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Olagnon C, Monjaras Feria J, Grünwald‐Gruber C, Blaukopf M, Valvano MA, Kosma P. Synthetic Phosphodiester-Linked 4-Amino-4-deoxy-l-arabinose Derivatives Demonstrate that ArnT is an Inverting Aminoarabinosyl Transferase. Chembiochem 2019; 20:2936-2948. [PMID: 31233657 PMCID: PMC6902282 DOI: 10.1002/cbic.201900349] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Indexed: 12/22/2022]
Abstract
4-Amino-4-deoxy-l-arabinopyranose (Ara4N) residues have been linked to antibiotic resistance due to reduction of the negative charge in the lipid A and core regions of the bacterial lipopolysaccharide (LPS). To study the enzymatic transfer of Ara4N onto lipid A, which is catalysed by the ArnT transferase, we chemically synthesised a series of anomeric phosphodiester-linked lipid Ara4N derivatives containing linear aliphatic chains as well as E- and Z-configured monoterpene units. Coupling reactions were based on sugar-derived H-phosphonates, followed by oxidation and global deprotection. The enzymatic Ara4N transfer was performed in vitro with crude membranes from a deep-rough mutant from Escherichia coli as acceptor. Product formation was detected by TLC and LC-ESI-QTOF mass spectrometry. Out of seven analogues tested, only the α-neryl derivative was accepted by the Burkholderia cenocepacia ArnT protein, leading to substitution of the Kdo2 -lipid A acceptor and thus affording evidence that ArnT is an inverting glycosyl transferase that requires the Z-configured double bond next to the anomeric phosphate moiety. This approach provides an easily accessible donor substrate for biochemical studies relating to modifications of bacterial LPS that modulate antibiotic resistance and immune recognition.
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Affiliation(s)
- Charlotte Olagnon
- Department of ChemistryUniversity of Natural Resources and Life Sciences–ViennaMuthgasse 181190ViennaAustria
| | - Julia Monjaras Feria
- Wellcome-Wolfson Institute of Experimental MedicineQueen's University Belfast97 Lisburn RoadBT9 7BLBelfastUK
| | - Clemens Grünwald‐Gruber
- Department of ChemistryUniversity of Natural Resources and Life Sciences–ViennaMuthgasse 181190ViennaAustria
| | - Markus Blaukopf
- Department of ChemistryUniversity of Natural Resources and Life Sciences–ViennaMuthgasse 181190ViennaAustria
| | - Miguel A. Valvano
- Wellcome-Wolfson Institute of Experimental MedicineQueen's University Belfast97 Lisburn RoadBT9 7BLBelfastUK
| | - Paul Kosma
- Department of ChemistryUniversity of Natural Resources and Life Sciences–ViennaMuthgasse 181190ViennaAustria
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2
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Anandan A, Vrielink A. Structure and function of lipid A-modifying enzymes. Ann N Y Acad Sci 2019; 1459:19-37. [PMID: 31553069 DOI: 10.1111/nyas.14244] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/26/2019] [Accepted: 09/05/2019] [Indexed: 12/30/2022]
Abstract
Lipopolysaccharides are complex molecules found in the cell envelop of many Gram-negative bacteria. The toxic activity of these molecules has led to the terminology of endotoxins. They provide bacteria with structural integrity and protection from external environmental conditions, and they interact with host signaling receptors to induce host immune responses. Bacteria have evolved enzymes that act to modify lipopolysaccharides, particularly the lipid A region of the molecule, to enable the circumvention of host immune system responses. These modifications include changes to lipopolysaccharide by the addition of positively charged sugars, such as N-Ara4N, and phosphoethanolamine (pEtN). Other modifications include hydroxylation, acylation, and deacylation of fatty acyl chains. We review the two-component regulatory mechanisms for enzymes that carry out these modifications and provide details of the structures of four enzymes (PagP, PagL, pEtN transferases, and ArnT) that modify the lipid A portion of lipopolysaccharides. We focus largely on the three-dimensional structures of these enzymes, which provide an understanding of how their substrate binding and catalytic activities are mediated. A structure-function-based understanding of these enzymes provides a platform for the development of novel therapeutics to treat antibiotic resistance.
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Affiliation(s)
- Anandhi Anandan
- School of Molecular Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Alice Vrielink
- School of Molecular Sciences, University of Western Australia, Perth, Western Australia, Australia
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Zhang H, Srinivas S, Xu Y, Wei W, Feng Y. Genetic and Biochemical Mechanisms for Bacterial Lipid A Modifiers Associated with Polymyxin Resistance. Trends Biochem Sci 2019; 44:973-988. [PMID: 31279652 DOI: 10.1016/j.tibs.2019.06.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 06/02/2019] [Accepted: 06/05/2019] [Indexed: 01/29/2023]
Abstract
Polymyxins are a group of detergent-like antimicrobial peptides that are the ultimate line of defense against carbapenem-resistant pathogens in clinical settings. Polymyxin resistance primarily originates from structural remodeling of lipid A anchored on bacterial surfaces. We integrate genetic, structural, and biochemical aspects of three major types of lipid A modifiers that have been shown to confer intrinsic colistin resistance. Namely, we highlight ArnT, a glycosyltransferase, EptA, a phosphoethanolamine transferase, and the AlmEFG tripartite system, which is restricted to EI Tor biotype of Vibrio cholerae O1. We also discuss the growing family of mobile colistin resistance (MCR) enzymes, each of which is analogous to EptA, and which pose great challenges to global public health.
