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Martín D, Calder LJ, García-Barreno B, Skehel JJ, Melero JA. Sequence elements of the fusion peptide of human respiratory syncytial virus fusion protein required for activity. J Gen Virol 2006; 87:1649-1658. [PMID: 16690930 DOI: 10.1099/vir.0.81715-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have reported previously the expression and purification of an anchorless form of the human respiratory syncytial virus (HRSV) F protein (F(TM-)) representing the ectodomain of the full-length F. F(TM-) molecules are seen as unaggregated cones by electron microscopy but completion of proteolytic cleavage of the F0 monomers in the F(TM-) trimer leads to a change in shape from cones to lollipops that aggregate into rosettes. This aggregation apparently occurs by interaction of the fusion peptides of F(TM-) molecules that are exposed after cleavage. Since exposure of the fusion peptide is a key event in the process of membrane fusion, changes associated with F(TM-) cleavage may reflect those occurring in full-length F during membrane fusion. Deletions or substitutions that changed either the length, charge or hydrophobicity of the fusion peptide inhibited aggregation of F(TM-), and these mutants remained as unaggregated cones after cleavage. In contrast, more conservative changes did not inhibit the change of shape and aggregation of F(TM-). When the same changes were introduced in the fusion peptide of full-length F, only the mutations that inhibited aggregation of F(TM-) prevented membrane fusion. Thus, the conformational changes that follow completion of cleavage of the F(TM-) protein require a functional fusion peptide. These sequence constraints may restrict accumulation of sequence changes in the fusion peptide of HRSV F when compared with other hydrophobic regions of the molecule.
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Affiliation(s)
- Diana Martín
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
| | - Lesley J Calder
- National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Blanca García-Barreno
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
| | - John J Skehel
- National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - José A Melero
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
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52
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Galdiero S, Vitiello M, D'Isanto M, Falanga A, Collins C, Raieta K, Pedone C, Browne H, Galdiero M. Analysis of synthetic peptides from heptad-repeat domains of herpes simplex virus type 1 glycoproteins H and B. J Gen Virol 2006; 87:1085-1097. [PMID: 16603508 DOI: 10.1099/vir.0.81794-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Human herpesviruses enter cells by fusion of their own membrane with a cellular membrane through the concerted action of multiple viral proteins and cellular receptors. Two conserved viral glycoproteins, gB and gH, are required for herpes simplex virus type 1 (HSV-1)-mediated membrane fusion, but little is known of how these proteins cooperate during entry. Both glycoproteins were shown to contain heptad repeat (HR) sequences predicted to form alpha-helical coiled coils, and the inhibitory activity against infection of four sets of synthetic peptides corresponding to HR1 and HR2 of gB and gH was tested. The interactions between these HR peptides were also investigated by circular dichroism, native polyacrylamide-gel electrophoresis and size exclusion high-performance liquid chromatography. gH coiled-coil peptides were more effective than gB coiled-coils peptides in inhibiting virus infectivity. The peptides did not impair fusion when added to cells immediately after infection. In contrast, inhibition of infection was observed, albeit to various extents, when peptides were added to virus before or during inoculation. The results of biophysical analyses were indicative of the existence of an interaction between HR1 and HR2 of gH and suggest that the HRs of gB and gH do not interact with each other.
