1
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Kelly SD, Allas MJ, Goodridge LD, Lowary TL, Whitfield C. Structure, biosynthesis and regulation of the T1 antigen, a phase-variable surface polysaccharide conserved in many Salmonella serovars. Nat Commun 2024; 15:6504. [PMID: 39090110 PMCID: PMC11294581 DOI: 10.1038/s41467-024-50957-y] [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: 03/05/2024] [Accepted: 07/22/2024] [Indexed: 08/04/2024] Open
Abstract
The bacterial genus Salmonella includes diverse isolates with multiple variations in the structure of the main polysaccharide component (O antigen) of membrane lipopolysaccharides. In addition, some isolates produce a transient (T) antigen, such as the T1 polysaccharide identified in the 1960s in an isolate of Salmonella enterica Paratyphi B. The structure and biosynthesis of the T1 antigen have remained enigmatic. Here, we use biophysical, biochemical and genetic methods to show that the T1 antigen is a complex linear glycan containing tandem homopolymeric domains of galactofuranose and ribofuranose, linked to lipid A-core, like a typical O antigen. T1 is a phase-variable antigen, regulated by recombinational inversion of the promoter upstream of the T1 genetic locus through a mechanism not observed for other bacterial O antigens. The T1 locus is conserved across many Salmonella isolates, but is mutated or absent in most typhoidal serovars and in serovar Enteritidis.
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Affiliation(s)
- Steven D Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Mikel Jason Allas
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei, Taiwan
| | | | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada.
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei, Taiwan.
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.
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2
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Su T, Chua WZ, Liu Y, Fan J, Tan SY, Yang DW, Sham LT. Rewiring the pneumococcal capsule pathway for investigating glycosyltransferase specificity and genetic glycoengineering. SCIENCE ADVANCES 2023; 9:eadi8157. [PMID: 37672581 PMCID: PMC10482335 DOI: 10.1126/sciadv.adi8157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/03/2023] [Indexed: 09/08/2023]
Abstract
Virtually all living cells are covered with glycans. Their structures are primarily controlled by the specificities of glycosyltransferases (GTs). GTs typically adopt one of the three folds, namely, GT-A, GT-B, and GT-C. However, what defines their specificities remain poorly understood. Here, we developed a genetic glycoengineering platform by reprogramming the capsular polysaccharide pathways in Streptococcus pneumoniae to interrogate GT specificity and manipulate glycan structures. Our findings suggest that the central cleft of GT-B enzymes is important for determining acceptor specificity. The constraint of the glycoengineering platform was partially alleviated when the specificity of the precursor transporter was reduced, indicating that the transporter contributes to the overall fidelity of glycan synthesis. We also modified the pneumococcal capsule to produce several medically important mammalian glycans, as well as demonstrated the importance of regiochemistry in a glycosidic linkage on binding lung epithelial cells. Our work provided mechanistic insights into GT specificity and an approach for investigating glycan functions.
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Affiliation(s)
- Tong Su
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Wan-Zhen Chua
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Yao Liu
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Jingsong Fan
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117545, Singapore
| | - Si-Yin Tan
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Dai-wen Yang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117545, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
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3
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Controlled processivity in glycosyltransferases: A way to expand the enzymatic toolbox. Biotechnol Adv 2023; 63:108081. [PMID: 36529206 DOI: 10.1016/j.biotechadv.2022.108081] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/20/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022]
Abstract
Glycosyltransferases (GT) catalyse the biosynthesis of complex carbohydrates which are the most abundant group of molecules in nature. They are involved in several key mechanisms such as cell signalling, biofilm formation, host immune system invasion or cell structure and this in both prokaryotic and eukaryotic cells. As a result, research towards complete enzyme mechanisms is valuable to understand and elucidate specific structure-function relationships in this group of molecules. In a next step this knowledge could be used in GT protein engineering, not only for rational drug design but also for multiple biotechnological production processes, such as the biosynthesis of hyaluronan, cellooligosaccharides or chitooligosaccharides. Generation of these poly- and/or oligosaccharides is possible due to a common feature of several of these GTs: processivity. Enzymatic processivity has the ability to hold on to the growing polymer chain and some of these GTs can even control the number of glycosyl transfers. In a first part, recent advances in understanding the mechanism of various processive enzymes are discussed. To this end, an overview is given of possible engineering strategies for the purpose of new industrial and fundamental applications. In the second part of this review, we focused on specific chain length-controlling mechanisms, i.e., key residues or conserved regions, and this for both eukaryotic and prokaryotic enzymes.
