1
|
Villalta A, Schmitt A, Estrozi LF, Quemin ERJ, Alempic JM, Lartigue A, Pražák V, Belmudes L, Vasishtan D, Colmant AMG, Honoré FA, Couté Y, Grünewald K, Abergel C. The giant mimivirus 1.2 Mb genome is elegantly organized into a 30 nm diameter helical protein shield. eLife 2022; 11:77607. [PMID: 35900198 PMCID: PMC9512402 DOI: 10.7554/elife.77607] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [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: 02/04/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Mimivirus is the prototype of the Mimiviridae family of giant dsDNA viruses. Little is known about the organization of the 1.2 Mb genome inside the membrane-limited nucleoid filling the ~0.5 µm icosahedral capsids. Cryo-electron microscopy, cryo-electron tomography, and proteomics revealed that it is encased into a ~30-nm diameter helical protein shell surprisingly composed of two GMC-type oxidoreductases, which also form the glycosylated fibrils decorating the capsid. The genome is arranged in 5- or 6-start left-handed super-helices, with each DNA-strand lining the central channel. This luminal channel of the nucleoprotein fiber is wide enough to accommodate oxidative stress proteins and RNA polymerase subunits identified by proteomics. Such elegant supramolecular organization would represent a remarkable evolutionary strategy for packaging and protecting the genome, in a state ready for immediate transcription upon unwinding in the host cytoplasm. The parsimonious use of the same protein in two unrelated substructures of the virion is unexpected for a giant virus with thousand genes at its disposal.
Collapse
Affiliation(s)
| | - Alain Schmitt
- Aix-Marseille University, CNRS-AMU UMR7256, Marseille, France
| | | | | | | | - Audrey Lartigue
- Aix-Marseille University, CNRS-AMU UMR7256, Marseille, France
| | - Vojtěch Pražák
- Centre for Structural Systems Biology, University of Hamburg, Hamburg, Germany
| | - Lucid Belmudes
- Institut de Biosciences et Biotechnologies de Grenoble, Université Grenoble Alpes, Grenoble, France
| | - Daven Vasishtan
- Centre for Structural Systems Biology, University of Hamburg, Hamburg, Germany
| | | | - Flora A Honoré
- Aix-Marseille University, CNRS-AMU UMR7256, Marseille, France
| | - Yohann Couté
- Institut de Biosciences et Biotechnologies de Grenoble, Université Grenoble Alpes, Grenoble, France
| | - Kay Grünewald
- Centre for Structural Systems Biology, University of Hamburg, Hamburg, Germany
| | - Chantal Abergel
- Aix-Marseille University, CNRS-AMU UMR7256, Marseille, France
| |
Collapse
|
2
|
Speciale I, Notaro A, Abergel C, Lanzetta R, Lowary TL, Molinaro A, Tonetti M, Van Etten JL, De Castro C. The Astounding World of Glycans from Giant Viruses. Chem Rev 2022; 122:15717-15766. [PMID: 35820164 PMCID: PMC9614988 DOI: 10.1021/acs.chemrev.2c00118] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Viruses are a heterogeneous ensemble of entities, all
sharing the
need for a suitable host to replicate. They are extremely diverse,
varying in morphology, size, nature, and complexity of their genomic
content. Typically, viruses use host-encoded glycosyltransferases
and glycosidases to add and remove sugar residues from their glycoproteins.
Thus, the structure of the glycans on the viral proteins have, to
date, typically been considered to mimick those of the host. However,
the more recently discovered large and giant viruses differ from this
paradigm. At least some of these viruses code for an (almost) autonomous
glycosylation pathway. These viral genes include those that encode
the production of activated sugars, glycosyltransferases, and other
enzymes able to manipulate sugars at various levels. This review focuses
on large and giant viruses that produce carbohydrate-processing enzymes.
A brief description of those harboring these features at the genomic
level will be discussed, followed by the achievements reached with
regard to the elucidation of the glycan structures, the activity of
the proteins able to manipulate sugars, and the organic synthesis
of some of these virus-encoded glycans. During this progression, we
will also comment on many of the challenging questions on this subject
that remain to be addressed.