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Affiliation(s)
- Stefania Galdiero
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Naples, Italy
- Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy
- Department of Biological Sciences, Division of Biostructures, University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy
| | - Mariateresa Vitiello
- Department of Experimental Medicine, II University of Naples, Via De Crecchio 7, 80138 Naples, Italy
- Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy
| | - Marina D'Isanto
- Department of Experimental Medicine, II University of Naples, Via De Crecchio 7, 80138 Naples, Italy
| | - Annarita Falanga
- Department of Experimental Medicine, II University of Naples, Via De Crecchio 7, 80138 Naples, Italy
| | - Craig Collins
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK
| | - Katia Raieta
- Department of Experimental Medicine, II University of Naples, Via De Crecchio 7, 80138 Naples, Italy
| | - Carlo Pedone
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Naples, Italy
- Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy
- Department of Biological Sciences, Division of Biostructures, University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy
| | - Helena Browne
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK
| | - Massimiliano Galdiero
- Department of Experimental Medicine, II University of Naples, Via De Crecchio 7, 80138 Naples, Italy
- Centro Interuniversitario di Ricerca sui Peptidi Bioattivi, University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy
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53
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McGinnes LW, Morrison TG. Inhibition of receptor binding stabilizes Newcastle disease virus HN and F protein-containing complexes. J Virol 2006; 80:2894-903. [PMID: 16501098 PMCID: PMC1395434 DOI: 10.1128/jvi.80.6.2894-2903.2006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Receptor binding of paramyxovirus attachment proteins and the interactions between attachment and fusion (F) proteins are thought to be central to activation of the F protein activity; however, mechanisms involved are unclear. To explore the relationships between Newcastle disease virus (NDV) HN and F protein interactions and HN protein attachment to sialic acid receptors, HN and F protein-containing complexes were detected and quantified by reciprocal coimmunoprecipitation from extracts of transfected avian cells. To inhibit HN protein receptor binding, cells transfected with HN and F protein cDNAs were incubated with neuraminidase from the start of transfection. Under these conditions, no fusion was observed, but amounts of HN and F protein complexes increased twofold over amounts detected in extracts of untreated cells. Stimulation of attachment by incubation of untransfected target cells with neuraminidase-treated HN and F protein-expressing cells resulted in a twofold decrease in amounts of HN and F protein complexes. In contrast, high levels of complexes containing HN protein and an uncleaved F protein (F-K115Q) were detected, and those levels were unaffected by neuraminidase treatment of cell monolayers or by incubation with target cells. These results suggest that HN and F proteins reside in a complex in the absence of receptor binding. Furthermore, the results show that not only receptor binding but also F protein cleavage are necessary for disassociation of the HN and F protein-containing complexes.
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Affiliation(s)
- L W McGinnes
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, 55 Lake Ave. North, Worcester, Massachusetts 01655, USA
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Bossart KN, Broder CC. Developments towards effective treatments for Nipah and Hendra virus infection. Expert Rev Anti Infect Ther 2006; 4:43-55. [PMID: 16441208 DOI: 10.1586/14787210.4.1.43] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Hendra and Nipah virus are closely related emerging viruses comprising the Henipavirus genus of the subfamily Paramyxovirinae and are distinguished by their ability to cause fatal disease in both animal and human hosts. In particular, the high mortality and person-to-person transmission associated with the most recent Nipah virus outbreaks, as well as the very recent re-emergence of Hendra virus, has confirmed the importance and necessity of developing effective therapeutic interventions. Much research conducted on the henipaviruses over the past several years has focused on virus entry, including the attachment of virus to the host cell, the identification of the virus receptor and the membrane fusion process between the viral and host cell membranes. These findings have led to the development of possible vaccine candidates, as well as potential antiviral therapeutics. The common link among all of the possible antiviral agents discussed here, which have also been developed and tested, is that they target very early stages of the infection process. The establishment and validation of suitable animal models of Henipavirus infection and pathogenesis are also discussed as they will be crucial in the assessment of the effectiveness of any treatments for Hendra and Nipah virus infection.
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Affiliation(s)
- Katharine N Bossart
- Australian Animal Health Laboratory, CSIRO Livestock Industries, Geelong, Victoria 3220, Australia.
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55
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Lamb RA, Paterson RG, Jardetzky TS. Paramyxovirus membrane fusion: lessons from the F and HN atomic structures. Virology 2006; 344:30-7. [PMID: 16364733 PMCID: PMC7172328 DOI: 10.1016/j.virol.2005.09.007] [Citation(s) in RCA: 187] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Accepted: 09/07/2005] [Indexed: 01/10/2023]
Abstract
Paramyxoviruses enter cells by fusion of their lipid envelope with the target cell plasma membrane. Fusion of the viral membrane with the plasma membrane allows entry of the viral genome into the cytoplasm. For paramyxoviruses, membrane fusion occurs at neutral pH, but the trigger mechanism that controls the viral entry machinery such that it occurs at the right time and in the right place remains to be elucidated. Two viral glycoproteins are key to the infection process—an attachment protein that varies among different paramyxoviruses and the fusion (F) protein, which is found in all paramyxoviruses. For many of the paramyxoviruses (parainfluenza viruses 1–5, mumps virus, Newcastle disease virus and others), the attachment protein is the hemagglutinin/neuraminidase (HN) protein. In the last 5 years, atomic structures of paramyxovirus F and HN proteins have been reported. The knowledge gained from these structures towards understanding the mechanism of viral membrane fusion is described.
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Affiliation(s)
- Robert A Lamb
- Howard Hughes Medical Institute, Northwestern University, Evanston, IL 60208-3500, USA.
