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Barker MK, Rose DR. Specificity of Processing α-glucosidase I is guided by the substrate conformation: crystallographic and in silico studies. J Biol Chem 2013; 288:13563-74. [PMID: 23536181 DOI: 10.1074/jbc.m113.460436] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The enzyme “GluI” is key to the synthesis of critical glycoproteins in the cell. RESULTS We have determined the structure of GluI, and modeled binding with its unique sugar substrate. CONCLUSION The specificity of this interaction derives from a unique conformation of the substrate. SIGNIFICANCE Understanding the mechanism of the enzyme is of basic importance and relevant to potential development of antiviral inhibitors. Processing α-glucosidase I (GluI) is a key member of the eukaryotic N-glycosylation processing pathway, selectively catalyzing the first glycoprotein trimming step in the endoplasmic reticulum. Inhibition of GluI activity impacts the infectivity of enveloped viruses; however, despite interest in this protein from a structural, enzymatic, and therapeutic standpoint, little is known about its structure and enzymatic mechanism in catalysis of the unique glycan substrate Glc3Man9GlcNAc2. The first structural model of eukaryotic GluI is here presented at 2-Å resolution. Two catalytic residues are proposed, mutations of which result in catalytically inactive, properly folded protein. Using Autodocking methods with the known substrate and inhibitors as ligands, including a novel inhibitor characterized in this work, the active site of GluI was mapped. From these results, a model of substrate binding has been formulated, which is most likely conserved in mammalian GluI.
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Affiliation(s)
- Megan K Barker
- Department of Medical Biophysics, University of Toronto, Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario M5G 2M9, Canada.
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352
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Xu R, Krause JC, McBride R, Paulson JC, Crowe JE, Wilson IA. A recurring motif for antibody recognition of the receptor-binding site of influenza hemagglutinin. Nat Struct Mol Biol 2013; 20:363-70. [PMID: 23396351 PMCID: PMC3594569 DOI: 10.1038/nsmb.2500] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Accepted: 12/26/2012] [Indexed: 11/21/2022]
Abstract
Influenza virus hemagglutinin (HA) mediates receptor binding and viral entry during influenza infection. The development of receptor analogs as viral-entry blockers has not been successful, which suggests that sialic acid may not be an ideal scaffold to obtain broad, potent HA inhibitors. Here, we report crystal structures of Fab fragments from three human antibodies that neutralize the 1957 pandemic H2N2 influenza virus in complex with H2 HA. All three antibodies use an aromatic residue to plug a conserved cavity in the HA receptor-binding site. Each antibody interacts with the absolutely conserved HA1 Trp153 at the cavity base through π-π stacking with the signature Phe54 of two VH1-69-encoded antibodies or a tyrosine from HCDR3 in the other antibody. This highly conserved interaction can be used as a starting point to design inhibitors targeting this conserved hydrophobic pocket in influenza viruses.
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Affiliation(s)
- Rui Xu
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Jens C. Krause
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Ryan McBride
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, USA
| | - James C. Paulson
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, USA
| | - James E. Crowe
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Ian A. Wilson
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
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353
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Virulent feline calicivirus disease in a shelter in Italy: a case description. Res Vet Sci 2013; 95:283-90. [PMID: 23433681 PMCID: PMC7111799 DOI: 10.1016/j.rvsc.2013.01.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 01/07/2013] [Accepted: 01/25/2013] [Indexed: 12/22/2022]
Abstract
Feline calicivirus (FCV) is a common pathogen of cats that is particularly widespread in multi-cat environments such as shelters and catteries. FCV infections are usually associated with acute, mild and self-limiting upper respiratory tract disease characterized by oral vesicles/ulcers. Recently, virulent systemic disease (VSD) associated with FCV infection has been reported in the USA and Europe. This paper describes a case of VSD affecting one adult, FIV infected cat ("Oscar") living in a shelter located in Northern Italy; the clinical, post-mortem and laboratory findings indicate that this is the first case of suspected FCV-VSD in this country. Similar to a previous report (Meyer et al., 2011), the disease affected only one cat, while others remained asymptomatic, despite their direct contact with "Oscar". Phylogenetic analysis identified unique features in the "Oscar" FCV isolate. The FIV infection of the patient might have favoured the generation of the virulent FCV strains in this cat.
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354
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Job ER, Deng YM, Barfod KK, Tate MD, Caldwell N, Reddiex S, Maurer-Stroh S, Brooks AG, Reading PC. Addition of glycosylation to influenza A virus hemagglutinin modulates antibody-mediated recognition of H1N1 2009 pandemic viruses. THE JOURNAL OF IMMUNOLOGY 2013; 190:2169-77. [PMID: 23365085 DOI: 10.4049/jimmunol.1202433] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Seasonal influenza A viruses (IAV) originate from pandemic IAV and have undergone changes in antigenic structure, including addition of glycans to the viral hemagglutinin (HA). Glycans on the head of HA promote virus survival by shielding antigenic sites, but highly glycosylated seasonal IAV are inactivated by soluble lectins of the innate immune system. In 2009, human strains of pandemic H1N1 [A(H1N1)pdm] expressed a single glycosylation site (Asn(104)) on the head of HA. Since then, variants with additional glycosylation sites have been detected, and the location of these sites has been distinct to those of recent seasonal H1N1 strains. We have compared wild-type and reverse-engineered A(H1N1)pdm IAV with differing potential glycosylation sites on HA for sensitivity to collectins and to neutralizing Abs. Addition of a glycan (Asn(136)) to A(H1N1)pdm HA was associated with resistance to neutralizing Abs but did not increase sensitivity to collectins. Moreover, variants expressing Asn(136) showed enhanced growth in A(H1N1)pdm-vaccinated mice, consistent with evasion of Ab-mediated immunity in vivo. Thus, a fine balance exists regarding the optimal pattern of HA glycosylation to facilitate evasion of Ab-mediated immunity while maintaining resistance to lectin-mediated defenses of the innate immune system.
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Affiliation(s)
- Emma R Job
- Department of Microbiology and Immunology, University of Melbourne, Melbourne 3010, Victoria, Australia
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355
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Springer SA, Gagneux P. Glycan evolution in response to collaboration, conflict, and constraint. J Biol Chem 2013; 288:6904-11. [PMID: 23329843 DOI: 10.1074/jbc.r112.424523] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycans, oligo- and polysaccharides secreted or attached to proteins and lipids, cover the surfaces of all cells and have a regulatory capacity and structural diversity beyond any other class of biological molecule. Glycans may have evolved these properties because they mediate cellular interactions and often face pressure to evolve new functions rapidly. We approach this idea two ways. First, we discuss evolutionary innovation. Glycan synthesis, regulation, and mode of chemical interaction influence the spectrum of new forms presented to evolution. Second, we describe the evolutionary conflicts that arise when alleles and individuals interact. Glycan regulation and diversity are integral to these biological negotiations. Glycans are tasked with such an amazing diversity of functions that no study of cellular interaction can begin without considering them. We propose that glycans predominate the cell surface because their physical and chemical properties allow the rapid innovation required of molecules on the frontlines of evolutionary conflict.
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Affiliation(s)
- Stevan A Springer
- Glycobiology Research and Training Center and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093-0687 USA
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356
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Nothaft H, Szymanski CM. Bacterial protein N-glycosylation: new perspectives and applications. J Biol Chem 2013; 288:6912-20. [PMID: 23329827 DOI: 10.1074/jbc.r112.417857] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein glycosylation is widespread throughout all three domains of life. Bacterial protein N-glycosylation and its application to engineering recombinant glycoproteins continue to be actively studied. Here, we focus on advances made in the last 2 years, including the characterization of novel bacterial N-glycosylation pathways, examination of pathway enzymes and evolution, biological roles of protein modification in the native host, and exploitation of the N-glycosylation pathways to create novel vaccines and diagnostics.
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Affiliation(s)
- Harald Nothaft
- Alberta Glycomics Centre and Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
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357
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Delgui LR, Rodríguez JF. Virus maturation. Subcell Biochem 2013; 68:395-415. [PMID: 23737059 DOI: 10.1007/978-94-007-6552-8_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The formation of infectious virus particles is a highly complex process involving a series of sophisticated molecular events. In most cases, the assembly of virus structural elements results in the formation of immature virus particles unable to initiate a productive infection. Accordingly, for most viruses the final stage of the assembly pathway entails a set of structural transitions and/or biochemical modifications that transform inert precursor particles into fully infectious agents. In this chapter, we review the most relevant maturation mechanisms involved in the generation of infectious virions for a wide variety of viruses.
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Affiliation(s)
- Laura R Delgui
- Laboratorio de Biología Celular y Molecular, Instituto de Histología y Embriología Mendoza (IHEM), Facultad de Ciencias Médicas, Instituto de Ciencias Básicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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358
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Theillet FX, Smet-Nocca C, Liokatis S, Thongwichian R, Kosten J, Yoon MK, Kriwacki RW, Landrieu I, Lippens G, Selenko P. Cell signaling, post-translational protein modifications and NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2012; 54:217-36. [PMID: 23011410 PMCID: PMC4939263 DOI: 10.1007/s10858-012-9674-x] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 09/07/2012] [Indexed: 05/13/2023]
Abstract
Post-translationally modified proteins make up the majority of the proteome and establish, to a large part, the impressive level of functional diversity in higher, multi-cellular organisms. Most eukaryotic post-translational protein modifications (PTMs) denote reversible, covalent additions of small chemical entities such as phosphate-, acyl-, alkyl- and glycosyl-groups onto selected subsets of modifiable amino acids. In turn, these modifications induce highly specific changes in the chemical environments of individual protein residues, which are readily detected by high-resolution NMR spectroscopy. In the following, we provide a concise compendium of NMR characteristics of the main types of eukaryotic PTMs: serine, threonine, tyrosine and histidine phosphorylation, lysine acetylation, lysine and arginine methylation, and serine, threonine O-glycosylation. We further delineate the previously uncharacterized NMR properties of lysine propionylation, butyrylation, succinylation, malonylation and crotonylation, which, altogether, define an initial reference frame for comprehensive PTM studies by high-resolution NMR spectroscopy.