Collapse
Affiliation(s)
- Immacolata Speciale
- Department of Agricultural Sciences, University of Napoli, Via Università 100, 80055 Portici, Italy
| | - Anna Notaro
- Department of Agricultural Sciences, University of Napoli, Via Università 100, 80055 Portici, Italy.,Centre National de la Recherche Scientifique, Information Génomique & Structurale, Aix-Marseille University, Unité Mixte de Recherche 7256, IMM, IM2B, 13288 Marseille, Cedex 9, France
| | - Chantal Abergel
- Centre National de la Recherche Scientifique, Information Génomique & Structurale, Aix-Marseille University, Unité Mixte de Recherche 7256, IMM, IM2B, 13288 Marseille, Cedex 9, France
| | - Rosa Lanzetta
- Department of Chemical Sciences, University of Napoli, Via Cintia 4, 80126 Napoli, Italy
| | - Todd L Lowary
- Institute of Biological Chemistry, Academia Sinica, Academia Road, Section 2, Nangang 11529, Taipei, Taiwan
| | - Antonio Molinaro
- Department of Chemical Sciences, University of Napoli, Via Cintia 4, 80126 Napoli, Italy
| | - Michela Tonetti
- Department of Experimental Medicine and Center of Excellence for Biomedical Research, University of Genova, 16132 Genova, Italy
| | - James L Van Etten
- Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska 68583-0900, United States.,Department of Plant Pathology, University of Nebraska, Lincoln, Nebraska 68583-0722, United States
| | - Cristina De Castro
- Department of Agricultural Sciences, University of Napoli, Via Università 100, 80055 Portici, Italy
| |
Collapse
|
3
|
Notaro A, Couté Y, Belmudes L, Laugeri ME, Salis A, Damonte G, Molinaro A, Tonetti MG, Abergel C, De Castro C. Expanding the Occurrence of Polysaccharides to the Viral World: The Case of Mimivirus. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106671] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Anna Notaro
- Department of Chemical Sciences University of Naples Federico II Via Cinthia 21 80126 Naples Italy
- Information Génomique & Structurale Unité Mixte de Recherche 7256 Aix-Marseille University Centre National de la Recherche Scientifique, IMM, IM2B 13288 Marseille Cedex 9 France
| | - Yohann Couté
- INSERM, CEA, UMR BioSanté U1292 Univ. Grenoble Alpes CNRS, CEA, FR2048 38000 Grenoble France
| | - Lucid Belmudes
- INSERM, CEA, UMR BioSanté U1292 Univ. Grenoble Alpes CNRS, CEA, FR2048 38000 Grenoble France
| | - Maria Elena Laugeri
- Department of Experimental Medicine and Center of Excellence for Biomedical Research University of Genova Genova Italy
| | - Annalisa Salis
- Department of Experimental Medicine and Center of Excellence for Biomedical Research University of Genova Genova Italy
| | - Gianluca Damonte
- Department of Experimental Medicine and Center of Excellence for Biomedical Research University of Genova Genova Italy
| | - Antonio Molinaro
- Department of Chemical Sciences University of Naples Federico II Via Cinthia 21 80126 Naples Italy
| | - Michela G. Tonetti
- Department of Experimental Medicine and Center of Excellence for Biomedical Research University of Genova Genova Italy
| | - Chantal Abergel
- Information Génomique & Structurale Unité Mixte de Recherche 7256 Aix-Marseille University Centre National de la Recherche Scientifique, IMM, IM2B 13288 Marseille Cedex 9 France
| | - Cristina De Castro
- Department of Agricultural Sciences University of Naples Federico II Via Università, 100 80055 Portici (NA) Italy
| |
Collapse
|
4
|
Notaro A, Couté Y, Belmudes L, Laugeri ME, Salis A, Damonte G, Molinaro A, Tonetti MG, Abergel C, De Castro C. Expanding the Occurrence of Polysaccharides to the Viral World: The Case of Mimivirus. Angew Chem Int Ed Engl 2021; 60:19897-19904. [PMID: 34241943 PMCID: PMC8456856 DOI: 10.1002/anie.202106671] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 05/18/2021] [Indexed: 11/05/2022]
Abstract
The general perception of viruses is that they are small in terms of size and genome, and that they hijack the host machinery to glycosylate their capsid. Giant viruses subvert all these concepts: their particles are not small, and their genome is more complex than that of some bacteria. Regarding glycosylation, this concept has been already challenged by the finding that Chloroviruses have an autonomous glycosylation machinery that produces oligosaccharides similar in size to those of small viruses (6-12 units), albeit different in structure compared to the viral counterparts. We report herein that Mimivirus possesses a glycocalyx made of two different polysaccharides, now challenging the concept that all viruses coat their capsids with oligosaccharides of discrete size. This discovery contradicts the paradigm that such macromolecules are absent in viruses, blurring the boundaries between giant viruses and the cellular world and opening new avenues in the field of viral glycobiology.