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56
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Philipp-Staheli J, Marquardt T, Thouless ME, Bruce AG, Grant RF, Tsai CC, Rose TM. Genetic variability of the envelope gene of Type D simian retrovirus-2 (SRV-2) subtypes associated with SAIDS-related retroperitoneal fibromatosis in different macaque species. Virol J 2006; 3:11. [PMID: 16515713 PMCID: PMC1450265 DOI: 10.1186/1743-422x-3-11] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Accepted: 03/06/2006] [Indexed: 11/21/2022] Open
Abstract
Background D-type simian retrovirus-2 (SRV-2) causes an AIDS-like immune deficiency syndrome (SAIDS) in various macaque species. SAIDS is often accompanied by retroperitoneal fibromatosis (RF), an aggressive fibroproliferative disorder reminiscent of Kaposi's sarcoma in patients with HIV-induced AIDS. In order to determine the association of SRV-2 subtypes with SAIDS-RF, and study the evolution and transmission of SRV-2 in captive macaque populations, we have molecularly characterized the env gene of a number of SRV-2 isolates from different macaque species with and without RF. Results We sequenced the env gene from eighteen SRV-2 isolates and performed sequence comparisons and phylogenetic analyses. Our studies revealed the presence of six distinct subtypes of SRV-2, three of which were associated with SAIDS-RF cases. We found no association between SRV-2 subtypes and a particular macaque species. Little sequence variation was detected in SRV-2 isolates from the same individual, even after many years of infection, or from macaques housed together or related by descent from a common infected parent. Seventy-two amino acid changes were identified, most occurring in the larger gp70 surface protein subunit. In contrast to the lentiviruses, none of the amino acid variations involved potential N-linked glycosylation sites. Structural analysis of a domain within the gp22/gp20 transmembrane subunit that was 100% conserved between SRV-2 subtypes, revealed strong similarities to a disulfide-bonded loop that is crucial for virus-cell fusion and is found in retroviruses and filoviruses. Conclusion Our study suggests that separate introductions of at least six parental SRV-2 subtypes into the captive macaque populations in the U.S. have occurred with subsequent horizontal transfer between macaque species and primate centers. No specific association of a single SRV-2 subtype with SAIDS-RF was seen. The minimal genetic variability of the env gene within a subtype over time suggests that a strong degree of adaptation to its primate host has occurred during evolution of the virus.
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Affiliation(s)
- Jeannette Philipp-Staheli
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, USA
| | - Taya Marquardt
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, USA
| | - Margaret E Thouless
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, USA
| | | | - Richard F Grant
- Washington National Primate Research Center, University of Washington, Seattle, Washington, USA
| | - Che-Chung Tsai
- Washington National Primate Research Center, University of Washington, Seattle, Washington, USA
| | - Timothy M Rose
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, USA
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57
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Lip KM, Shen S, Yang X, Keng CT, Zhang A, Oh HLJ, Li ZH, Hwang LA, Chou CF, Fielding BC, Tan THP, Mayrhofer J, Falkner FG, Fu J, Lim SG, Hong W, Tan YJ. Monoclonal antibodies targeting the HR2 domain and the region immediately upstream of the HR2 of the S protein neutralize in vitro infection of severe acute respiratory syndrome coronavirus. J Virol 2006; 80:941-50. [PMID: 16378996 PMCID: PMC1346840 DOI: 10.1128/jvi.80.2.941-950.2006] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We have previously shown that an Escherichia coli-expressed, denatured spike (S) protein fragment of the severe acute respiratory coronavirus, containing residues 1029 to 1192 which include the heptad repeat 2 (HR2) domain, was able to induce neutralizing polyclonal antibodies (C. T. Keng, A. Zhang, S. Shen, K. M. Lip, B. C. Fielding, T. H. Tan, C. F. Chou, C. B. Loh, S. Wang, J. Fu, X. Yang, S. G. Lim, W. Hong, and Y. J. Tan, J. Virol. 79:3289-3296, 2005). In this study, monoclonal antibodies (MAbs) were raised against this fragment to identify the linear neutralizing epitopes in the functional domain and to investigate the mechanisms involved in neutralization. Eighteen hybridomas secreting the S protein-specific MAbs were obtained. Binding sites of these MAbs were mapped to four linear epitopes. Two of them were located within the HR2 region and two immediately upstream of the HR2 domain. MAbs targeting these epitopes showed in vitro neutralizing activities and were able to inhibit cell-cell membrane fusion. These results provide evidence of novel neutralizing epitopes that are located in the HR2 domain and the spacer region immediately upstream of the HR2 of the S protein.