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Affiliation(s)
- Huimin Zhang
- Department of Pathogen Biology and Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Swaminath Srinivas
- Department of Pathogen Biology and Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yongchang Xu
- Department of Pathogen Biology and Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Wenhui Wei
- Department of Pathogen Biology and Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Youjun Feng
- Department of Pathogen Biology and Microbiology, and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; College of Animal Sciences, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
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4
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Mann E, Whitfield C. A widespread three-component mechanism for the periplasmic modification of bacterial glycoconjugates. CAN J CHEM 2016. [DOI: 10.1139/cjc-2015-0594] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The diverse structures of bacterial glycoconjugates are generally established during the early stages of synthesis by the activities of nucleotide sugar-dependent glycosyltransferases active in the cytoplasm. However, in some cases, further modifications of varying complexity occur after the glycoconjugate is exported to the periplasm. These processes are distinguished by the involvement of polyprenyl monosphosphoryl donors and require glycosyltransferases possessing GT-C folds. Established prototypes are found in modifications of some bacterial lipopolysaccharides, where 4-amino-4-deoxy-l-arabinose is added to lipid A and glucose side branches are used to modify O-antigens. Here we review the current understanding of these systems and describe similarities to other periplasmic glycan modifications in bacteria and the N-glycosylation pathway for assembly of eukaryotic glycoproteins.
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Affiliation(s)
- Evan Mann
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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Petrou VI, Herrera CM, Schultz KM, Clarke OB, Vendome J, Tomasek D, Banerjee S, Rajashankar KR, Belcher Dufrisne M, Kloss B, Kloppmann E, Rost B, Klug CS, Trent MS, Shapiro L, Mancia F. Structures of aminoarabinose transferase ArnT suggest a molecular basis for lipid A glycosylation. Science 2016; 351:608-12. [PMID: 26912703 DOI: 10.1126/science.aad1172] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polymyxins are antibiotics used in the last line of defense to combat multidrug-resistant infections by Gram-negative bacteria. Polymyxin resistance arises through charge modification of the bacterial outer membrane with the attachment of the cationic sugar 4-amino-4-deoxy-l-arabinose to lipid A, a reaction catalyzed by the integral membrane lipid-to-lipid glycosyltransferase 4-amino-4-deoxy-L-arabinose transferase (ArnT). Here, we report crystal structures of ArnT from Cupriavidus metallidurans, alone and in complex with the lipid carrier undecaprenyl phosphate, at 2.8 and 3.2 angstrom resolution, respectively. The structures show cavities for both lipidic substrates, which converge at the active site. A structural rearrangement occurs on undecaprenyl phosphate binding, which stabilizes the active site and likely allows lipid A binding. Functional mutagenesis experiments based on these structures suggest a mechanistic model for ArnT family enzymes.
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Affiliation(s)
- Vasileios I Petrou
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Carmen M Herrera
- Department of Infectious Diseases, University of Georgia, College of Veterinary Medicine, Athens, GA 30602, USA
| | - Kathryn M Schultz
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Oliver B Clarke
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Jérémie Vendome
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA. Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - David Tomasek
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Surajit Banerjee
- Department of Chemistry and Chemical Biology, Cornell University, Northeastern Collaborative Access Team, Advanced Photon Source, Argonne, IL 60439, USA
| | - Kanagalaghatta R Rajashankar
- Department of Chemistry and Chemical Biology, Cornell University, Northeastern Collaborative Access Team, Advanced Photon Source, Argonne, IL 60439, USA
| | - Meagan Belcher Dufrisne
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Brian Kloss
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, 89 Convent Avenue, New York, NY 10027, USA
| | - Edda Kloppmann
- Department of Informatics, Bioinformatics and Computational Biology, Technische Universität München, Boltzmannstrasse 3, 85748 Garching, Germany
| | - Burkhard Rost
- Department of Informatics, Bioinformatics and Computational Biology, Technische Universität München, Boltzmannstrasse 3, 85748 Garching, Germany. Institute for Advanced Study (TUM-IAS), Technische Universität München, Boltzmannstrasse 3, 85748 Garching, Germany
| | - Candice S Klug
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - M Stephen Trent
- Department of Infectious Diseases, University of Georgia, College of Veterinary Medicine, Athens, GA 30602, USA
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA.