Collapse
Affiliation(s)
- Anna Notaro
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 21, 80126, Naples, Italy.,Information Génomique & Structurale, Unité Mixte de Recherche 7256, Aix-Marseille University, Centre National de la Recherche Scientifique, IMM, IM2B, 13288, Marseille Cedex 9, France
| | - Yohann Couté
- INSERM, CEA, UMR BioSanté U1292, Univ. Grenoble Alpes, CNRS, CEA, FR2048, 38000, Grenoble, France
| | - Lucid Belmudes
- INSERM, CEA, UMR BioSanté U1292, Univ. Grenoble Alpes, CNRS, CEA, FR2048, 38000, Grenoble, France
| | - Maria Elena Laugeri
- Department of Experimental Medicine and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
| | - Annalisa Salis
- Department of Experimental Medicine and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
| | - Gianluca Damonte
- Department of Experimental Medicine and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
| | - Antonio Molinaro
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 21, 80126, Naples, Italy
| | - Michela G Tonetti
- Department of Experimental Medicine and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
| | - Chantal Abergel
- Information Génomique & Structurale, Unité Mixte de Recherche 7256, Aix-Marseille University, Centre National de la Recherche Scientifique, IMM, IM2B, 13288, Marseille Cedex 9, France
| | - Cristina De Castro
- Department of Agricultural Sciences, University of Naples Federico II, Via Università, 100, 80055, Portici (NA), Italy
| |
Collapse
|
5
|
Harvey DJ. NEGATIVE ION MASS SPECTROMETRY FOR THE ANALYSIS OF N-LINKED GLYCANS. Mass Spectrom Rev 2020; 39:586-679. [PMID: 32329121 DOI: 10.1002/mas.21622] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/13/2019] [Accepted: 12/22/2019] [Indexed: 05/03/2023]
Abstract
N-glycans from glycoproteins are complex, branched structures whose structural determination presents many analytical problems. Mass spectrometry, usually conducted in positive ion mode, often requires extensive sample manipulation, usually by derivatization such as permethylation, to provide the necessary structure-revealing fragment ions. The newer but, so far, lesser used negative ion techniques, on the contrary, provide a wealth of structural information not present in positive ion spectra that greatly simplify the analysis of these compounds and can usually be conducted without the need for derivatization. This review describes the use of negative ion mass spectrometry for the structural analysis of N-linked glycans and emphasises the many advantages that can be gained by this mode of operation. Biosynthesis and structures of the compounds are described followed by methods for release of the glycans from the protein. Methods for ionization are discussed with emphasis on matrix-assisted laser desorption/ionization (MALDI) and methods for producing negative ions from neutral compounds. Acidic glycans naturally give deprotonated species under most ionization conditions. Fragmentation of negative ions is discussed next with particular reference to those ions that are diagnostic for specific features such as the branching topology of the glycans and substitution positions of moieties such as fucose and sulfate, features that are often difficult to identify easily by conventional techniques such as positive ion fragmentation and exoglycosidase digestions. The advantages of negative over positive ions for this structural work are emphasised with an example of a series of glycans where all other methods failed to produce a structure. Fragmentation of derivatized glycans is discussed next, both with respect to derivatives at the reducing terminus of the molecules, and to methods for neutralization of the acidic groups on sialic acids to both stabilize them for MALDI analysis and to produce the diagnostic fragments seen with the neutral glycans. The use of ion mobility, combined with conventional mass spectrometry is described with emphasis on its use to extract clean glycan spectra both before and after fragmentation, to separate isomers and its use to extract additional information from separated fragment ions. A section on applications follows with examples of the identification of novel structures from lower organisms and tables listing the use of negative ions for structural identification of specific glycoproteins, glycans from viruses and uses in the biopharmaceutical industry and in medicine. The review concludes with a summary of the advantages and disadvantages of the technique. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