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Affiliation(s)
- Kuo-Ming Lip
- Institute of Molecular and Cell Biology, Proteos, 61 Biopolis Drive, Singapore 138673
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58
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Yin HS, Wen X, Paterson RG, Lamb RA, Jardetzky TS. Structure of the parainfluenza virus 5 F protein in its metastable, prefusion conformation. Nature 2006; 439:38-44. [PMID: 16397490 PMCID: PMC7095149 DOI: 10.1038/nature04322] [Citation(s) in RCA: 339] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2005] [Accepted: 10/11/2005] [Indexed: 11/09/2022]
Abstract
Enveloped viruses have evolved complex glycoprotein machinery that drives the fusion of viral and cellular membranes, permitting entry of the viral genome into the cell. For the paramyxoviruses, the fusion (F) protein catalyses this membrane merger and entry step, and it has been postulated that the F protein undergoes complex refolding during this process. Here we report the crystal structure of the parainfluenza virus 5 F protein in its prefusion conformation, stabilized by the addition of a carboxy-terminal trimerization domain. The structure of the F protein shows that there are profound conformational differences between the pre- and postfusion states, involving transformations in secondary and tertiary structure. The positions and structural transitions of key parts of the fusion machinery, including the hydrophobic fusion peptide and two helical heptad repeat regions, clarify the mechanism of membrane fusion mediated by the F protein.
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Affiliation(s)
- Hsien-Sheng Yin
- Howard Hughes Medical Institute,
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500 USA
| | - Xiaolin Wen
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500 USA
| | - Reay G. Paterson
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500 USA
| | - Robert A. Lamb
- Howard Hughes Medical Institute,
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500 USA
| | - Theodore S. Jardetzky
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500 USA
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59
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Abstract
Hendra virus and Nipah virus are highly pathogenic paramyxoviruses that have recently emerged from flying foxes to cause serious disease outbreaks in humans and livestock in Australia, Malaysia, Singapore and Bangladesh. Their unique genetic constitution, high virulence and wide host range set them apart from other paramyxoviruses. These features led to their classification into the new genus Henipavirus within the family Paramyxoviridae and to their designation as Biosafety Level 4 pathogens. This review provides an overview of henipaviruses and the types of infection they cause, and describes how studies on the structure and function of henipavirus proteins expressed from cloned genes have provided insights into the unique biological properties of these emerging human pathogens.
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Affiliation(s)
- Bryan T Eaton
- Australian Animal Health Laboratory, Commonwealth Scientific and Industrial Research Organization, 5 Portarlington Road, Geelong, Victoria 3220, Australia.
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60
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Franke J, Batts WN, Ahne W, Kurath G, Winton JR. Sequence motifs and prokaryotic expression of the reptilian paramyxovirus fusion protein. Arch Virol 2005; 151:449-64. [PMID: 16328138 PMCID: PMC7086783 DOI: 10.1007/s00705-005-0663-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Accepted: 09/19/2005] [Indexed: 10/25/2022]
Abstract
Fourteen reptilian paramyxovirus isolates were chosen to represent the known extent of genetic diversity among this novel group of viruses. Selected regions of the fusion (F) gene were sequenced, analyzed and compared. The F gene of all isolates contained conserved motifs homologous to those described for other members of the family Paramyxoviridae including: signal peptide, transmembrane domain, furin cleavage site, fusion peptide, N-linked glycosylation sites, and two heptad repeats, the second of which (HRB-LZ) had the characteristics of a leucine zipper. Selected regions of the fusion gene of isolate Gono-GER85 were inserted into a prokaryotic expression system to generate three recombinant protein fragments of various sizes. The longest recombinant protein was cleaved by furin into two fragments of predicted length. Western blot analysis with virus-neutralizing rabbit-antiserum against this isolate demonstrated that only the longest construct reacted with the antiserum. This construct was unique in containing 30 additional C-terminal amino acids that included most of the HRB-LZ. These results indicate that the F genes of reptilian paramyxoviruses contain highly conserved motifs typical of other members of the family and suggest that the HRB-LZ domain of the reptilian paramyxovirus F protein contains a linear antigenic epitope.