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Affiliation(s)
- Francois-Xavier Theillet
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
| | - Caroline Smet-Nocca
- CNRS UMR 8576, Universite Lille Nord de France, 59655 Villeneuve d’Ascq, France
| | - Stamatios Liokatis
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
| | - Rossukon Thongwichian
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
| | - Jonas Kosten
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
| | - Mi-Kyung Yoon
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Richard W. Kriwacki
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Isabelle Landrieu
- CNRS UMR 8576, Universite Lille Nord de France, 59655 Villeneuve d’Ascq, France
| | - Guy Lippens
- CNRS UMR 8576, Universite Lille Nord de France, 59655 Villeneuve d’Ascq, France
| | - Philipp Selenko
- Department of NMR-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), In-cell NMR Group, Robert-Roessle Strasse 10, 13125 Berlin, German
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359
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Chen W, Zhong Y, Qin Y, Sun S, Li Z. The evolutionary pattern of glycosylation sites in influenza virus (H5N1) hemagglutinin and neuraminidase. PLoS One 2012; 7:e49224. [PMID: 23133677 PMCID: PMC3486865 DOI: 10.1371/journal.pone.0049224] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 10/04/2012] [Indexed: 11/21/2022] Open
Abstract
Two glycoproteins, hemagglutinin (HA) and neuraminidase (NA), on the surface of influenza viruses play crucial roles in transfaunation, membrane fusion and the release of progeny virions. To explore the distribution of N-glycosylation sites (glycosites) in these two glycoproteins, we collected and aligned the amino acid sequences of all the HA and NA subtypes. Two glycosites were located at HA0 cleavage sites and fusion peptides and were strikingly conserved in all HA subtypes, while the remaining glycosites were unique to their subtypes. Two to four conserved glycosites were found in the stalk domain of NA, but these are affected by the deletion of specific stalk domain sequences. Another highly conserved glycosite appeared at the top center of tetrameric global domain, while the others glycosites were distributed around the global domain. Here we present a detailed investigation of the distribution and the evolutionary pattern of the glycosites in the envelope glycoproteins of IVs, and further focus on the H5N1 virus and conclude that the glycosites in H5N1 have become more complicated in HA and less influential in NA in the last five years.
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Affiliation(s)
- Wentian Chen
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Yaogang Zhong
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Yannan Qin
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Shisheng Sun
- Department of Pathology, Clinical Chemistry Division, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Zheng Li
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
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360
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Crucial role of the N-glycans on the viral E-envelope glycoprotein in DC-SIGN-mediated dengue virus infection. Antiviral Res 2012; 96:280-7. [PMID: 23124109 DOI: 10.1016/j.antiviral.2012.10.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 10/16/2012] [Accepted: 10/21/2012] [Indexed: 12/17/2022]
Abstract
We generated in the mosquito cell line C6/36 a dengue virus (DENV) resistant to Hippeastrum hybrid agglutinin (HHA), a carbohydrate-binding agent (CBA). The genotype and phenotype were characterized of the HHA resistant (HHA(res)) DENV compared to the wild-type (WT) DENV. Sequencing the structural proteins of HHA(res) resulted in two mutations, N67D and T155I, indicating a deletion of both N-glycosylation sites on the viral envelope E-glycoprotein. The HHA(res) DENV could replicate in mammalian and mosquito cells that are lacking dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) expression. In contrast, DC-SIGN expressing human cells namely monocyte-derived dendritic cells as well as DC-SIGN-transfected cells were no longer susceptible to HHA(res) DENV. This demonstrates a crucial role of the N-glycans in the E-glycoprotein in the infection of dendritic cells, which constitute primary target cells of DENV during viral pathogenesis in the human body.
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361
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Kropff B, Burkhardt C, Schott J, Nentwich J, Fisch T, Britt W, Mach M. Glycoprotein N of human cytomegalovirus protects the virus from neutralizing antibodies. PLoS Pathog 2012; 8:e1002999. [PMID: 23133379 PMCID: PMC3486915 DOI: 10.1371/journal.ppat.1002999] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 09/11/2012] [Indexed: 11/19/2022] Open
Abstract
Herpes viruses persist in the infected host and are transmitted between hosts in the presence of a fully functional humoral immune response, suggesting that they can evade neutralization by antiviral antibodies. Human cytomegalovirus (HCMV) encodes a number of polymorphic highly glycosylated virion glycoproteins (g), including the essential envelope glycoprotein, gN. We have tested the hypothesis that glycosylation of gN contributes to resistance of the virus to neutralizing antibodies. Recombinant viruses carrying deletions in serine/threonine rich sequences within the glycosylated surface domain of gN were constructed in the genetic background of HCMV strain AD169. The deletions had no influence on the formation of the gM/gN complex and in vitro replication of the respective viruses compared to the parent virus. The gN-truncated viruses were significantly more susceptible to neutralization by a gN-specific monoclonal antibody and in addition by a number of gB- and gH-specific monoclonal antibodies. Sera from individuals previously infected with HCMV also more efficiently neutralized gN-truncated viruses. Immunization of mice with viruses that expressed the truncated forms of gN resulted in significantly higher serum neutralizing antibody titers against the homologous strain that was accompanied by increased antibody titers against known neutralizing epitopes on gB and gH. Importantly, neutralization activity of sera from animals immunized with gN-truncated virus did not exhibit enhanced neutralizing activity against the parental wild type virus carrying the fully glycosylated wild type gN. Our results indicate that the extensive glycosylation of gN could represent a potentially important mechanism by which HCMV neutralization by a number of different antibody reactivities can be inhibited. Herpes viruses are transmitted between individuals in cell free form and successful spread benefits from mechanisms that limit the loss of infectivity by the activity of virus neutralizing antibodies. Human cytomegalovirus (HCMV) is an important pathogen and understanding how the virus can evade antiviral antibodies may be clinically relevant. HCMV particles contain a number of highly polymorphic, extensively glycosylated envelope proteins, one of which is glycoprotein N (gN). This protein is essential for replication of HCMV. We have hypothesized that the extensive glycosylation of gN may serve as a tool to evade neutralization by antiviral antibodies. Recombinant viruses were generated expressing gN proteins with reduced glycan modification. The loss of glycan modification had no detectable influence on the in vitro replication of the respective viruses. However, the recombinant viruses containing under-glycosylated forms of gN were significantly more susceptible to neutralization by a diverse array of antibody reactivities. Immunization of mice with viruses carrying fewer glycan modification induced significantly higher antibody titers against the homologous virus; however, the neutralization titers against the fully glycosylated virions, were not enhanced. Our results indicate that glycosylation of gN of HCMV represents a potentially important mechanism for evasion of antibody-mediated neutralization by a number of different antibody specificities.
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Affiliation(s)
- Barbara Kropff
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität, Erlangen-Nürnberg, Germany
| | - Christiane Burkhardt
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität, Erlangen-Nürnberg, Germany
| | - Juliane Schott
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität, Erlangen-Nürnberg, Germany
| | - Jens Nentwich
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität, Erlangen-Nürnberg, Germany
| | - Tanja Fisch
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität, Erlangen-Nürnberg, Germany
| | - William Britt
- Department of Pediatrics, University of Alabama Birmingham, Birmingham, Alabama, United States of America
| | - Michael Mach
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander-Universität, Erlangen-Nürnberg, Germany
- * E-mail:
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362
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Structural and functional characterization of neuraminidase-like molecule N10 derived from bat influenza A virus. Proc Natl Acad Sci U S A 2012; 109:18897-902. [PMID: 23012237 DOI: 10.1073/pnas.1211037109] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The recent discovery of the unique genome of influenza virus H17N10 in bats raises considerable doubt about the origin and evolution of influenza A viruses. It also identifies a neuraminidase (NA)-like protein, N10, that is highly divergent from the nine other well-established serotypes of influenza A NA (N1-N9). The structural elucidation and functional characterization of influenza NAs have illustrated the complexity of NA structures, thus raising a key question as to whether N10 has a special structure and function. Here the crystal structure of N10, derived from influenza virus A/little yellow-shouldered bat/Guatemala/153/2009 (H17N10), was solved at a resolution of 2.20 Å. Overall, the structure of N10 was found to be similar to that of the other known influenza NA structures. In vitro enzymatic assays demonstrated that N10 lacks canonical NA activity. A detailed structural analysis revealed dramatic alterations of the conserved active site residues that are unfavorable for the binding and cleavage of terminally linked sialic acid receptors. Furthermore, an unusual 150-loop (residues 147-152) was observed to participate in the intermolecular polar interactions between adjacent N10 molecules of the N10 tetramer. Our study of influenza N10 provides insight into the structure and function of the sialidase superfamily and sheds light on the molecular mechanism of bat influenza virus infection.