Collapse
Affiliation(s)
- David J Harvey
- Nuffield Department of Medicine, Target Discovery Institute, Roosevelt Drive, Oxford, OX3 7FZ, United Kingdom
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Life Sciences Building 85, Highfield Campus, Southampton, SO17 1BJ, United Kingdom
| |
Collapse
|
6
|
Illiano A, Pinto G, Melchiorre C, Carpentieri A, Faraco V, Amoresano A. Protein Glycosylation Investigated by Mass Spectrometry: An Overview. Cells 2020; 9:E1986. [PMID: 32872358 DOI: 10.3390/cells9091986] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/14/2020] [Accepted: 08/24/2020] [Indexed: 12/16/2022] Open
Abstract
The protein glycosylation is a post-translational modification of crucial importance for its involvement in molecular recognition, protein trafficking, regulation, and inflammation. Indeed, abnormalities in protein glycosylation are correlated with several disease states such as cancer, inflammatory diseases, and congenial disorders. The understanding of cellular mechanisms through the elucidation of glycan composition encourages researchers to find analytical solutions for their detection. Actually, the multiplicity and diversity of glycan structures bond to the proteins, the variations in polarity of the individual saccharide residues, and the poor ionization efficiencies make their detection much trickier than other kinds of biopolymers. An overview of the most prominent techniques based on mass spectrometry (MS) for protein glycosylation (glycoproteomics) studies is here presented. The tricks and pre-treatments of samples are discussed as a crucial step prodromal to the MS analysis to improve the glycan ionization efficiency. Therefore, the different instrumental MS mode is also explored for the qualitative and quantitative analysis of glycopeptides and the glycans structural composition, thus contributing to the elucidation of biological mechanisms.
Collapse
|
7
|
Ferek JD, Thoden JB, Holden HM. Biochemical analysis of a sugar 4,6-dehydratase from Acanthamoeba polyphaga Mimivirus. Protein Sci 2020; 29:1148-1159. [PMID: 32083779 DOI: 10.1002/pro.3843] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [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: 01/24/2020] [Revised: 02/17/2020] [Accepted: 02/17/2020] [Indexed: 02/06/2023]
Abstract
The exciting discovery of the giant DNA Mimivirus in 2003 challenged the conventional description of viruses in a radical way, and since then, dozens of additional giant viruses have been identified. It has now been demonstrated that the Mimivirus genome encodes for the two enzymes required for the production of the unusual sugar 4-amino-4,6-dideoxy-d-glucose, namely a 4,6-dehydratase and an aminotransferase. In light of our long-standing interest in the bacterial 4,6-dehydratases and in unusual sugars in general, we conducted a combined structural and functional analysis of the Mimivirus 4,6-dehydratase referred to as R141. For this investigation, the three-dimensional X-ray structure of R141 was determined to 2.05 Å resolution and refined to an R-factor of 18.3%. The overall fold of R141 places it into the short-chain dehydrogenase/reductase (SDR) superfamily of proteins. Whereas its molecular architecture is similar to that observed for the bacterial 4,6-dehydratases, there are two key regions where the polypeptide chain adopts different conformations. In particular, the conserved tyrosine that has been implicated as a catalytic acid or base in SDR superfamily members is splayed away from the active site by nearly 12 Å, thereby suggesting that a major conformational change must occur upon substrate binding. In addition to the structural analysis, the kinetic parameters for R141 using either dTDP-d-glucose or UDP-d-glucose as substrates were determined. Contrary to a previous report, R141 demonstrates nearly identical catalytic efficiency with either nucleotide-linked sugar. The data presented herein represent the first three-dimensional model for a viral 4,6-dehydratase and thus expands our understanding of these fascinating enzymes.