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4
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Harvey DJ. ANALYSIS OF CARBOHYDRATES AND GLYCOCONJUGATES BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY: AN UPDATE FOR 2015-2016. MASS SPECTROMETRY REVIEWS 2021; 40:408-565. [PMID: 33725404 DOI: 10.1002/mas.21651] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/24/2020] [Indexed: 06/12/2023]
Abstract
This review is the ninth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2016. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented over 30 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show no sign of deminishing. © 2020 Wiley Periodicals, Inc.
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Affiliation(s)
- David J Harvey
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Roosevelt Drive, Oxford, OX3 7FZ, United Kingdom
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5
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Hu JP, Wu ZX, Xie T, Liu XY, Yan X, Sun X, Liu W, Liang L, He G, Gan Y, Gou XJ, Shi Z, Zou Q, Wan H, Shi HB, Chang S. Applications of Molecular Simulation in the Discovery of Antituberculosis Drugs: A Review. Protein Pept Lett 2019; 26:648-663. [PMID: 31218945 DOI: 10.2174/0929866526666190620145919] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/10/2019] [Accepted: 05/03/2019] [Indexed: 02/05/2023]
Abstract
After decades of efforts, tuberculosis has been well controlled in most places. The existing drugs are no longer sufficient for the treatment of drug-resistant Mycobacterium tuberculosis due to significant toxicity and selective pressure, especially for XDR-TB. In order to accelerate the development of high-efficiency, low-toxic antituberculosis drugs, it is particularly important to use Computer Aided Drug Design (CADD) for rational drug design. Here, we systematically reviewed the specific role of molecular simulation in the discovery of new antituberculosis drugs. The purpose of this review is to overview current applications of molecular simulation methods in the discovery of antituberculosis drugs. Furthermore, the unique advantages of molecular simulation was discussed in revealing the mechanism of drug resistance. The comprehensive use of different molecular simulation methods will help reveal the mechanism of drug resistance and improve the efficiency of rational drug design. With the help of molecular simulation methods such as QM/MM method, the mechanisms of biochemical reactions catalyzed by enzymes at atomic level in Mycobacterium tuberculosis has been deeply analyzed. QSAR and virtual screening both accelerate the development of highefficiency, low-toxic potential antituberculosis drugs. Improving the accuracy of existing algorithms and developing more efficient new methods for CADD will always be a hot topic in the future. It is of great value to utilize molecular dynamics simulation to investigate complex systems that cannot be studied in experiments, especially for drug resistance of Mycobacterium tuberculosis.
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Affiliation(s)
- Jian-Ping Hu
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Zhi-Xiang Wu
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Tao Xie
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Xin-Yu Liu
- Laboratory of Tumor Targeted and Immune Therapy, Clinical Research Center for Breast, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Xiao Yan
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Xin Sun
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Wei Liu
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Li Liang
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Gang He
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Ya Gan
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Xiao-Jun Gou
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Zheng Shi
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Qiang Zou
- College of Pharmacy and Biological Engineering, Sichuan Industrial Institute of Antibiotics, Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Chengdu University, Chengdu, China
| | - Hua Wan
- College of Mathematics and Informatics, South China Agricultural University, Guangzhou, China
| | - Hu-Bing Shi
- Laboratory of Tumor Targeted and Immune Therapy, Clinical Research Center for Breast, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China
| | - Shan Chang
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou, China
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6
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Calabretta PJ, Hodges HL, Kraft MB, Marando VM, Kiessling LL. Bacterial Cell Wall Modification with a Glycolipid Substrate. J Am Chem Soc 2019; 141:9262-9272. [PMID: 31081628 DOI: 10.1021/jacs.9b02290] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite the ubiquity and importance of glycans in biology, methods to probe their structures in cells are limited. Mammalian glycans can be modulated using metabolic incorporation, a process in which non-natural sugars are taken up by cells, converted to nucleotide-sugar intermediates, and incorporated into glycans via biosynthetic pathways. These studies have revealed that glycan intermediates can be shunted through multiple pathways, and this complexity can be heightened in bacteria, as they can catabolize diverse glycans. We sought to develop a strategy that probes structures recalcitrant to metabolic incorporation and that complements approaches focused on nucleotide sugars. We reasoned that lipid-linked glycans, which are intermediates directly used in glycan biosynthesis, would offer an alternative. We generated synthetic arabinofuranosyl phospholipids to test this strategy in Corynebacterium glutamicum and Mycobacterium smegmatis, organisms that serve as models of Mycobacterium tuberculosis. Using a C. glutamicum mutant that lacks arabinan, we identified synthetic glycosyl donors whose addition restores cell wall arabinan, demonstrating that non-natural glycolipids can serve as biosynthetic intermediates and function in chemical complementation. The addition of an isotopically labeled glycan substrate facilitated cell wall characterization by NMR. Structural analysis revealed that all five known arabinofuranosyl transferases could process the exogenous lipid-linked sugar donor, allowing for the full recovery of the cell envelope. The lipid-based probe could also rescue wild-type cells treated with an inhibitor of cell wall biosynthesis. Our data indicate that surrogates of natural lipid-linked glycans can intervene in the cell's traditional workflow, indicating that biosynthetic incorporation is a powerful strategy for probing glycan structure and function.