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Affiliation(s)
- J Franke
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington 98115, USA
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61
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Veiga S, Yuan Y, Li X, Santos NC, Liu G, Castanho MA. Why are HIV-1 fusion inhibitors not effective against SARS-CoV? Biophysical evaluation of molecular interactions. Biochim Biophys Acta Gen Subj 2005; 1760:55-61. [PMID: 16290276 PMCID: PMC7116955 DOI: 10.1016/j.bbagen.2005.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Revised: 09/20/2005] [Accepted: 10/06/2005] [Indexed: 11/20/2022]
Abstract
The envelope spike (S) glycoprotein of the severe acute respiratory syndrome associated coronavirus (SARS-CoV) mediates the entry of the virus into target cells. Recent studies point out to a cell entry mechanism of this virus similar to other enveloped viruses, such as HIV-1. As it happens with other viruses peptidic fusion inhibitors, SARS-CoV S protein HR2-derived peptides are potential therapeutic drugs against the virus. It is believed that HR2 peptides block the six-helix bundle formation, a key structure in the viral fusion, by interacting with the HR1 region. It is a matter of discussion if the HIV-1 gp41 HR2-derived peptide T20 (enfuvirtide) could be a possible SARS-CoV inhibitor given the similarities between the two viruses. We tested the possibility of interaction between both T20 (HIV-1 gp41 HR2-derived peptide) and T-1249 with S protein HR1- and HR2-derived peptides. Our biophysical data show a significant interaction between a SARS-CoV HR1-derived peptide and T20. However, the interaction is only moderate (KB = (1.1 ± 0.3) × 105 M−1). This finding shows that the reasoning behind the hypothesis that T20, already approved for clinical application in AIDS treatment, could inhibit the fusion of SARS-CoV with target cells is correct but the effect may not be strong enough for application.
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Affiliation(s)
- Salomé Veiga
- Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande C8, 1749-016 Lisboa, Portugal
| | - Yunyun Yuan
- Chinese Academy of Medical Sciences and Peking Union Medical College, Institute of Materia Medica, 1 Xian Nong Tan St., Beijing 100050, P. R. China
| | - Xuqin Li
- Chinese Academy of Medical Sciences and Peking Union Medical College, Institute of Materia Medica, 1 Xian Nong Tan St., Beijing 100050, P. R. China
| | - Nuno C. Santos
- Instituto de Biopatologia Química/Faculdade de Medicina de Lisboa and Unidade de Biopatologia Vascular/Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Gang Liu
- Chinese Academy of Medical Sciences and Peking Union Medical College, Institute of Materia Medica, 1 Xian Nong Tan St., Beijing 100050, P. R. China
| | - Miguel A.R.B. Castanho
- Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande C8, 1749-016 Lisboa, Portugal
- Corresponding author. Fax: +351 21 7500088.
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Zhu J, Jiang X, Liu Y, Tien P, Gao GF. Design and characterization of viral polypeptide inhibitors targeting Newcastle disease virus fusion. J Mol Biol 2005; 354:601-13. [PMID: 16253271 PMCID: PMC7094301 DOI: 10.1016/j.jmb.2005.08.078] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 08/28/2005] [Accepted: 08/31/2005] [Indexed: 11/23/2022]
Abstract
Paramyxovirus infections can be detected worldwide with some emerging zoonotic viruses and currently there are no specific therapeutic treatments or vaccines available for many of these diseases. Recent studies have demonstrated that peptides derived from the two heptad repeat regions (HR1 and HR2) of paramyxovirus fusion proteins could be used as inhibitors of virus fusion. The mechanism underlying this activity is in accordance with that of class I virus fusion proteins, of which human immunodeficiency virus (HIV) and influenza virus fusion proteins are members. For class I virus fusion proteins, the HR1 fragment binds to HR2 to form a six-helix bundle with three HR1 fragments forming the central coiled bundle surrounded by three coiled HR2 fragments in the post fusion conformational state (fusion core). It is hypothesized that the introduced exogenous HR1 or HR2 can compete against their endogenous counterparts, which results in fusion inhibition. Using Newcastle disease virus (NDV) as a model, we designed several protein inhibitors, denoted HR212 as well asHR121 and 5-Helix, which could bind the HR1 or HR2 region of fusion protein, respectively. All the proteins were expressed and purified using a GST-fusion expression system in Escherichia coli. The HR212 or GST-HR212 protein, which binds the HR1 peptide in vitro, displayed inhibitory activity against NDV-mediated cell fusion, while the HR121 and 5-Helix proteins, which bind the HR2 peptide in vitro, inhibited virus fusion from the avirulent NDV strain when added before the cleavage of the fusion protein. These results showed that the designed HR212, HR121 or 5-Helix protein could serve as specific antiviral agents. These data provide additional insight into the difference between the virulent and avirulent strains of NDV.