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Tavares-Carreón F, Fathy Mohamed Y, Andrade A, Valvano MA. ArnT proteins that catalyze the glycosylation of lipopolysaccharide share common features with bacterial N-oligosaccharyltransferases. Glycobiology 2015; 26:286-300. [PMID: 26515403 DOI: 10.1093/glycob/cwv095] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 10/26/2015] [Indexed: 02/07/2023] Open
Abstract
ArnT is a glycosyltransferase that catalyzes the addition of 4-amino-4-deoxy-l-arabinose (l-Ara4N) to the lipid A moiety of the lipopolysaccharide. This is a critical modification enabling bacteria to resist killing by antimicrobial peptides. ArnT is an integral inner membrane protein consisting of 13 predicted transmembrane helices and a large periplasmic C-terminal domain. We report here the identification of a functional motif with a canonical consensus sequence DEXRYAX(5)MX(3)GXWX(9)YFEKPX(4)W spanning the first periplasmic loop, which is highly conserved in all ArnT proteins examined. Site-directed mutagenesis demonstrated the contribution of this motif in ArnT function, suggesting that these proteins have a common mechanism. We also demonstrate that the Burkholderia cenocepacia and Salmonella enterica serovar Typhimurium ArnT C-terminal domain is required for polymyxin B resistance in vivo. Deletion of the C-terminal domain in B. cenocepacia ArnT resulted in a protein with significantly reduced in vitro binding to a lipid A fluorescent substrate and unable to catalyze lipid A modification with l-Ara4N. An in silico predicted structural model of ArnT strongly resembled the tertiary structure of Campylobacter lari PglB, a bacterial oligosaccharyltransferase involved in protein N-glycosylation. Therefore, distantly related oligosaccharyltransferases from ArnT and PglB families operating on lipid and polypeptide substrates, respectively, share unexpected structural similarity that could not be predicted from direct amino acid sequence comparisons. We propose that lipid A and protein glycosylation enzymes share a conserved catalytic mechanism despite their evolutionary divergence.
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Affiliation(s)
- Faviola Tavares-Carreón
- Department of Microbiology and Immunology, University of Western Ontario, London, ON, Canada N6A 5C1 Instituto de Biotecnología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León. Nuevo León, Mexico
| | - Yasmine Fathy Mohamed
- Centre for Infection and Immunity, Queen's University Belfast, Belfast BT9 5GZ, UK Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Angel Andrade
- Department of Microbiology and Immunology, University of Western Ontario, London, ON, Canada N6A 5C1 Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico
| | - Miguel A Valvano
- Department of Microbiology and Immunology, University of Western Ontario, London, ON, Canada N6A 5C1 Centre for Infection and Immunity, Queen's University Belfast, Belfast BT9 5GZ, UK
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Tavares-Carreón F, Patel KB, Valvano MA. Burkholderia cenocepacia and Salmonella enterica ArnT proteins that transfer 4-amino-4-deoxy-l-arabinose to lipopolysaccharide share membrane topology and functional amino acids. Sci Rep 2015; 5:10773. [PMID: 26030265 PMCID: PMC5377068 DOI: 10.1038/srep10773] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/01/2015] [Indexed: 12/27/2022] Open
Abstract
We recently demonstrated that incorporation of 4-amino-4-deoxy-l-arabinose (l-Ara4N) to the lipid A moiety of lipopolysaccharide (LPS) is required for transport of LPS to the outer membrane and viability of the Gram-negative bacterium Burkholderia cenocepacia. ArnT is a membrane protein catalyzing the transfer of l-Ara4N to the LPS molecule at the periplasmic face of the inner membrane, but its topology and mechanism of action are not well characterized. Here, we elucidate the topology of ArnT and identify key amino acids that likely contribute to its enzymatic function. PEGylation assays using a cysteineless version of ArnT support a model of 13 transmembrane helices and a large C-terminal region exposed to the periplasm. The same topological configuration is proposed for the Salmonella enterica serovar Typhimurium ArnT. Four highly conserved periplasmic residues in B. cenocepacia ArnT, tyrosine-43, lysine-69, arginine-254 and glutamic acid-493, were required for activity. Tyrosine-43 and lysine-69 span two highly conserved motifs, 42RYA44 and 66YFEKP70, that are found in ArnT homologues from other species. The same residues in S. enterica ArnT are also needed for function. We propose these aromatic and charged amino acids participate in either undecaprenyl phosphate-l-Ara4N substrate recognition or transfer of l-Ara4N to the LPS.
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Affiliation(s)
- Faviola Tavares-Carreón
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Kinnari B Patel
- Centre for Infection and Immunity, Queen's University Belfast, Belfast, BT9 7AE, United Kingdom
| | - Miguel A Valvano
- 1] Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada [2] Centre for Infection and Immunity, Queen's University Belfast, Belfast, BT9 7AE, United Kingdom
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