Collapse
Affiliation(s)
- Justin D Ferek
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - James B Thoden
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States
| | - Hazel M Holden
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin, United States
| |
Collapse
|
8
|
Khan A, Johnson George K, Jasrotia RS, Aravind S, Angadi UB, Iquebal MA, Manju KP, Jaiswal S, Umadevi P, Rai A, Kumar D. Plant virus interaction mechanism and associated pathways in mosaic disease of small cardamom (Elettaria cardamomum Maton) by RNA-Seq approach. Genomics 2020; 112:2041-51. [PMID: 31770586 DOI: 10.1016/j.ygeno.2019.11.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/29/2019] [Accepted: 11/22/2019] [Indexed: 11/21/2022]
Abstract
Small cardamom (Elettaria cardamomum), grown in limited coastal tropical countries is one of the costliest and widely exported agri-produce having global turnover of >10 billion USD. Mosaic/marble disease is one of the major impediments that requires understanding of disease at molecular level. Neither whole genome sequence nor any genomic resources are available, thus RNA seq approach can be a rapid and economical alternative. De novo transcriptome assembly was done with Illumina Hiseq data. A total of 5317 DEGs, 2267 TFs, 114 pathways and 175,952 genic region putative markers were obtained. Gene regulatory network analysis deciphered molecular events involved in marble disease. This is the first transcriptomic report revealing disease mechanism mediated by perturbation in auxin homeostasis and ethylene signalling leading to senescence. The web-genomic resource (SCMVTDb) catalogues putative molecular markers, candidate genes and transcript information. SCMVTDb can be used in germplasm improvement against mosaic disease in endeavour of small cardamom productivity. Availability of genomic resource, SCMVTDb: http://webtom.cabgrid.res.in/scmvtdb/.
Collapse
|
9
|
Watanabe Y, Bowden TA, Wilson IA, Crispin M. Exploitation of glycosylation in enveloped virus pathobiology. Biochim Biophys Acta Gen Subj 2019; 1863:1480-1497. [PMID: 31121217 PMCID: PMC6686077 DOI: 10.1016/j.bbagen.2019.05.012] [Citation(s) in RCA: 299] [Impact Index Per Article: 59.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/13/2019] [Accepted: 05/17/2019] [Indexed: 12/12/2022]
Abstract
Glycosylation is a ubiquitous post-translational modification responsible for a multitude of crucial biological roles. As obligate parasites, viruses exploit host-cell machinery to glycosylate their own proteins during replication. Viral envelope proteins from a variety of human pathogens including HIV-1, influenza virus, Lassa virus, SARS, Zika virus, dengue virus, and Ebola virus have evolved to be extensively glycosylated. These host-cell derived glycans facilitate diverse structural and functional roles during the viral life-cycle, ranging from immune evasion by glycan shielding to enhancement of immune cell infection. In this review, we highlight the imperative and auxiliary roles glycans play, and how specific oligosaccharide structures facilitate these functions during viral pathogenesis. We discuss the growing efforts to exploit viral glycobiology in the development of anti-viral vaccines and therapies.
Collapse
Affiliation(s)
- Yasunori Watanabe
- School of Biological Sciences and Institute of Life Sciences, University of Southampton, Southampton SO17 1BJ, UK; Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford OX3 7BN, UK; Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Thomas A Bowden
- Division of Structural Biology, University of Oxford, Wellcome Centre for Human Genetics, Oxford OX3 7BN, UK
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Max Crispin
- School of Biological Sciences and Institute of Life Sciences, University of Southampton, Southampton SO17 1BJ, UK.