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Affiliation(s)
- Jieqing Zhu
- Center For Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Zhongguancun Beiyitiao, Beijing 100080, China
- Graduate School, Chinese Academy of Sciences, Yuquanlu, Beijing 100049, China
| | - Xiuli Jiang
- Department of Diarrhea Viruses, Institute for Viral Disease Control and Prevention, Chinese Center For Disease Control and Prevention (China CDC), 100# Yingxinjie, Xuanwuqu, Beijing 100052, China
| | - Yueyong Liu
- Center For Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Zhongguancun Beiyitiao, Beijing 100080, China
- Graduate School, Chinese Academy of Sciences, Yuquanlu, Beijing 100049, China
- Institute of Microbiology, College of Life Science, Zhejiang University, Hangzhou 310029, China
| | - Po Tien
- Center For Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Zhongguancun Beiyitiao, Beijing 100080, China
- Corresponding author.
| | - George F. Gao
- Center For Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Zhongguancun Beiyitiao, Beijing 100080, China
- Corresponding author.
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63
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Song C, Micoli K, Hunter E. Activity of the Mason-Pfizer monkey virus fusion protein is modulated by single amino acids in the cytoplasmic tail. J Virol 2005; 79:11569-79. [PMID: 16140734 PMCID: PMC1212599 DOI: 10.1128/jvi.79.18.11569-11579.2005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mason-Pfizer monkey virus (M-PMV) encodes a transmembrane glycoprotein with a 38-amino-acid-long cytoplasmic tail. After the release of the immature virus, a viral protease-mediated cleavage of the cytoplasmic tail (CT) results in the loss of 17 amino acids from the carboxy terminus and renders the envelope protein fusion competent. To investigate the role of individual amino acid residues in the CT in fusion, a series of mutations was introduced, and the effects of these mutations on glycoprotein biosynthesis and fusion were examined. Most of the alanine-scanning mutations in the CT had little effect on fusion activity. However, four amino acid substitutions (threonine 4, lysine 7, glutamine 9, and isoleucine 10) resulted in substantially increased fusogenicity, while six (leucine 2, phenylalanine 5, isoleucine 13, lysine 16, proline 17, and glycine 31) resulted in much-reduced fusion. Interestingly, the bulk of these mutations are located upstream of the CT cleavage site in a region that has the potential to form a coiled-coil in the Env trimer. Substitutions at glutamine 9 and isoleucine 10 with alanine had the most dramatic positive effect and resulted in the formation of large syncytia. Taken together, these data demonstrate that individual residues within the cytoplasmic domain of M-PMV Env can modulate, in both a positive and negative manner, biological functions that are associated with the extracellular domains of the glycoprotein complex.
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Affiliation(s)
- Chisu Song
- Department of Microbiology, University of Alabama at Birmingham, 35294, USA
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Bossart KN, Mungall BA, Crameri G, Wang LF, Eaton BT, Broder CC. Inhibition of Henipavirus fusion and infection by heptad-derived peptides of the Nipah virus fusion glycoprotein. Virol J 2005; 2:57. [PMID: 16026621 PMCID: PMC1208959 DOI: 10.1186/1743-422x-2-57] [Citation(s) in RCA: 57] [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: 05/24/2005] [Accepted: 07/18/2005] [Indexed: 11/10/2022] Open
Abstract
Background The recent emergence of four new members of the paramyxovirus family has heightened the awareness of and re-energized research on new and emerging diseases. In particular, the high mortality and person to person transmission associated with the most recent Nipah virus outbreaks, as well as the very recent re-emergence of Hendra virus, has confirmed the importance of developing effective therapeutic interventions. We have previously shown that peptides corresponding to the C-terminal heptad repeat (HR-2) of the fusion envelope glycoprotein of Hendra virus and Nipah virus were potent inhibitors of both Hendra virus and Nipah virus-mediated membrane fusion using recombinant expression systems. In the current study, we have developed shorter, second generation HR-2 peptides which include a capped peptide via amidation and acetylation and two poly(ethylene glycol)-linked (PEGylated) peptides, one with the PEG moity at the C-terminus and the other at the N-terminus. Here, we have evaluated these peptides as well as the corresponding scrambled peptide controls in Nipah virus and Hendra virus-mediated membrane fusion and against infection by live virus in vitro. Results Unlike their predecessors, the second generation HR-2 peptides exhibited high solubility and improved synthesis yields. Importantly, both Nipah virus and Hendra virus-mediated fusion as well as live virus infection were potently inhibited by both capped and PEGylated peptides with IC50 concentrations similar to the original HR-2 peptides, whereas the scrambled modified peptides had no inhibitory effect. These data also indicate that these chemical modifications did not alter the functional properties of the peptides as inhibitors. Conclusion Nipah virus and Hendra virus infection in vitro can be potently blocked by specific HR-2 peptides. The improved synthesis and solubility characteristics of the second generation HR-2 peptides will facilitate peptide synthesis for pre-clinical trial application in an animal model of Henipavirus infection. The applied chemical modifications are also predicted to increase the serum half-life in vivo and should increase the chance of success in the development of an effective antiviral therapy.