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363
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Abro SH, Ullman K, Belák S, Baule C. Bioinformatics and evolutionary insight on the spike glycoprotein gene of QX-like and Massachusetts strains of infectious bronchitis virus. Virol J 2012; 9:211. [PMID: 22992336 PMCID: PMC3502414 DOI: 10.1186/1743-422x-9-211] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 09/07/2012] [Indexed: 11/12/2022] Open
Abstract
Background Infectious bronchitis virus (IBV) is a Gammacoronavirus of the family Coronaviridae and is a causative agent of an economically important disease in poultry. The spike glycoprotein of IBV is essential for host cell attachment, neutralization, and is involved in the induction of protective immunity. Previously obtained sequence data of the spike gene of IBV QX-like and Massachusetts strains were subjected to bioinformatics analysis. Findings On analysis of potential phosphorylation sites, the Ser542 and Ser563 sites were not present in Massachusetts strains, while QX-like isolates did not have the Ser534 site. Massachusetts and QX-like strains showed different cleavage site motifs. The N-glycosylation sites ASN-XAA-SER/THR-55, 147, 200 and 545 were additionally present in QX-like strains. The leucine-rich repeat regions in Massachusetts strains consisted of stretches of 63 to 69 amino acids, while in the QX-like strains they contained 59 amino acids in length. An additional palmitoylation site was observed in CK/SWE/082066/2010 a QX-like strain. Primary structure data showed difference in the physical properties and hydrophobic nature of both genotypes. The comparison of secondary structures revealed no new structural domains in the genotypic variants. The phylogenetic analyses based on avian and mammalian coronaviruses showed the analysed IBV as closely related to turkey coronaviruses and distantly related to thrush and munia coronaviruses. Conclusion The study demonstrated that spike glycoprotein of the Massachusetts and the QX-like variants of IBV are molecularly distinct and that this may reflect in differences in the behavior of these viruses in vivo.
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Affiliation(s)
- Shahid Hussain Abro
- Department of Biomedical Sciences and Veterinary Public Health, Section of Virology, The Swedish University of Agricultural Sciences, Ulls Väg 2B, SE-751 89, Uppsala, Sweden.
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364
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Vigerust DJ, Vick S, Shepherd VL. Characterization of functional mannose receptor in a continuous hybridoma cell line. BMC Immunol 2012; 13:51. [PMID: 22967244 PMCID: PMC3495026 DOI: 10.1186/1471-2172-13-51] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 08/30/2012] [Indexed: 12/29/2022] Open
Abstract
Background The mannose receptor is the best described member of the type I transmembrane C-type lectins; however much remains unanswered about the biology of the receptor. One difficulty has been the inability to consistently express high levels of a functional full length mannose receptor cDNA in mammalian cells. Another difficulty has been the lack of a human macrophage cell line expressing a fully functional receptor. Commonly used human macrophage cell lines such as U937, THP-1, Mono-Mac and HL60 do not express the mannose receptor. We have developed a macrophage hybridoma cell line (43MR cells) created by fusion of U937 cells with primary human monocyte-derived macrophages, resulting in a non-adherent cell line expressing several properties of primary macrophages. The purpose of this study was to identify and select mannose receptor-expressing cells using fluorescence-activated cell sorting and to characterize the expression and function of the receptor. Results In the current study we show that the mannose receptor found on this novel cell has endocytic characteristics consistent with and similar to the mannose receptor found on the surface of monocyte-derived human macrophages and rat bone marrow-derived macrophages. In addition, we demonstrate that these cells engage and internalize pathogen particles such as S. aureus and C. albicans. We further establish the transfectability of these cells via the introduction of a plasmid expressing influenza A hemagglutinin. Conclusions The 43MR cell line represents the first naturally expressed MR-positive cell line derived from a human macrophage background. This cell line provides an important cell model for other researchers for the study of human MR biology and host-pathogen interactions.
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Affiliation(s)
- David J Vigerust
- Department of Veterans Affairs Medical Center, VA Medical Center/Research Service, 1310 24th Ave,, South, Nashville TN 37212, USA
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365
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Abstract
Since the 1918 influenza A virus (IAV) pandemic, H1N1 viruses have circulated in human populations. The hemagglutinin (HA) of IAV determines viral antigenicity and often undergoes N-linked glycosylation (NLG) at several sites. Interestingly, structural analysis of the 1918 and 2009 H1N1 pandemic viruses revealed antigenic similarities attributable to the conserved epitopes and the NLG statuses of their HA proteins. NLG of the globular head of HA is known to modulate the antigenicity, fusion activity, virulence, receptor-binding specificity, and immune evasion of IAV. In addition, the HA of IAV often retains additional mutations. These supplemental mutations compensate for the attenuation of viral properties resulting from the introduced NLG. In human H1N1 viruses, the number and location of NLG sites has been regulated in accordance with the antigenic variability of the NLG-targeted antibody-binding site. The relationship between the NLG and the antigenic variance in HA appears to be stably controlled in the viral context.
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Affiliation(s)
- Jin Il Kim
- Department of Microbiology, Center for Medical Science Research, College of Medicine, Hallym University, Chuncheon, Korea
| | - Man-Seong Park
- Department of Microbiology, Center for Medical Science Research, College of Medicine, Hallym University, Chuncheon, Korea
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366
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Proteomic footprints of a member of Glossinavirus (Hytrosaviridae): an expeditious approach to virus control strategies in tsetse factories. J Invertebr Pathol 2012; 112 Suppl:S26-31. [PMID: 22841943 DOI: 10.1016/j.jip.2012.07.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 05/14/2012] [Accepted: 05/17/2012] [Indexed: 11/21/2022]
Abstract
The Glossinavirus (Glossina pallidipes salivary gland hypertrophy virus (GpSGHV)) is a rod-shaped enveloped insect virus containing a 190,032 bp-long, circular dsDNA genome. The virus is pathogenic for the tsetse fly Glossina pallidipes and has been associated with the collapse of selected mass-reared colonies. Maintenance of productive fly colonies is critical to tsetse and trypanosomiasis eradication in sub-Saharan Africa using the Sterile Insect Technique. Proteomics, an approach to define the expressed protein complement of a genome, was used to further our understanding of the protein composition, morphology, morphogenesis and pathology of GpSGHV. Additionally, this approach provides potential targets for novel and sustainable molecular-based antiviral strategies to control viral infections in tsetse colonies. To achieve this goal, identification of key protein partners involved in virus transmission is required. In this review, we integrate the available data on GpSGHV proteomics to assess the impact of viral infections on host metabolism and to understand the contributions of such perturbations to viral pathogenesis. The relevance of the proteome findings to tsetse and trypanosomiasis management in sub-Sahara Africa is also considered.
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367
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Gu J, Cao R, Zhang Y, Lian X, Ishag H, Chen P. Deletion of the single putative N-glycosylation site of the porcine circovirus type 2 Cap protein enhances specific immune responses by DNA immunisation in mice. Vet J 2012; 192:385-9. [DOI: 10.1016/j.tvjl.2011.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 06/09/2011] [Accepted: 08/08/2011] [Indexed: 10/16/2022]
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368
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Santiago FW, Lambert Emo K, Fitzgerald T, Treanor JJ, Topham DJ. Antigenic and immunogenic properties of recombinant hemagglutinin proteins from H1N1 A/Brisbane/59/07 and B/Florida/04/06 when produced in various protein expression systems. Vaccine 2012; 30:4606-16. [PMID: 22609035 DOI: 10.1016/j.vaccine.2012.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 03/27/2012] [Accepted: 05/01/2012] [Indexed: 10/28/2022]
Abstract
Antibodies directed against the influenza hemagglutinin (HA) protein largely mediate virus neutralization and confer protection against infection. Consequently, many studies and assays of influenza vaccines are focused on HA-specific immune responses. Recombinant HA (rHA) proteins can be produced in a number of protein expression and cell culture systems. These range from baculovirus infection of insect cell cultures, to transient transfection of plants, to stably transfected human cell lines. Furthermore, the rHA proteins may contain genetic modifications, such as histidine tags or trimerization domains, intended to ease purification or enhance protein stability. However, no systematic study of these different forms of the HA protein have been conducted. It is not clear which, if any, of these different protein expression systems or structural modifications improve or diminish the biological behavior of the proteins as immunogens or antigens in immune assays. Therefore we set out to perform systematic evaluation of rHA produced in different proteins expression systems and with varied modifications. Five rHA proteins based on recent strains of seasonal influenza A and five based on influenza B HA were kindly provided by the Biodefense and Emerging Infections Reagent Repository (BEIR). These proteins were evaluated in a combination of biochemical and structural assays, in vitro humoral and cellular immune assays, and in an animal vaccination model. Marked differences in the behavior of the individual proteins was evident suggesting that they are not equal when being used to detect an immune response. They were, nevertheless, similar at eliciting neutralizing antibody responses.
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Affiliation(s)
- Felix W Santiago
- New York Influenza Center of Excellence, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 609, Rochester, NY 14642, USA. felix
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369
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YASMON ANDI, MUHAYAR YULIANTY, SETIAWATY VIVI, ERNAWATI DEWI BETI, BELA BUDIMAN, IBRAHIM FERA. Five Unique Amino Acid Residues of Hemagglutinin (HA) Proteins of Swine Influenza A (H1N1) Detected in 2009 in Jakarta, Indonesia. MICROBIOLOGY INDONESIA 2012. [DOI: 10.5454/mi.6.2.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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370
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Panaampon J, Ngaosuwankul N, Suptawiwat O, Noisumdaeng P, Sangsiriwut K, Siridechadilok B, Lerdsamran H, Auewarakul P, Pooruk P, Puthavathana P. A novel pathogenic mechanism of highly pathogenic avian influenza H5N1 viruses involves hemagglutinin mediated resistance to serum innate inhibitors. PLoS One 2012; 7:e36318. [PMID: 22563489 PMCID: PMC3341361 DOI: 10.1371/journal.pone.0036318] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 04/02/2012] [Indexed: 12/15/2022] Open
Abstract
In this study, the effect of innate serum inhibitors on influenza virus infection was addressed. Seasonal influenza A(H1N1) and A(H3N2), 2009 pandemic A(H1N1) (H1N1pdm) and highly pathogenic avian influenza (HPAI) A(H5N1) viruses were tested with guinea pig sera negative for antibodies against all of these viruses as evaluated by hemagglutination-inhibition and microneutralization assays. In the presence of serum inhibitors, the infection by each virus was inhibited differently as measured by the amount of viral nucleoprotein produced in Madin-Darby canine kidney cells. The serum inhibitors inhibited seasonal influenza A(H3N2) virus the most, while the effect was less in seasonal influenza A(H1N1) and H1N1pdm viruses. The suppression by serum inhibitors could be reduced by heat inactivation or treatment with receptor destroying enzyme. In contrast, all H5N1 strains tested were resistant to serum inhibitors. To determine which structure (hemagglutinin (HA) and/or neuraminidase (NA)) on the virus particles that provided the resistance, reverse genetics (rg) was applied to construct chimeric recombinant viruses from A/Puerto Rico/8/1934(H1N1) (PR8) plasmid vectors. rgPR8-H5 HA and rgPR8-H5 HANA were resistant to serum inhibitors while rgPR8-H5 NA and PR8 A(H1N1) parental viruses were sensitive, suggesting that HA of HPAI H5N1 viruses bestowed viral resistance to serum inhibition. These results suggested that the ability to resist serum inhibition might enable the viremic H5N1 viruses to disseminate to distal end organs. The present study also analyzed for correlation between susceptibility to serum inhibitors and number of glycosylation sites present on the globular heads of HA and NA. H3N2 viruses, the subtype with highest susceptibility to serum inhibitors, harbored the highest number of glycosylation sites on the HA globular head. However, this positive correlation cannot be drawn for the other influenza subtypes.
