing (CBP). However, genetic engineering is necessary to improve this organism's cellulose degradation and bioconversion efficiencies to meet standard industrial requirements. In this study, CRISPR-Cas9n was used to integrate an efficient β-glucosidase into the genome of C. cellulolyticum, disrupting lactate dehydrogenase (ldh) expression and reducing lactate production. The engineered strain showed a 7.4-fold increase in β-glucosidase activity, a 70% decrease in ldh expression, a 12% increase in cellulose degradation, and a 32% increase in ethanol production compared to wild type. Additionally, ldh was identified as a potential site for heterologous expression. These results demonstrate that simultaneous β-glucosidase integration and lactate dehydrogenase disruption is an effective strategy for increasing cellulose to ethanol bioconversion rates in C. cellulolyticum.
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Affiliation(s)
- Xuanyu Tao
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Josiah S Morgan
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Jiantao Liu
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Megan L Kempher
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Tao Xu
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA; Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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Mayer VMT, Tomek MB, Figl R, Borisova M, Hottmann I, Blaukopf M, Altmann F, Mayer C, Schäffer C. Utilization of different MurNAc sources by the oral pathogen Tannerella forsythia and role of the inner membrane transporter AmpG. BMC Microbiol 2020; 20:352. [PMID: 33203363 PMCID: PMC7670621 DOI: 10.1186/s12866-020-02006-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 10/12/2020] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The Gram-negative oral pathogen Tannerella forsythia strictly depends on the external supply of the essential bacterial cell wall sugar N-acetylmuramic acid (MurNAc) for survival because of the lack of the common MurNAc biosynthesis enzymes MurA/MurB. The bacterium thrives in a polymicrobial biofilm consortium and, thus, it is plausible that it procures MurNAc from MurNAc-containing peptidoglycan (PGN) fragments (muropeptides) released from cohabiting bacteria during natural PGN turnover or cell death. There is indirect evidence that in T. forsythia, an AmpG-like permease (Tanf_08365) is involved in cytoplasmic muropeptide uptake. In E. coli, AmpG is specific for the import of N-acetylglucosamine (GlcNAc)-anhydroMurNAc(-peptides) which are common PGN turnover products, with the disaccharide portion as a minimal requirement. Currently, it is unclear which natural, complex MurNAc sources T. forsythia can utilize and which role AmpG plays therein. RESULTS We performed a screen of various putative MurNAc sources for T. forsythia mimicking the situation in the natural habitat and compared bacterial growth and cell morphology of the wild-type and a mutant lacking AmpG (T. forsythia ΔampG). We showed that supernatants of the oral biofilm bacteria Porphyromonas gingivalis and Fusobacterium nucleatum, and of E. coli ΔampG, as well as isolated PGN and defined PGN fragments obtained after enzymatic digestion, namely GlcNAc-anhydroMurNAc(-peptides) and GlcNAc-MurNAc(-peptides), could sustain growth of T. forsythia wild-type, while T. forsythia ΔampG suffered from growth inhibition. In supernatants of T. forsythia ΔampG, the presence of GlcNAc-anhMurNAc and, unexpectedly, also GlcNAc-MurNAc was revealed by tandem mass spectrometry analysis, indicating that both disaccharides are substrates of AmpG. The importance of AmpG in the utilization of PGN fragments as MurNAc source was substantiated by a significant ampG upregulation in T. forsythia cells cultivated with PGN, as determined by quantitative real-time PCR. Further, our results indicate that PGN-degrading amidase, lytic transglycosylase and muramidase activities in a T. forsythia cell extract are involved in PGN scavenging. CONCLUSION T. forsythia metabolizes intact PGN as well as muropeptides released from various bacteria and the bacterium's inner membrane transporter AmpG is essential for growth on these MurNAc sources, and, contrary to the situation in E. coli, imports both, GlcNAc-anhMurNAc and GlcNAc-MurNAc fragments.
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Affiliation(s)
- Valentina M T Mayer
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Vienna, Austria
| | - Markus B Tomek
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Vienna, Austria
| | - Rudolf Figl
- Department of Chemistry, Institute of Biochemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Marina Borisova
- Department of Biology, Eberhard Karls Universität Tübingen, Microbiology/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Tübingen, Germany
| | - Isabel Hottmann
- Department of Biology, Eberhard Karls Universität Tübingen, Microbiology/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Tübingen, Germany
| | - Markus Blaukopf
- Department of Chemistry, Institute of Organic Chemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Friedrich Altmann
- Department of Chemistry, Institute of Biochemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Christoph Mayer
- Department of Biology, Eberhard Karls Universität Tübingen, Microbiology/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Tübingen, Germany.
| | - Christina Schäffer
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Vienna, Austria.