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Affiliation(s)
- Katharine N Bossart
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA
| | - Bruce A Mungall
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia
| | - Gary Crameri
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia
| | - Lin-Fa Wang
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia
| | - Bryan T Eaton
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia
| | - Christopher C Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA
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65
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Yin HS, Paterson RG, Wen X, Lamb RA, Jardetzky TS. Structure of the uncleaved ectodomain of the paramyxovirus (hPIV3) fusion protein. Proc Natl Acad Sci U S A 2005; 102:9288-93. [PMID: 15964978 PMCID: PMC1151655 DOI: 10.1073/pnas.0503989102] [Citation(s) in RCA: 253] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Class I viral fusion proteins share common mechanistic and structural features but little sequence similarity. Structural insights into the protein conformational changes associated with membrane fusion are based largely on studies of the influenza virus hemagglutinin in pre- and postfusion conformations. Here, we present the crystal structure of the secreted, uncleaved ectodomain of the paramyxovirus, human parainfluenza virus 3 fusion (F) protein, a member of the class I viral fusion protein group. The secreted human parainfluenza virus 3 F forms a trimer with distinct head, neck, and stalk regions. Unexpectedly, the structure reveals a six-helix bundle associated with the postfusion form of F, suggesting that the anchor-minus ectodomain adopts a conformation largely similar to the postfusion state. The transmembrane anchor domains of F may therefore profoundly influence the folding energetics that establish and maintain a metastable, prefusion state.
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Affiliation(s)
- Hsien-Sheng Yin
- Department of Biochemistry, Molecular Biology, and Cell Biology, Howard Hughes Medical Institute, Northwestern University, Evanston, IL 60208-3500, USA
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66
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Perez-Romero P, Fuller AO. The C terminus of the B5 receptor for herpes simplex virus contains a functional region important for infection. J Virol 2005; 79:7431-7. [PMID: 15919899 PMCID: PMC1143627 DOI: 10.1128/jvi.79.12.7431-7437.2005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of a previously uncharacterized human hfl-B5 cDNA confers susceptibility for herpes simplex virus (HSV) to porcine cells and fulfills criteria as an HSV entry receptor (A. Perez, Q.-X. Li, P. Perez-Romero, G. DeLassus, S. R. Lopez, S. Sutter, N. McLaren, and A. Oveta Fuller, J. Virol. 79:7419-7430, 2005). Heptad repeats found in the B5 C terminus are predicted to form an alpha-helix for coiled coil structure. We used mutagenesis and synthetic peptides with wild-type and mutant sequences to examine the function of the heptad repeat motif in HSV binding and entry into porcine cells that express B5 and for infection of naturally susceptible human HEp-2 cells. B5 with point mutations predicted to disrupt the putative C-terminal coiled coil failed to mediate HSV binding and entry into porcine cells. Synthetic peptides that contain the single amino acid changes lose the blocking activity of HSV entry. We concluded that the C terminus of B5 contains a functional region that is important for the B5 receptor to mediate events in HSV entry. Structural evidence that this functional region forms coiled coil structures is under investigation. Blocking of HSV interaction with the C-terminal region of the B5 receptor is a new potential target site to intervene in the virus infection of human cells.
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Affiliation(s)
- Pilar Perez-Romero
- Department of Microbiology and Immunology, 6736 Medical Sciences II, School of Medicine, University of Michigan, Ann Arbor, Michigan 48109-0620, USA
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67
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Ou W, Silver J. Inhibition of murine leukemia virus envelope protein (env) processing by intracellular expression of the env N-terminal heptad repeat region. J Virol 2005; 79:4782-92. [PMID: 15795264 PMCID: PMC1069576 DOI: 10.1128/jvi.79.8.4782-4792.2005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A conserved structural motif in the envelope proteins of several viruses consists of an N-terminal, alpha-helical, trimerization domain and a C-terminal region that refolds during fusion to bind the N-helix trimer. Interaction between the N and C regions is believed to pull viral and target membranes together in a crucial step during membrane fusion. For several viruses with type I fusion proteins, C regions pack as alpha-helices in the grooves between N-helix monomers, and exogenously added N- and C-region peptides block fusion by inhibiting the formation of the six-helix bundle. For other viruses, including influenza virus and murine leukemia virus (MLV), there is no evidence for comparably extended C-region alpha-helices, although a short, non-alpha-helical interaction structure has been reported for influenza virus. We tested candidate N-helix and C-region peptides from MLV for their ability to inhibit cell fusion but found no inhibitory activity. In contrast, intracellular expression of the MLV N-helix inhibited fusion by efficiently blocking proteolytic processing and intracellular transport of the envelope protein. The results highlight another mechanism by which the N-helix peptides can inhibit fusion.