| |
Collapse
|
10
|
Speciale I, Duncan GA, Unione L, Agarkova IV, Garozzo D, Jimenez-Barbero J, Lin S, Lowary TL, Molinaro A, Noel E, Laugieri ME, Tonetti MG, Van Etten JL, De Castro C. The N-glycan structures of the antigenic variants of chlorovirus PBCV-1 major capsid protein help to identify the virus-encoded glycosyltransferases. J Biol Chem 2019; 294:5688-5699. [PMID: 30737276 DOI: 10.1074/jbc.ra118.007182] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [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: 12/16/2018] [Revised: 02/07/2019] [Indexed: 11/06/2022] Open
Abstract
The chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) is a large dsDNA virus that infects the microalga Chlorella variabilis NC64A. Unlike most other viruses, PBCV-1 encodes most, if not all, of the machinery required to glycosylate its major capsid protein (MCP). The structures of the four N-linked glycans from the PBCV-1 MCP consist of nonasaccharides, and similar glycans are not found elsewhere in the three domains of life. Here, we identified the roles of three virus-encoded glycosyltransferases (GTs) that have four distinct GT activities in glycan synthesis. Two of the three GTs were previously annotated as GTs, but the third GT was identified in this study. We determined the GT functions by comparing the WT glycan structures from PBCV-1 with those from a set of PBCV-1 spontaneous GT gene mutants resulting in antigenic variants having truncated glycan structures. According to our working model, the virus gene a064r encodes a GT with three domains: domain 1 has a β-l-rhamnosyltransferase activity, domain 2 has an α-l-rhamnosyltransferase activity, and domain 3 is a methyltransferase that decorates two positions in the terminal α-l-rhamnose (Rha) unit. The a075l gene encodes a β-xylosyltransferase that attaches the distal d-xylose (Xyl) unit to the l-fucose (Fuc) that is part of the conserved N-glycan core region. Last, gene a071r encodes a GT that is involved in the attachment of a semiconserved element, α-d-Rha, to the same l-Fuc in the core region. Our results uncover GT activities that assemble four of the nine residues of the PBCV-1 MCP N-glycans.
Collapse
Affiliation(s)
- Immacolata Speciale
- From the Department of Agricultural Sciences, University of Napoli Federico II, Via Università 100, 80055 Portici NA, Italy
| | - Garry A Duncan
- the Department of Biology, Nebraska Wesleyan University, Lincoln, Nebraska 68504-2794
| | - Luca Unione
- the Chemical Glycobiology Lab, CIC bioGUNE, Bizkaia Technology Park, Bld 800, 48170 Derio, Spain
| | - Irina V Agarkova
- the Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska 68583-0900.,the Department of Plant Pathology, University of Nebraska, Lincoln, Nebraska 68583-0722
| | - Domenico Garozzo
- Institute for Polymers, Composites, and Biomaterials, CNR, Via P. Gaifami 18, 95126 Catania, Italy
| | - Jesus Jimenez-Barbero
- the Chemical Glycobiology Lab, CIC bioGUNE, Bizkaia Technology Park, Bld 800, 48170 Derio, Spain.,the Basque Foundation for Science (IKERBASQUE), 48940 Bilbao, Spain.,the Department of Organic Chemistry II, Faculty of Science and Technology, University of the Basque Country, EHU-UPV, 48940 Leioa, Spain
| | - Sicheng Lin
- the Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Gunning-Lemieux Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada
| | - Todd L Lowary
- the Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Gunning-Lemieux Chemistry Centre, Edmonton, Alberta T6G 2G2, Canada
| | - Antonio Molinaro
- the Department of Chemical Sciences, Università of Napoli Federico II, 80126 Napoli, Italy
| | - Eric Noel
- the Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska 68583-0900.,the School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0118, and
| | - Maria Elena Laugieri
- the Department of Experimental Medicine and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV/1, 16132 Genova, Italy
| | - Michela G Tonetti
- the Department of Experimental Medicine and Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV/1, 16132 Genova, Italy
| | - James L Van Etten
- the Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska 68583-0900, .,the Department of Plant Pathology, University of Nebraska, Lincoln, Nebraska 68583-0722
| | - Cristina De Castro
- From the Department of Agricultural Sciences, University of Napoli Federico II, Via Università 100, 80055 Portici NA, Italy,
| |
Collapse
|
11
|
Affiliation(s)
- David J. Harvey
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Biological Sciences and the Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| |
Collapse
|