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MESH Headings
- Animals
- Antigens, Viral/chemistry
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Birds
- Cell Line
- Glycosylation
- Guinea Pigs
- Hemagglutinin Glycoproteins, Influenza Virus/chemistry
- Hemagglutinin Glycoproteins, Influenza Virus/genetics
- Hemagglutinin Glycoproteins, Influenza Virus/immunology
- Hot Temperature
- Humans
- Influenza A Virus, H1N1 Subtype/chemistry
- Influenza A Virus, H1N1 Subtype/immunology
- Influenza A Virus, H3N2 Subtype/chemistry
- Influenza A Virus, H3N2 Subtype/immunology
- Influenza A Virus, H5N1 Subtype/genetics
- Influenza A Virus, H5N1 Subtype/immunology
- Influenza A Virus, H5N1 Subtype/pathogenicity
- Influenza in Birds/virology
- Influenza, Human/virology
- Models, Molecular
- Protein Structure, Tertiary
- Recombinant Proteins/immunology
- Serum/immunology
- Virulence/immunology
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Affiliation(s)
- Jutatip Panaampon
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Center for Emerging and Neglected Infectious Disease, Mahidol University, Bangkok, Thailand
| | - Nathamon Ngaosuwankul
- Center for Emerging and Neglected Infectious Disease, Mahidol University, Bangkok, Thailand
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ornpreya Suptawiwat
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Center for Emerging and Neglected Infectious Disease, Mahidol University, Bangkok, Thailand
| | - Pirom Noisumdaeng
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Center for Emerging and Neglected Infectious Disease, Mahidol University, Bangkok, Thailand
| | - Kantima Sangsiriwut
- Department of Preventive Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | | | - Hatairat Lerdsamran
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Center for Emerging and Neglected Infectious Disease, Mahidol University, Bangkok, Thailand
| | - Prasert Auewarakul
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Center for Emerging and Neglected Infectious Disease, Mahidol University, Bangkok, Thailand
| | - Phisanu Pooruk
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Pilaipan Puthavathana
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Center for Emerging and Neglected Infectious Disease, Mahidol University, Bangkok, Thailand
- * E-mail:
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371
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Kandiba L, Aitio O, Helin J, Guan Z, Permi P, Bamford DH, Eichler J, Roine E. Diversity in prokaryotic glycosylation: an archaeal-derived N-linked glycan contains legionaminic acid. Mol Microbiol 2012; 84:578-93. [PMID: 22435790 DOI: 10.1111/j.1365-2958.2012.08045.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
VP4, the major structural protein of the haloarchaeal pleomorphic virus, HRPV-1, is glycosylated. To define the glycan structure attached to this protein, oligosaccharides released by β-elimination were analysed by mass spectrometry and nuclear magnetic resonance spectroscopy. Such analyses showed that the major VP4-derived glycan is a pentasaccharide comprising glucose, glucuronic acid, mannose, sulphated glucuronic acid and a terminal 5-N-formyl-legionaminic acid residue. This is the first observation of legionaminic acid, a sialic acid-like sugar, in an archaeal-derived glycan structure. The importance of this residue for viral infection was demonstrated upon incubation with N-acetylneuraminic acid, a similar monosaccharide. Such treatment reduced progeny virus production by half 4 h post infection. LC-ESI/MS analysis confirmed the presence of pentasaccharide precursors on two different VP4-derived peptides bearing the N-glycosylation signal, NTT. The same sites modified by the native host, Halorubrum sp. strain PV6, were also recognized by the Haloferax volcanii N-glycosylation apparatus, as determined by LC-ESI/MS of heterologously expressed VP4. Here, however, the N-linked pentasaccharide was the same as shown to decorate the S-layer glycoprotein in this species. Hence, N-glycosylation of the haloarchaeal viral protein, VP4, is host-specific. These results thus present additional examples of archaeal N-glycosylation diversity and show the ability of Archaea to modify heterologously expressed proteins.
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Affiliation(s)
- Lina Kandiba
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva 84105, Israel
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372
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Characterization of the viral O-glycopeptidome: a novel tool of relevance for vaccine design and serodiagnosis. J Virol 2012; 86:6268-78. [PMID: 22491453 DOI: 10.1128/jvi.00392-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Viral envelope proteins mediate interactions with host cells, leading to internalization and intracellular propagation. Envelope proteins are glycosylated and are known to serve important functions in masking host immunity to viral glycoproteins. However, the viral infectious cycle in cells may also lead to aberrant glycosylation that may elicit immunity. Our knowledge of immunity to aberrant viral glycans and glycoproteins is limited, potentially due to technical limitations in identifying immunogenic glycans and glycopeptide epitopes. This work describes three different complementary methods for high-throughput screening and identification of potential immunodominant O-glycopeptide epitopes on viral envelope glycoproteins: (i) on-chip enzymatic glycosylation of scan peptides, (ii) chemical glycopeptide microarray synthesis, and (iii) a one-bead-one-compound random glycopeptide library. We used herpes simplex virus type 2 (HSV-2) as a model system and identified a simple O-glycopeptide pan-epitope, (501)PPA(GalNAc)TAPG(507), on the mature gG-2 glycoprotein that was broadly recognized by IgG antibodies in HSV-2-infected individuals but not in HSV-1-infected or noninfected individuals. Serum reactivity to the extended sialyl-T glycoform was tolerated, suggesting that self glycans can participate in immune responses. The methods presented provide new insight into viral immunity and new targets for immunodiagnostic and therapeutic measures.
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373
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Delisle B, Gagnon CA, Lambert MÈ, D'Allaire S. Porcine reproductive and respiratory syndrome virus diversity of Eastern Canada swine herds in a large sequence dataset reveals two hypervariable regions under positive selection. INFECTION GENETICS AND EVOLUTION 2012; 12:1111-9. [PMID: 22484762 DOI: 10.1016/j.meegid.2012.03.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 03/13/2012] [Accepted: 03/18/2012] [Indexed: 12/12/2022]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is known to be genetically highly variable, but knowledge of sequence diversity from Eastern Canada and its degree of genetic plasticity in or near the principal neutralizing epitope (PNE) in association with evolutionary selective pressure is limited. The purposes of our study were to investigate the extent of strain diversity, the existing glycotypes and the amino acid sites under selective evolutionary pressure in its encoded protein, GP5, for a dataset of 1301 sequences (1998-2009). This was addressed by partitioning and clustering into subgenotypes a large number of open reading frame 5 sequences from the province of Quebec and analyzing the content of these subgenotypes. The overall pairwise diversity was 12% and was comparable to what has been reported around the world. The mean diversity for sequences within subgenotypes was around 7%. No marked variations in subgenotype emergence could be observed through time. Thirty-eight GP5 glycotype patterns were observed which included a newly identified site at position N57 which was already present in 1998. These patterns possessed one to six N-glycosylation sites in total and could be located in eight different positions. No obvious grouping of glycotypes could be established in relation to subgenotypes. Positions N44 and N51 were confirmed to be fixed N-glycosylation positions, whereas other positions where found to be shifting and located in or near hypervariable regions (HVRs) 1 and 2. Both HVRs were under selective evolutionary pressure in half of all subgenotypes including vaccine-like groups. Conversely, the PNE flanked by both HVRs was well conserved among most subgenotypes demonstrating potential molecular constraint in a probable viral binding region. The analysis of this dataset increased knowledge of evolutionary change inferred from genetic data, more specifically regarding the implications of both HVRs in PRRSV diversity.
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Affiliation(s)
- Benjamin Delisle
- Faculté de Médecine Vétérinaire, Université de Montréal, C.P. 5000, St-Hyacinthe, Québec, Canada J2S 7C6.
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374
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Dengue virus entry as target for antiviral therapy. J Trop Med 2012; 2012:628475. [PMID: 22529868 PMCID: PMC3317058 DOI: 10.1155/2012/628475] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 11/10/2011] [Indexed: 11/18/2022] Open
Abstract
Dengue virus (DENV) infections are expanding worldwide and, because of the lack of a vaccine, the search for antiviral products is imperative. Four serotypes of DENV are described and they all cause a similar disease outcome. It would be interesting to develop an antiviral product that can interact with all four serotypes, prevent host cell infection and subsequent immune activation. DENV entry is thus an interesting target for antiviral therapy. DENV enters the host cell through receptor-mediated endocytosis. Several cellular receptors have been proposed, and DC-SIGN, present on dendritic cells, is considered as the most important DENV receptor until now. Because DENV entry is a target for antiviral therapy, various classes of compounds have been investigated to inhibit this process. In this paper, an overview is given of all the putative DENV receptors, and the most promising DENV entry inhibitors are discussed.