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Affiliation(s)
- Phillip J Calabretta
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | | | | | - Victoria M Marando
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Laura L Kiessling
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
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7
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Yamatsugu K. [How My Experiences in Asymmetric Catalysis and Glycobiology Led to My Current Research in Synthetic Post-translational Modifications by Chemical Catalysts]. YAKUGAKU ZASSHI 2019; 139:187-198. [PMID: 30713228 DOI: 10.1248/yakushi.18-00169-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Conducting research abroad can be an invaluable experience. I would like to share my own experiences as an example of how one's PhD course research (in the laboratory of Shibasaki Masakatsu) and research abroad (University of Wisconsin-Madison, laboratory of Laura Kiessling) can contribute to one's subsequent research. During my PhD course research in Japan, I investigated asymmetric catalysis in the efficient production of physiologically active substances. Then I moved to the U.S. and worked on the functional analysis of enzymes (biocatalysts), with a specific focus on glycosyltranspolymerase. Now I am working on the development of chemical catalysts that can introduce post-translational modifications into proteins, especially histones. Being based in catalysis, I have aimed at research that can contribute to the life sciences. In this account, I share my thought process on selecting such a career path, discuss how it affected my current research, and touch on the positive aspects as well as points for reflection when conducting research abroad.
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Affiliation(s)
- Kenzo Yamatsugu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
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8
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Ati J, Colas C, Lafite P, Sweeney RP, Zheng RB, Lowary TL, Daniellou R. The LPG1x family from Leishmania major is constituted of rare eukaryotic galactofuranosyltransferases with unprecedented catalytic properties. Sci Rep 2018; 8:17566. [PMID: 30514885 PMCID: PMC6279836 DOI: 10.1038/s41598-018-35847-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 11/09/2018] [Indexed: 12/15/2022] Open
Abstract
Galactofuranosyltransferases are poorly described enzymes despite their crucial role in the virulence and the pathogenicity of numerous microorganisms. These enzymes are considered as potential targets for therapeutic action. In addition to the only well-characterised prokaryotic GlfT2 from Mycobacterium tuberculosis, four putative genes in Leishmania major were previously described as potential galactofuranosyltransferases. In this study, we have cloned, over-expressed, purified and fully determined the kinetic parameters of these four eukaryotic enzymes, thus demonstrating their unique potency in catalysing the transfer of the galactofuranosyl moiety into acceptors. Their individual promiscuity revealed to be different, as some of them could efficiently use NDP-pyranoses as donor substrates in addition to the natural UDP-galactofuranose. Such results pave the way for the development of chemoenzymatic synthesis of furanosyl-containing glycoconjugates as well as the design of improved drugs against leishmaniasis.
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Affiliation(s)
- Jihen Ati
- Institut de Chimie Organique et Analytique, UMR CNRS 7311, Université d'Orléans, Rue de Chartres, BP6759, Orléans, Cedex 02, France
| | - Cyril Colas
- Institut de Chimie Organique et Analytique, UMR CNRS 7311, Université d'Orléans, Rue de Chartres, BP6759, Orléans, Cedex 02, France
| | - Pierre Lafite
- Institut de Chimie Organique et Analytique, UMR CNRS 7311, Université d'Orléans, Rue de Chartres, BP6759, Orléans, Cedex 02, France
| | - Ryan P Sweeney
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Ruixiang Blake Zheng
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry, The University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Richard Daniellou
- Institut de Chimie Organique et Analytique, UMR CNRS 7311, Université d'Orléans, Rue de Chartres, BP6759, Orléans, Cedex 02, France.