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Asressu KH, Wang CC. SnCl 4-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives. Beilstein J Org Chem 2019; 15:2990-2999. [PMID: 31949543 PMCID: PMC6948141 DOI: 10.3762/bjoc.15.295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/13/2019] [Indexed: 12/17/2022] Open
Abstract
Sialic acid-containing glycans are found in different sialic acid forms and a variety of glycosidic linkages in biologically active glycoconjugates. Hence, the preparation of suitably protected sialyl building blocks requires high attention in order to access glycans in a pure form. In line with this, various C-5-substituted 2,7-anhydrosialic acid derivatives bearing both electron-donating and -withdrawing protecting groups were synthesized and subjected to different Lewis acid-catalyzed solvent-free ring-opening reactions at room temperature in the presence of acetic anhydride. Among the various Lewis acids tested, the desired acetolysis products were obtained in moderate yields under tin(IV) chloride catalysis. Our methodology could be extended to regioselective protecting group installations and manipulations towards a number of thiosialoside and halide donors.
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Affiliation(s)
- Kesatebrhan Haile Asressu
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
- Taiwan International Graduate Program (TIGP), Sustainable Chemical Science and Technology (SCST), Academia Sinica, Taipei 115, Taiwan
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan
| | - Cheng-Chung Wang
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
- Taiwan International Graduate Program (TIGP), Sustainable Chemical Science and Technology (SCST), Academia Sinica, Taipei 115, Taiwan
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8
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Hottmann I, Mayer VMT, Tomek MB, Friedrich V, Calvert MB, Titz A, Schäffer C, Mayer C. N-Acetylmuramic Acid (MurNAc) Auxotrophy of the Oral Pathogen Tannerella forsythia: Characterization of a MurNAc Kinase and Analysis of Its Role in Cell Wall Metabolism. Front Microbiol 2018; 9:19. [PMID: 29434575 PMCID: PMC5790795 DOI: 10.3389/fmicb.2018.00019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/05/2018] [Indexed: 01/15/2023] Open
Abstract
Tannerella forsythia is an anaerobic, Gram-negative oral pathogen that thrives in multispecies gingival biofilms associated with periodontitis. The bacterium is auxotrophic for the commonly essential bacterial cell wall sugar N-acetylmuramic acid (MurNAc) and, thus, strictly depends on an exogenous supply of MurNAc for growth and maintenance of cell morphology. A MurNAc transporter (Tf_MurT; Tanf_08375) and an ortholog of the Escherichia coli etherase MurQ (Tf_MurQ; Tanf_08385) converting MurNAc-6-phosphate to GlcNAc-6-phosphate were recently described for T. forsythia. In between the respective genes on the T. forsythia genome, a putative kinase gene is located. In this study, the putative kinase (Tf_MurK; Tanf_08380) was produced as a recombinant protein and biochemically characterized. Kinetic studies revealed Tf_MurK to be a 6-kinase with stringent substrate specificity for MurNAc exhibiting a 6 × 104-fold higher catalytic efficiency (kcat/Km ) for MurNAc than for N-acetylglucosamine (GlcNAc) with kcat values of 10.5 s-1 and 0.1 s-1 and Km values of 200 μM and 116 mM, respectively. The enzyme kinetic data suggest that Tf_MurK is subject to substrate inhibition (Ki[S] = 4.2 mM). To assess the role of Tf_MurK in the cell wall metabolism of T. forsythia, a kinase deletion mutant (ΔTf_murK::erm) was constructed. This mutant accumulated MurNAc intracellularly in the exponential phase, indicating the capability to take up MurNAc, but inability to catabolize MurNAc. In the stationary phase, the MurNAc level was reduced in the mutant, while the level of the peptidoglycan precursor UDP-MurNAc-pentapeptide was highly elevated. Further, according to scanning electron microscopy evidence, the ΔTf_murK::erm mutant was more tolerant toward low MurNAc concentration in the medium (below 0.5 μg/ml) before transition from healthy, rod-shaped to fusiform cells occurred, while the parent strain required > 1 μg/ml MurNAc for optimal growth. These data reveal that T. forsythia readily catabolizes exogenous MurNAc but simultaneously channels a proportion of the sugar into peptidoglycan biosynthesis. Deletion of Tf_murK blocks MurNAc catabolism and allows the direction of MurNAc solely to peptidoglycan biosynthesis, resulting in a growth advantage in MurNAc-depleted medium. This work increases our understanding of the T. forsythia cell wall metabolism and may pave new routes for lead finding in the treatment of periodontitis.
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Affiliation(s)
- Isabel Hottmann
- Microbiology and Biotechnology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Department of Biology, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Valentina M. T. Mayer
- NanoGlycobiology Unit, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Vienna, Austria
| | - Markus B. Tomek
- NanoGlycobiology Unit, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Vienna, Austria
| | - Valentin Friedrich
- NanoGlycobiology Unit, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Vienna, Austria
| | - Matthew B. Calvert
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung, Partner Site Hannover-Braunschweig, Brunswick, Germany
- Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Alexander Titz
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung, Partner Site Hannover-Braunschweig, Brunswick, Germany
- Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Christina Schäffer
- NanoGlycobiology Unit, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Vienna, Austria
| | - Christoph Mayer
- Microbiology and Biotechnology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Department of Biology, Eberhard Karls Universität Tübingen, Tübingen, Germany
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