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375
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Sun S, Wang Q, Zhao F, Chen W, Li Z. Prediction of biological functions on glycosylation site migrations in human influenza H1N1 viruses. PLoS One 2012; 7:e32119. [PMID: 22355413 PMCID: PMC3280219 DOI: 10.1371/journal.pone.0032119] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 01/19/2012] [Indexed: 12/28/2022] Open
Abstract
Protein glycosylation alteration is typically employed by various viruses for escaping immune pressures from their hosts. Our previous work had shown that not only the increase of glycosylation sites (glycosites) numbers, but also glycosite migration might be involved in the evolution of human seasonal influenza H1N1 viruses. More importantly, glycosite migration was likely a more effectively alteration way for the host adaption of human influenza H1N1 viruses. In this study, we provided more bioinformatics and statistic evidences for further predicting the significant biological functions of glycosite migration in the host adaptation of human influenza H1N1 viruses, by employing homology modeling and in silico protein glycosylation of representative HA and NA proteins as well as amino acid variability analysis at antigenic sites of HA and NA. The results showed that glycosite migrations in human influenza viruses have at least five possible functions: to more effectively mask the antigenic sites, to more effectively protect the enzymatic cleavage sites of neuraminidase (NA), to stabilize the polymeric structures, to regulate the receptor binding and catalytic activities and to balance the binding activity of hemagglutinin (HA) with the release activity of NA. The information here can provide some constructive suggestions for the function research related to protein glycosylation of influenza viruses, although these predictions still need to be supported by experimental data.
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Affiliation(s)
- Shisheng Sun
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Qinzhe Wang
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Fei Zhao
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Wentian Chen
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Zheng Li
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
- * E-mail:
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376
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Ito Y, Takeda Y. Analysis of glycoprotein processing in the endoplasmic reticulum using synthetic oligosaccharides. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2012; 88:31-40. [PMID: 22314014 PMCID: PMC3316936 DOI: 10.2183/pjab.88.31] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 12/19/2011] [Indexed: 05/31/2023]
Abstract
Protein quality control (QC) in the endoplasmic reticulum (ER) comprises many steps, including folding and transport of nascent proteins as well as degradation of misfolded proteins. Recent studies have revealed that high-mannose-type glycans play a pivotal role in the QC process. To gain knowledge about the molecular basis of this process with well-defined homogeneous compounds, we achieved a convergent synthesis of high-mannose-type glycans and their functionalized derivatives. We focused on analyses of UDP-Glc: glycoprotein glucosyltransferase (UGGT) and ER Glucosidase II, which play crucial roles in glycoprotein QC; however, their specificities remain unclear. In addition, we established an in vitro assay system mimicking the in vivo condition which is highly crowded because of the presence of various biomacromolecules.
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377
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Dortmans JCFM, Koch G, Rottier PJM, Peeters BPH. Virulence of Newcastle disease virus: what is known so far? Vet Res 2011; 42:122. [PMID: 22195547 PMCID: PMC3269386 DOI: 10.1186/1297-9716-42-122] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/23/2011] [Indexed: 12/22/2022] Open
Abstract
In the last decade many studies have been performed on the virulence of Newcastle disease virus (NDV). This is mainly due to the development of reverse genetics systems which made it possible to genetically modify NDV and to investigate the contribution of individual genes and genome regions to its virulence. However, the available information is scattered and a comprehensive overview of the factors and conditions determining NDV virulence is lacking. This review summarises, compares and discusses the available literature and shows that virulence of NDV is a complex trait determined by multiple genetic factors.
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Affiliation(s)
- Jos C F M Dortmans
- Central Veterinary Institute of Wageningen UR, PO Box 65, 8200 AB Lelystad, The Netherlands.
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378
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Colgrave ML, Snelling HJ, Shiell BJ, Feng YR, Chan YP, Bossart KN, Xu K, Nikolov DB, Broder CC, Michalski WP. Site occupancy and glycan compositional analysis of two soluble recombinant forms of the attachment glycoprotein of Hendra virus. Glycobiology 2011; 22:572-84. [PMID: 22171062 DOI: 10.1093/glycob/cwr180] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hendra virus (HeV) continues to cause morbidity and mortality in both humans and horses with a number of sporadic outbreaks. HeV has two structural membrane glycoproteins that mediate the infection of host cells: the attachment (G) and the fusion (F) glycoproteins that are essential for receptor binding and virion-host cell membrane fusion, respectively. N-linked glycosylation of viral envelope proteins are critical post-translation modifications that have been implicated in roles of structural integrity, virus replication and evasion of the host immune response. Deciphering the glycan composition and structure on these glycoproteins may assist in the development of glycan-targeted therapeutic intervention strategies. We examined the site occupancy and glycan composition of recombinant soluble G (sG) glycoproteins expressed in two different mammalian cell systems, transient human embryonic kidney 293 (HEK293) cells and vaccinia virus (VV)-HeLa cells, using a suite of biochemical and biophysical tools: electrophoresis, lectin binding and tandem mass spectrometry. The N-linked glycans of both VV and HEK293-derived sG glycoproteins carried predominantly mono- and disialylated complex-type N-glycans and a smaller population of high mannose-type glycans. All seven consensus sequences for N-linked glycosylation were definitively found to be occupied in the VV-derived protein, whereas only four sites were found and characterized in the HEK293-derived protein. We also report, for the first time, the existence of O-linked glycosylation sites in both proteins. The striking characteristic of both proteins was glycan heterogeneity in both N- and O-linked sites. The structural features of G protein glycosylation were also determined by X-ray crystallography and interactions with the ephrin-B2 receptor are discussed.
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Affiliation(s)
- Michelle L Colgrave
- Queensland Bioscience Precinct, CSIRO Livestock Industries, St Lucia, QLD 4067, Australia
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379
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Chen JR, Ma C, Wong CH. Vaccine design of hemagglutinin glycoprotein against influenza. Trends Biotechnol 2011; 29:426-34. [PMID: 21640418 DOI: 10.1016/j.tibtech.2011.04.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 04/19/2011] [Accepted: 04/20/2011] [Indexed: 11/29/2022]
Abstract
Influenza viruses continue to cause annual epidemics and pose the threat of a deadly global pandemic. Vaccination has remained the best approach for prevention and control of influenza infection. However, current influenza vaccines are only effective against closely-matched circulating strains, and therefore must be updated and administered every year. In this review, we discuss recent developments in the search for better influenza vaccines, especially using the major virus surface glycoprotein hemagglutinins (HAs). Understanding how glycans on HAs affect the immune response and knowledge of how broadly neutralizing antibodies are induced will pave the way for a cross-protective influenza vaccine that does not require frequent updates or annual immunizations.
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Affiliation(s)
- Juine-Ruey Chen
- Genomics Research Center, Academia Sinica, 128 Academia Road Section 2, Taipei 115, Taiwan
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380
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Helle F, Duverlie G, Dubuisson J. The hepatitis C virus glycan shield and evasion of the humoral immune response. Viruses 2011; 3:1909-32. [PMID: 22069522 PMCID: PMC3205388 DOI: 10.3390/v3101909] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 09/28/2011] [Accepted: 10/01/2011] [Indexed: 12/14/2022] Open
Abstract
Despite the induction of effective immune responses, 80% of hepatitis C virus (HCV)-infected individuals progress from acute to chronic hepatitis. In contrast to the cellular immune response, the role of the humoral immune response in HCV clearance is still subject to debate. Indeed, HCV escapes neutralizing antibodies in chronically infected patients and reinfection has been described in human and chimpanzee. Studies of antibody-mediated HCV neutralization have long been hampered by the lack of cell-culture-derived virus and the absence of a small animal model. However, the development of surrogate models and recent progress in HCV propagation in vitro now enable robust neutralization assays to be performed. These advances are beginning to shed some light on the mechanisms of HCV neutralization. This review summarizes the current state of knowledge of the viral targets of anti-HCV-neutralizing antibodies and the mechanisms that enable HCV to evade the humoral immune response. The recent description of the HCV glycan shield that reduces the immunogenicity of envelope proteins and masks conserved neutralizing epitopes at their surface constitutes the major focus of this review.
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Affiliation(s)
- François Helle
- Laboratory of Virology, EA4294, Jules Verne University of Picardie, Amiens 80000, France; E-Mail:
| | - Gilles Duverlie
- Laboratory of Virology, EA4294, Jules Verne University of Picardie, Amiens 80000, France; E-Mail:
- Virology Department, Amiens University Hospital Center, South Hospital, Amiens 80000, France
| | - Jean Dubuisson
- Inserm U1019, CNRS UMR8204, Center for Infection and Immunity of Lille (CIIL), Institut Pasteur de Lille, Université Lille Nord de France, Lille 59021, France; E-Mail:
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381
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Mahalingam A, Geonnotti AR, Balzarini J, Kiser PF. Activity and safety of synthetic lectins based on benzoboroxole-functionalized polymers for inhibition of HIV entry. Mol Pharm 2011; 8:2465-75. [PMID: 21879735 DOI: 10.1021/mp2002957] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Lectins derived from plant and microbial sources constitute a vital class of entry inhibitors that target the oligomannose residues on the HIV envelope gp120. Despite their potency and specificity, success of lectin-based entry inhibitors may be impeded by high manufacturing costs, formulation and potential mitogenicity. Therefore, there exists a gap in the HIV microbicides pipeline that underscores the need for mass producible, synthetic, broad-spectrum, and biocomptabile inhibitors of HIV entry. Here, we present the development of a polymeric synthetic lectin, based on benzoboroxole (BzB), which exhibits weak affinity (∼25 M(-1)) for nonreducing sugars, similar to those found on the HIV envelope. High molecular weight BzB-functionalized polymers demonstrated antiviral activity that increased with an increase in ligand density and molecular weight of the polymer construct, revealing that polyvalency improves activity. Polymers showed significant increase in activity from 25 to 75 mol % BzB functionalization with EC(50) of 15 μM and 15 nM, respectively. A further increase in mole functionalization to 90% resulted in an increase of the EC(50) (59 ± 5 nM). An increase in molecular weight of the polymer at 50 mol % BzB functionalization showed a gradual but significant increase in antiviral activity, with the highest activity seen with the 382 kDa polymer (EC(50) of 1.1 ± 0.5 nM in CEM cells and 11 ± 3 nM in TZM-bl cells). Supplementing the polymer backbone with 10 mol % sulfonic acid not only increased the aqueous solubility of the polymers by at least 50-fold but also demonstrated a synergistic increase in anti-HIV activity (4.0 ± 1.5 nM in TZM-bl cells), possibly due to electrostatic interactions between the negatively charged polymer backbone and the positively charged V3-loop in the gp120. The benzoboroxole-sulfonic acid copolymers showed no decrease in activity in the presence of a seminal concentration of fructose (p > 0.05). Additionally, the copolymers exhibit minimal, if any, effect on the cellular viability, barrier properties, or cytokine levels in human reconstructed ectocervical tissue after 3 days of repeated exposure and did not show pronounced activity against a variety of other RNA and DNA viruses.