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9
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Janoš P, Kozmon S, Tvaroška I, Koča J. How Mycobacterium tuberculosis
Galactofuranosyl Transferase 2 (GlfT2) Generates Alternating β-(1-6) and β-(1-5) Linkages: A QM/MM Molecular Dynamics Study of the Chemical Steps. Chemistry 2018; 24:7051-7059. [DOI: 10.1002/chem.201800558] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Pavel Janoš
- Central European Institute of Technology (CEITEC); Masaryk University; Kamenice 5 625 00 Brno Czech Republic
- Faculty of Science-National Centre for Biomolecular Research; Masaryk University; Kamenice 5 625 00 Brno Czech Republic
| | - Stanislav Kozmon
- Central European Institute of Technology (CEITEC); Masaryk University; Kamenice 5 625 00 Brno Czech Republic
- Institute of Chemistry; Slovak Academy of Sciences; Dúbravská cesta 9 SK-845 38 Bratislava Slovakia
| | - Igor Tvaroška
- Central European Institute of Technology (CEITEC); Masaryk University; Kamenice 5 625 00 Brno Czech Republic
- Institute of Chemistry; Slovak Academy of Sciences; Dúbravská cesta 9 SK-845 38 Bratislava Slovakia
| | - Jaroslav Koča
- Central European Institute of Technology (CEITEC); Masaryk University; Kamenice 5 625 00 Brno Czech Republic
- Faculty of Science-National Centre for Biomolecular Research; Masaryk University; Kamenice 5 625 00 Brno Czech Republic
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10
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Legentil L, Cabezas Y, Tasseau O, Tellier C, Daligault F, Ferrières V. Regioselective Galactofuranosylation for the Synthesis of Disaccharide Patterns Found in Pathogenic Microorganisms. J Org Chem 2017. [DOI: 10.1021/acs.joc.7b00565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Laurent Legentil
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée
de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
| | - Yari Cabezas
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée
de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
| | - Olivier Tasseau
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée
de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
| | - Charles Tellier
- Université de Nantes, UMR CNRS 6286, 2 Rue de la Houssinière, 44322 Nantes Cedex 3, France
| | - Franck Daligault
- Université de Nantes, UMR CNRS 6286, 2 Rue de la Houssinière, 44322 Nantes Cedex 3, France
| | - Vincent Ferrières
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée
de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
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11
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Wesener DA, Levengood MR, Kiessling LL. Comparing Galactan Biosynthesis in Mycobacterium tuberculosis and Corynebacterium diphtheriae. J Biol Chem 2016; 292:2944-2955. [PMID: 28039359 DOI: 10.1074/jbc.m116.759340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 12/28/2016] [Indexed: 11/06/2022] Open
Abstract
The suborder Corynebacterineae encompasses species like Corynebacterium glutamicum, which has been harnessed for industrial production of amino acids, as well as Corynebacterium diphtheriae and Mycobacterium tuberculosis, which cause devastating human diseases. A distinctive component of the Corynebacterineae cell envelope is the mycolyl-arabinogalactan (mAG) complex. The mAG is composed of lipid mycolic acids, and arabinofuranose (Araf) and galactofuranose (Galf) carbohydrate residues. Elucidating microbe-specific differences in mAG composition could advance biotechnological applications and lead to new antimicrobial targets. To this end, we compare and contrast galactan biosynthesis in C. diphtheriae and M. tuberculosis In each species, the galactan is constructed from uridine 5'-diphosphate-α-d-galactofuranose (UDP-Galf), which is generated by the enzyme UDP-galactopyranose mutase (UGM or Glf). UGM and the galactan are essential in M. tuberculosis, but their importance in Corynebacterium species was not known. We show that small molecule inhibitors of UGM impede C. glutamicum growth, suggesting that the galactan is critical in corynebacteria. Previous cell wall analysis data suggest the galactan polymer is longer in mycobacterial species than corynebacterial species. To explore the source of galactan length variation, a C. diphtheriae ortholog of the M. tuberculosis carbohydrate polymerase responsible for the bulk of galactan polymerization, GlfT2, was produced, and its catalytic activity was evaluated. The C. diphtheriae GlfT2 gave rise to shorter polysaccharides than those obtained with the M. tuberculosis GlfT2. These data suggest that GlfT2 alone can influence galactan length. Our results provide tools, both small molecule and genetic, for probing and perturbing the assembly of the Corynebacterineae cell envelope.
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Affiliation(s)
| | - Matthew R Levengood
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Laura L Kiessling
- From the Department of Biochemistry and .,Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
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12
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Poulin MB, Lowary TL. Chemical Insight into the Mechanism and Specificity of GlfT2, a Bifunctional Galactofuranosyltransferase from Mycobacteria. J Org Chem 2016; 81:8123-30. [PMID: 27557056 DOI: 10.1021/acs.joc.6b01501] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mycobacteria, including the human pathogen Mycobacterium tuberculosis, produce a complex cell wall structure that is essential to survival. A key component of this structure is a glycoconjugate, the mycolyl-arabinogalactan-peptidoglycan complex, which has at its core a galactan domain composed of galactofuranose (Galf) residues linked to peptidoglycan. Because galactan biosynthesis is essential for mycobacterial viability, compounds that interfere with this process are potential therapeutic agents for treating mycobacterial diseases, including tuberculosis. Galactan biosynthesis in mycobacteria involves two glycosyltransferases, GlfT1 and GlfT2, which have been the subject of increasing interest in recent years. This Synopsis summarizes efforts to characterize the mechanism and specificity of GlfT2, which is responsible for introducing the majority of the Galf residues into mycobacterial galactan.
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Affiliation(s)
- Myles B Poulin
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta , 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta , 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
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