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Affiliation(s)
- Alamelu Mahalingam
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112-5820, United States
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382
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Burland PA, Osborn HM, Turkson A. Synthesis and glycosidase inhibitory profiles of functionalised morpholines and oxazepanes. Bioorg Med Chem 2011; 19:5679-92. [DOI: 10.1016/j.bmc.2011.07.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 07/06/2011] [Accepted: 07/10/2011] [Indexed: 12/12/2022]
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383
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Uetrecht C, Heck AJR. Modern biomolecular mass spectrometry and its role in studying virus structure, dynamics, and assembly. Angew Chem Int Ed Engl 2011; 50:8248-62. [PMID: 21793131 PMCID: PMC7159578 DOI: 10.1002/anie.201008120] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Indexed: 01/04/2023]
Abstract
Over a century since its development, the analytical technique of mass spectrometry is blooming more than ever, and applied in nearly all aspects of the natural and life sciences. In the last two decades mass spectrometry has also become amenable to the analysis of proteins and even intact protein complexes, and thus begun to make a significant impact in the field of structural biology. In this Review, we describe the emerging role of mass spectrometry, with its different technical facets, in structural biology, focusing especially on structural virology. We describe how mass spectrometry has evolved into a tool that can provide unique structural and functional information about viral-protein and protein-complex structure, conformation, assembly, and topology, extending to the direct analysis of intact virus capsids of several million Dalton in mass. Mass spectrometry is now used to address important questions in virology ranging from how viruses assemble to how they interact with their host.
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Affiliation(s)
- Charlotte Uetrecht
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584 CH Utrecht (The Netherlands)
- Netherlands Proteomics Centre (The Netherlands)
- Present address: Molecular Biophysics, Uppsala University, Uppsala (Sweden)
| | - Albert J. R. Heck
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584 CH Utrecht (The Netherlands)
- Netherlands Proteomics Centre (The Netherlands)
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384
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Jaffee MB, Imperiali B. Exploiting topological constraints to reveal buried sequence motifs in the membrane-bound N-linked oligosaccharyl transferases. Biochemistry 2011; 50:7557-67. [PMID: 21812456 DOI: 10.1021/bi201018d] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The central enzyme in N-linked glycosylation is the oligosaccharyl transferase (OTase), which catalyzes glycan transfer from a polyprenyldiphosphate-linked carrier to select asparagines within acceptor proteins. PglB from Campylobacter jejuni is a single-subunit OTase with homology to the Stt3 subunit of the complex multimeric yeast OTase. Sequence identity between PglB and Stt3 is low (17.9%); however, both have a similar predicted architecture and contain the conserved WWDxG motif. To investigate the relationship between PglB and other Stt3 proteins, sequence analysis was performed using 28 homologues from evolutionarily distant organisms. Since detection of small conserved motifs within large membrane-associated proteins is complicated by divergent sequences surrounding the motifs, we developed a program to parse sequences according to predicted topology and then analyze topologically related regions. This approach identified three conserved motifs that served as the basis for subsequent mutagenesis and functional studies. This work reveals that several inter-transmembrane loop regions of PglB/Stt3 contain strictly conserved motifs that are essential for PglB function. The recent publication of a 3.4 Å resolution structure of full-length C. lari OTase provides clear structural evidence that these loops play a fundamental role in catalysis [ Lizak , C. ; ( 2011 ) Nature 474 , 350 - 355 ]. The current study provides biochemical support for the role of the inter-transmembrane domain loops in OTase catalysis and demonstrates the utility of combining topology prediction and sequence analysis for exposing buried pockets of homology in large membrane proteins. The described approach allowed detection of the catalytic motifs prior to availability of structural data and reveals additional catalytically relevant residues that are not predicted by structural data alone.
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Affiliation(s)
- Marcie B Jaffee
- Departments of Biology and Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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385
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Morelli L, Poletti L, Lay L. Carbohydrates and Immunology: Synthetic Oligosaccharide Antigens for Vaccine Formulation. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100296] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Laura Morelli
- Dipartimento di Chimica Organica e Industriale, CISI and ISTM‐CNR, Università degli Studi di Milano, Via Venezian 21, 20133 Milano, Italy
| | - Laura Poletti
- Dipartimento di Chimica Organica e Industriale, CISI and ISTM‐CNR, Università degli Studi di Milano, Via Venezian 21, 20133 Milano, Italy
| | - Luigi Lay
- Dipartimento di Chimica Organica e Industriale, CISI and ISTM‐CNR, Università degli Studi di Milano, Via Venezian 21, 20133 Milano, Italy
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386
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Sun S, Wang Q, Zhao F, Chen W, Li Z. Glycosylation site alteration in the evolution of influenza A (H1N1) viruses. PLoS One 2011; 6:e22844. [PMID: 21829533 PMCID: PMC3145772 DOI: 10.1371/journal.pone.0022844] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 07/01/2011] [Indexed: 12/24/2022] Open
Abstract
Influenza virus typically alters protein glycosylation in order to escape immune pressure from hosts and hence to facilitate survival in different host environments. In this study, the patterns and conservation of glycosylation sites on HA and NA of influenza A/H1N1 viruses isolated from various hosts at different time periods were systematically analyzed, by employing a new strategy combining genome-based glycosylation site prediction and 3D modeling of glycoprotein structures, for elucidation of the modes and laws of glycosylation site alteration in the evolution of influenza A/H1N1 viruses. The results showed that influenza H1N1 viruses underwent different alterations of protein glycosylation in different hosts. Two alternative modes of glycosylation site alteration were involved in the evolution of human influenza virus: One was an increase in glycosylation site numbers, which mainly occurred with high frequency in the early stages of evolution. The other was a change in the positional conversion of the glycosylation sites, which was the dominating mode with relatively low frequency in the later evolutionary stages. The mechanisms and possibly biological functions of glycosylation site alteration for the evolution of influenza A/H1N1 viruses were also discussed. Importantly, the significant role of positional alteration of glycosylation sites in the host adaptation of influenza virus was elucidated. Although the results still need to be supported by experimental data, the information here may provide some constructive suggestions for research into the glycosylation of influenza viruses as well as even the design of surveillance and the production of viral vaccines.
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Affiliation(s)
- Shisheng Sun
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
| | - Qinzhe Wang
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
| | - Fei Zhao
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
| | - Wentian Chen
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
| | - Zheng Li
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
- * E-mail:
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387
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Designed oligomers of cyanovirin-N show enhanced HIV neutralization. Proc Natl Acad Sci U S A 2011; 108:14079-84. [PMID: 21799112 DOI: 10.1073/pnas.1108777108] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cyanovirin-N (CV-N) is a small, cyanobacterial lectin that neutralizes many enveloped viruses, including human immunodeficiency virus type I (HIV-1). This antiviral activity is attributed to two homologous carbohydrate binding sites that specifically bind high mannose glycosylation present on envelope glycoproteins such as HIV-1 gp120. We created obligate CV-N oligomers to determine whether increasing the number of binding sites has an effect on viral neutralization. A tandem repeat of two CV-N molecules (CVN(2)) increased HIV-1 neutralization activity by up to 18-fold compared to wild-type CV-N. In addition, the CVN(2) variants showed extensive cross-clade reactivity and were often more potent than broadly neutralizing anti-HIV antibodies. The improvement in activity and broad cross-strain HIV neutralization exhibited by these molecules holds promise for the future therapeutic utility of these and other engineered CV-N variants.
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388
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Uetrecht C, Heck AJR. Moderne biomolekulare Massenspektrometrie und ihre Bedeutung für die Erforschung der Struktur, der Dynamik und des Aufbaus von Viren. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201008120] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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389
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Epidemiology and evolutionary characteristics of the porcine reproductive and respiratory syndrome virus in China between 2006 and 2010. J Clin Microbiol 2011; 49:3175-83. [PMID: 21775536 DOI: 10.1128/jcm.00234-11] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In 2006, an emerging highly pathogenic strain of porcine reproductive and respiratory syndrome virus (PRRSV), which causes continuous high fever and a high proportion of deaths in vaccinated pigs of all ages, broke out in mainland China and spread rapidly to neighboring countries. To examine the epidemiology and evolutionary characteristics of Chinese PRRSV after the 2006 outbreak, we tested 2,981 clinical samples collected from 2006 to 2010 in China, determined 153 Nsp2 sequences and 249 ORF5 sequences, and analyzed the epidemiology and genetic diversity of Chinese PRRSV. Our results showed that the percentage of PRRSV-positive specimens collected from sick pigs averaged 60.85% in the past 5 years and that the highly pathogenic PRRSV has become the dominant strain in China. Furthermore, a reemerging strain which apparently evolved from the highly pathogenic PRRSV strain in 2006 appeared to be widely prevalent in China from 2009 onwards. Sequence analyses revealed that the hypervariable region of Nsp2 in most of the isolates contained a discontinuous deletion equivalent to 30 amino acids, along with other types of deletions. Extensive amino acid substitutions in the GP5 sequence translated from ORF5 were found, particularly in the potential neutralization epitope and the N-glycosylation sites. Our results suggest that Chinese PRRSV has undergone rapid evolution and can circumvent immune responses induced by currently used vaccines. Information from this study will help in understanding the evolutionary characteristics of Chinese PRRSV and assist ongoing efforts to develop and use PRRSV vaccines in the future.
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390
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Lebarbenchon C, Stallknecht DE. Host shifts and molecular evolution of H7 avian influenza virus hemagglutinin. Virol J 2011; 8:328. [PMID: 21711553 PMCID: PMC3141685 DOI: 10.1186/1743-422x-8-328] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 06/28/2011] [Indexed: 11/22/2022] Open
Abstract
Evolutionary consequences of host shifts represent a challenge to identify the mechanisms involved in the emergence of influenza A (IA) viruses. In this study we focused on the evolutionary history of H7 IA virus in wild and domestic birds, with a particular emphasis on host shifts consequences on the molecular evolution of the hemagglutinin (HA) gene. Based on a dataset of 414 HA nucleotide sequences, we performed an extensive phylogeographic analysis in order to identify the overall genetic structure of H7 IA viruses. We then identified host shift events and investigated viral population dynamics in wild and domestic birds, independently. Finally, we estimated changes in nucleotide substitution rates and tested for positive selection in the HA gene. A strong association between the geographic origin and the genetic structure was observed, with four main clades including viruses isolated in North America, South America, Australia and Eurasia-Africa. We identified ten potential events of virus introduction from wild to domestic birds, but little evidence for spillover of viruses from poultry to wild waterbirds. Several sites involved in host specificity (addition of a glycosylation site in the receptor binding domain) and virulence (insertion of amino acids in the cleavage site) were found to be positively selected in HA nucleotide sequences, in genetically unrelated lineages, suggesting parallel evolution for the HA gene of IA viruses in domestic birds. These results highlight that evolutionary consequences of bird host shifts would need to be further studied to understand the ecological and molecular mechanisms involved in the emergence of domestic bird-adapted viruses.
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Affiliation(s)
- Camille Lebarbenchon
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602, USA.
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391
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Larkin A, Imperiali B. The expanding horizons of asparagine-linked glycosylation. Biochemistry 2011; 50:4411-26. [PMID: 21506607 DOI: 10.1021/bi200346n] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Asparagine-linked glycosylation involves the sequential assembly of an oligosaccharide onto a polyisoprenyl donor, followed by the en bloc transfer of the glycan to particular asparagine residues within acceptor proteins. These N-linked glycans play a critical role in a wide variety of biological processes, such as protein folding, cellular targeting and motility, and the immune response. In the past decade, research in the field of N-linked glycosylation has achieved major advances, including the discovery of new carbohydrate modifications, the biochemical characterization of the enzymes involved in glycan assembly, and the determination of the biological impact of these glycans on target proteins. It is now firmly established that this enzyme-catalyzed modification occurs in all three domains of life. However, despite similarities in the overall logic of N-linked glycoprotein biosynthesis among the three kingdoms, the structures of the appended glycans are markedly different and thus influence the functions of elaborated proteins in various ways. Though nearly all eukaryotes produce the same nascent tetradecasaccharide (Glc(3)Man(9)GlcNAc(2)), heterogeneity is introduced into this glycan structure after it is transferred to the protein through a complex series of glycosyl trimming and addition steps. In contrast, bacteria and archaea display diversity within their N-linked glycan structures through the use of unique monosaccharide building blocks during the assembly process. In this review, recent progress toward gaining a deeper biochemical understanding of this modification across all three kingdoms will be summarized. In addition, a brief overview of the role of N-linked glycosylation in viruses will also be presented.
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Affiliation(s)
- Angelyn Larkin
- Department of Chemistry Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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392
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Li W, Shi W, Qiao H, Ho SYW, Luo A, Zhang Y, Zhu C. Positive selection on hemagglutinin and neuraminidase genes of H1N1 influenza viruses. Virol J 2011; 8:183. [PMID: 21507270 PMCID: PMC3094300 DOI: 10.1186/1743-422x-8-183] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 04/21/2011] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Since its emergence in March 2009, the pandemic 2009 H1N1 influenza A virus has posed a serious threat to public health. To trace the evolutionary path of these new pathogens, we performed a selection-pressure analysis of a large number of hemagglutinin (HA) and neuraminidase (NA) gene sequences of H1N1 influenza viruses from different hosts. RESULTS Phylogenetic analysis revealed that both HA and NA genes have evolved into five distinct clusters, with further analyses indicating that the pandemic 2009 strains have experienced the strongest positive selection. We also found evidence of strong selection acting on the seasonal human H1N1 isolates. However, swine viruses from North America and Eurasia were under weak positive selection, while there was no significant evidence of positive selection acting on the avian isolates. A site-by-site analysis revealed that the positively selected sites were located in both of the cleaved products of HA (HA1 and HA2), as well as NA. In addition, the pandemic 2009 strains were subject to differential selection pressures compared to seasonal human, North American swine and Eurasian swine H1N1 viruses. CONCLUSIONS Most of these positively and/or differentially selected sites were situated in the B-cell and/or T-cell antigenic regions, suggesting that selection at these sites might be responsible for the antigenic variation of the viruses. Moreover, some sites were also associated with glycosylation and receptor-binding ability. Thus, selection at these positions might have helped the pandemic 2009 H1N1 viruses to adapt to the new hosts after they were introduced from pigs to humans. Positive selection on position 274 of NA protein, associated with drug resistance, might account for the prevalence of drug-resistant variants of seasonal human H1N1 influenza viruses, but there was no evidence that positive selection was responsible for the spread of the drug resistance of the pandemic H1N1 strains.
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Affiliation(s)
- Wenfu Li
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weifeng Shi
- UCD Conway Institute of Biomolecular and Biomedical Sciences, University College Dublin, Dublin 4, Ireland
| | - Huijie Qiao
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Simon YW Ho
- School of Biological Sciences, University of Sydney, Sydney NSW 2006, Australia
| | - Arong Luo
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanzhou Zhang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Chaodong Zhu
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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393
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Gu M, Liu W, Xu L, Cao Y, Yao C, Hu S, Liu X. Positive selection in the hemagglutinin-neuraminidase gene of Newcastle disease virus and its effect on vaccine efficacy. Virol J 2011; 8:150. [PMID: 21453506 PMCID: PMC3101160 DOI: 10.1186/1743-422x-8-150] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 03/31/2011] [Indexed: 12/24/2022] Open
Abstract
Background To investigate the relationship between the selective pressure and the sequence variation of the hemagglutinin-neuraminidase (HN) protein, we performed the positive selection analysis by estimating the ratio of non-synonymous to synonymous substitutions with 132 complete HN gene sequences of Newcastle disease viruses (NDVs) isolated in China. Results The PAML software applying a maximum likelihood method was used for the analysis and three sites (residues 266, 347 and 540) in the HN protein were identified as being under positive selection. Codon 347 was located exactly in a recognized antigenic determinant (residues 345-353) and codon 266 in a predicted linear B-cell epitope. Substitutions at codon 540 contributed to the N-linked glycosylation potential of residue 538. To further evaluate the effect of positively selected sites on the vaccine efficacy, we constructed two recombinant fowlpox viruses rFPV-JS6HN and rFPV-LaSHN, expressing the HN proteins from a genotype VII field isolate Go/JS6/05 (with A266, K347 and A540) and vaccine strain La Sota (with V266, E347 and T540), respectively. Two groups of SPF chickens, 18 each, were vaccinated with the two recombinant fowlpox viruses and challenged by Go/JS6/05 at 3 weeks post-immunization. The results showed that rFPV-JS6HN could elicit more effective immunity against the prevalent virus infection than rFPV-LaSHN in terms of reducing virus shedding. Conclusions The analysis of positively selected codons and their effect on the vaccine efficacy indicated that the selective pressure on the HN protein can induce antigenic variation, and new vaccine to control the current ND epidemics should be developed.
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Affiliation(s)
- Min Gu
- Animal Infectious Disease Laboratory, School of Veterinary Medicine, Yangzhou University, Yangzhou 225009, PR China
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394
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Michelow IC, Lear C, Scully C, Prugar LI, Longley CB, Yantosca LM, Ji X, Karpel M, Brudner M, Takahashi K, Spear GT, Ezekowitz RAB, Schmidt EV, Olinger GG. High-dose mannose-binding lectin therapy for Ebola virus infection. J Infect Dis 2011; 203:175-9. [PMID: 21288816 PMCID: PMC3071052 DOI: 10.1093/infdis/jiq025] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mannose-binding lectin (MBL) targets diverse microorganisms for phagocytosis and complement-mediated lysis by binding specific surface glycans. Although recombinant human MBL (rhMBL) trials have focused on reconstitution therapy, safety studies have identified no barriers to its use at higher levels. Ebola viruses cause fatal hemorrhagic fevers for which no treatment exists and that are feared as potential biothreat agents. We found that mice whose rhMBL serum concentrations were increased ≥7-fold above average human levels survived otherwise fatal Ebola virus infections and became immune to virus rechallenge. Because Ebola glycoproteins potentially model other glycosylated viruses, rhMBL may offer a novel broad-spectrum antiviral approach.
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Affiliation(s)
- Ian C Michelow
- Program of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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395
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Das PB, Vu HLX, Dinh PX, Cooney JL, Kwon B, Osorio FA, Pattnaik AK. Glycosylation of minor envelope glycoproteins of porcine reproductive and respiratory syndrome virus in infectious virus recovery, receptor interaction, and immune response. Virology 2011; 410:385-94. [PMID: 21195444 DOI: 10.1016/j.virol.2010.12.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 09/24/2010] [Accepted: 12/03/2010] [Indexed: 02/07/2023]
Abstract
The role of N-glycosylation of the three minor envelope glycoproteins (GP2, GP3, and GP4) of porcine reproductive and respiratory syndrome virus (PRRSV) on infectious virus production, interactions with the receptor CD163, and neutralizing antibody production in infected pigs was examined. By mutation of the glycosylation sites in these proteins, the studies show that glycan addition at N184 of GP2, N42, N50 and N131 of GP3 is necessary for infectious virus production. Although single-site mutants of GP4 led to infectious virus production, mutation of any two sites in GP4 was lethal. Furthermore, the glycosylation of GP2 and GP4 was important for efficient interaction with CD163. Unlike PRRSVs encoding hypoglycosylated form of GP5 that induced significantly higher levels of neutralizing antibodies in infected piglets, PRRSVs encoding hypoglycosylated forms of GP2, GP3 or GP4 did not. These studies reveal the importance of glycosylation of these minor GPs in the biology of PRRSV.
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Affiliation(s)
- Phani B Das
- School of Veterinary Medicine and Biomedical Sciences, and the Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0900, USA
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396
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Wang X, Wang S, Lin Y, Jiang C, Ma J, Zhao L, Lv X, Wang F, Shen R, Zhou J. Unique evolution characteristics of the envelope protein of EIAV(LN₄₀), a virulent strain of equine infectious anemia virus. Virus Genes 2011; 42:220-8. [PMID: 21369830 DOI: 10.1007/s11262-010-0563-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 12/20/2010] [Indexed: 11/30/2022]
Abstract
The Chinese equine infectious anemia virus (EIAV) virulent strain EIAV(LN40) is derived from a naturally occurring virus by continuously passing in horses for 16 generations. Its genome sequence is 23% different from that of the American strains or the Japanese strains, and the variation of envelope gp90 surface unit (SU) is as high as 41%. In this study, evolutions of the EIAV(LN40) gp90 gene in four infected horses were analyzed. Results showed that new quasispecies arose in the early stage of infection in all EIAV(LN40)-infected horses. These quasispecies belonged to branches different from EIAV(LN40) in a phylogenetic tree. In contrast, the gp90 sequences of viruses isolated after disease onset remained in the same phylogenetic branch as EIAV(LN40), with some having exactly the same sequences. The glycosylation sites 191NSSN and 237NNTW in the V3 and V4 region present or absent simultaneously in most of the predicted amino acid sequences. Changes in the glycosylation sites within V3, V4, and V5 regions are usually associated with the disease status. Glycosylation sites (191NSSN, 237NNTW, and 280NDTS) within these three regions were present in EIAV(LN40) and most of the quasispecies isolated after, but not before disease onset. These unique evolutionary characteristics of SU have not been reported for EIAV and other lentiviruses. Our results provide a reference for a further understanding of the mechanism underlying the persistent infection and escape from immune surveillance of EIAV.
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Affiliation(s)
- Xuefeng Wang
- Division of Large Animal Infectious Diseases, Stated key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
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397
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Choi KJ, Grass S, Paek S, St. Geme JW, Yeo HJ. The Actinobacillus pleuropneumoniae HMW1C-like glycosyltransferase mediates N-linked glycosylation of the Haemophilus influenzae HMW1 adhesin. PLoS One 2010; 5:e15888. [PMID: 21209858 PMCID: PMC3012730 DOI: 10.1371/journal.pone.0015888] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2010] [Accepted: 11/26/2010] [Indexed: 11/29/2022] Open
Abstract
The Haemophilus influenzae HMW1 adhesin is an important virulence exoprotein that is secreted via the two-partner secretion pathway and is glycosylated at multiple asparagine residues in consensus N-linked sequons. Unlike the heavily branched glycans found in eukaryotic N-linked glycoproteins, the modifying glycan structures in HMW1 are mono-hexoses or di-hexoses. Recent work demonstrated that the H. influenzae HMW1C protein is the glycosyltransferase responsible for transferring glucose and galactose to the acceptor sites of HMW1. An Actinobacillus pleuropneumoniae protein designated ApHMW1C shares high-level homology with HMW1C and has been assigned to the GT41 family, which otherwise contains only O-glycosyltransferases. In this study, we demonstrated that ApHMW1C has N-glycosyltransferase activity and is able to transfer glucose and galactose to known asparagine sites in HMW1. In addition, we found that ApHMW1C is able to complement a deficiency of HMW1C and mediate HMW1 glycosylation and adhesive activity in whole bacteria. Initial structure-function studies suggested that ApHMW1C consists of two domains, including a 15-kDa N-terminal domain and a 55-kDa C-terminal domain harboring glycosyltransferase activity. These findings suggest a new subfamily of HMW1C-like glycosyltransferases distinct from other GT41 family O-glycosyltransferases.
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Affiliation(s)
- Kyoung-Jae Choi
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Susan Grass
- Department of Pediatrics and Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Seonghee Paek
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Joseph W. St. Geme
- Department of Pediatrics and Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Hye-Jeong Yeo
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
- * E-mail:
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398
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Das SR, Puigbò P, Hensley SE, Hurt DE, Bennink JR, Yewdell JW. Glycosylation focuses sequence variation in the influenza A virus H1 hemagglutinin globular domain. PLoS Pathog 2010; 6:e1001211. [PMID: 21124818 PMCID: PMC2991263 DOI: 10.1371/journal.ppat.1001211] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 10/26/2010] [Indexed: 01/26/2023] Open
Abstract
Antigenic drift in the influenza A virus hemagglutinin (HA) is responsible for seasonal reformulation of influenza vaccines. Here, we address an important and largely overlooked issue in antigenic drift: how does the number and location of glycosylation sites affect HA evolution in man? We analyzed the glycosylation status of all full-length H1 subtype HA sequences available in the NCBI influenza database. We devised the "flow index" (FI), a simple algorithm that calculates the tendency for viruses to gain or lose consensus glycosylation sites. The FI predicts the predominance of glycosylation states among existing strains. Our analyses show that while the number of glycosylation sites in the HA globular domain does not influence the overall magnitude of variation in defined antigenic regions, variation focuses on those regions unshielded by glycosylation. This supports the conclusion that glycosylation generally shields HA from antibody-mediated neutralization, and implies that fitness costs in accommodating oligosaccharides limit virus escape via HA hyperglycosylation.
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Affiliation(s)
- Suman R. Das
- Laboratory of Viral Diseases, NIAID, Bethesda, Maryland, United States of America
| | - Pere Puigbò
- National Center for Biotechnology Information, Bethesda, Maryland, United States of America
| | - Scott E. Hensley
- Laboratory of Viral Diseases, NIAID, Bethesda, Maryland, United States of America
| | - Darrell E. Hurt
- Computational Biology Bioinformatics and Computational Biosciences Branch (BCBB), NIAID, Bethesda, Maryland, United States of America
| | - Jack R. Bennink
- Laboratory of Viral Diseases, NIAID, Bethesda, Maryland, United States of America
| | - Jonathan W. Yewdell
- Laboratory of Viral Diseases, NIAID, Bethesda, Maryland, United States of America
- * E-mail:
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399
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Soya N, Fang Y, Palcic MM, Klassen JS. Trapping and characterization of covalent intermediates of mutant retaining glycosyltransferases. Glycobiology 2010; 21:547-52. [PMID: 21098513 DOI: 10.1093/glycob/cwq190] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The enzymatic mechanism by which retaining glycosyltransferases (GTs) transfer monosaccharides with net retention of the anomeric configuration has, so far, resisted elucidation. Here, direct detection of covalent glycosyl-enzyme intermediates for mutants of two model retaining GTs, the human blood group synthesizing α-(1 → 3)-N-acetylgalactosaminyltransferase (GTA) and α-(1 → 3)-galactosyltransferase (GTB) mutants, by mass spectrometry (MS) is reported. Incubation of mutants of GTA or GTB, in which the putative catalytic nucleophile Glu(303) was replaced with Cys (i.e. GTA(E303C) and GTB(E303C)), with their respective donor substrate results in a covalent intermediate. Tandem MS analysis using collision-induced dissociation confirmed Cys(303) as the site of glycosylation. Exposure of the glycosyl-enzyme intermediates to a disaccharide acceptor results in the formation of the corresponding enzymatic trisaccharide products. These findings suggest that the GTA(E303C) and GTB(E303C) mutants may operate by a double-displacement mechanism.
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Affiliation(s)
- Naoto Soya
- Alberta Ingenuity Centre for Carbohydrate Science, Department of Chemistry, University of Alberta, Edmonton, Alta, Canada
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400
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The receptor-binding domain of influenza virus hemagglutinin produced in Escherichia coli folds into its native, immunogenic structure. J Virol 2010; 85:865-72. [PMID: 21068239 DOI: 10.1128/jvi.01412-10] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The hemagglutinin (HA) surface glycoprotein promotes influenza virus entry and is the key protective antigen in natural immunity and vaccines. The HA protein is a trimeric envelope glycoprotein consisting of a globular receptor-binding domain (HA-RBD) that is inserted into a membrane fusion-mediating stalk domain. Similar to other class I viral fusion proteins, the fusogenic stalk domain spontaneously refolds into its postfusion conformation when expressed in isolation, consistent with this domain being trapped in a metastable conformation. Using X-ray crystallography, we show that the influenza virus HA-RBD refolds spontaneously into its native, immunogenic structure even when expressed in an unglycosylated form in Escherichia coli. In the 2.10-Å structure of the HA-RBD, the receptor-binding pocket is intact and its conformational epitopes are preserved. Recombinant HA-RBD is immunogenic and protective in ferrets, and the protein also binds with specificity to sera from influenza virus-infected humans. Overall, the data provide a structural basis for the rapid production of influenza vaccines in E. coli. From an evolutionary standpoint, the ability of the HA-RBD to refold spontaneously into its native conformation suggests that influenza virus acquired this domain as an insertion into an ancestral membrane-fusion domain. The insertion of independently folding domains into fusogenic stalk domains may be a common feature of class I viral fusion proteins.
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