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Affiliation(s)
- Wu Ou
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 4, Room 336, Bethesda, MD 20892, USA
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68
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Gower TL, Pastey MK, Peeples ME, Collins PL, McCurdy LH, Hart TK, Guth A, Johnson TR, Graham BS. RhoA signaling is required for respiratory syncytial virus-induced syncytium formation and filamentous virion morphology. J Virol 2005; 79:5326-36. [PMID: 15827147 PMCID: PMC1082718 DOI: 10.1128/jvi.79.9.5326-5336.2005] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Accepted: 12/21/2004] [Indexed: 11/20/2022] Open
Abstract
Respiratory syncytial virus (RSV) is an important human pathogen that can cause severe and life-threatening respiratory infections in infants, the elderly, and immunocompromised adults. RSV infection of HEp-2 cells induces the activation of RhoA, a small GTPase. We therefore asked whether RhoA signaling is important for RSV replication or syncytium formation. The treatment of HEp-2 cells with Clostridium botulinum C3, an enzyme that ADP-ribosylates and specifically inactivates RhoA, inhibited RSV-induced syncytium formation and cell-to-cell fusion, although similar levels of PFU were released into the medium and viral protein expression levels were equivalent. Treatment with another inhibitor of RhoA signaling, the Rho kinase inhibitor Y-27632, yielded similar results. Scanning electron microscopy of C3-treated infected cells showed reduced numbers of single blunted filaments, in contrast to the large clumps of long filaments in untreated infected cells. These data suggest that RhoA signaling is associated with filamentous virus morphology, cell-to-cell fusion, and syncytium formation but is dispensable for the efficient infection and production of infectious virus in vitro. Next, we developed a semiquantitative method to measure spherical and filamentous virus particles by using sucrose gradient velocity sedimentation. Fluorescence and transmission electron microscopy confirmed the separation of spherical and filamentous forms of infectious virus into two identifiable peaks. The C3 treatment of RSV-infected cells resulted in a shift to relatively more spherical virions than those from untreated cells. These data suggest that viral filamentous protuberances characteristic of RSV infection are associated with RhoA signaling, are important for filamentous virion morphology, and may play a role in initiating cell-to-cell fusion.
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Affiliation(s)
- Tara L Gower
- Vaccine Research Center, Building 40, Room 2502, NIAID, NIH, 40 Convent Dr., MSC 3017, Bethesda, MD 20892-3017, USA
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69
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Sainz B, Rausch JM, Gallaher WR, Garry RF, Wimley WC. The aromatic domain of the coronavirus class I viral fusion protein induces membrane permeabilization: putative role during viral entry. Biochemistry 2005; 44:947-58. [PMID: 15654751 DOI: 10.1021/bi048515g] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Coronavirus (CoV) entry is mediated by the viral spike (S) glycoprotein, a class I viral fusion protein. During viral and target cell membrane fusion, the heptad repeat (HR) regions of the S2 subunit assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes; however, the exact mechanism is unclear. Here, we characterize an aromatic amino acid rich region within the ectodomain of the S2 subunit that both partitions into lipid membranes and has the capacity to perturb lipid vesicle integrity. Circular dichroism analysis indicated that peptides analogous to the aromatic domains of the severe acute respiratory syndrome (SARS)-CoV, mouse hepatitis virus (MHV) and the human CoV OC43 S2 subunits, did not have a propensity for a defined secondary structure. These peptides strongly partitioned into lipid membranes and induced lipid vesicle permeabilization at peptide/lipid ratios of 1:100 in two independent leakage assays. Thus, partitioning of the peptides into the lipid interface is sufficient to disorganize membrane integrity. Our study of the S2 aromatic domain of three CoVs provides supportive evidence for a functional role of this region. We propose that, when aligned with the fusion peptide and transmembrane domains during membrane apposition, the aromatic domain of the CoV S protein functions to perturb the target cell membrane and provides a continuous track of hydrophobic surface, resulting in lipid-membrane fusion and subsequent viral nucleocapsid entry.
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Affiliation(s)
- Bruno Sainz
- Department of Microbiology and Immunology, Program in Molecular Pathogenesis and Immunity, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA
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70
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McDowell JV, Harlin ME, Rogers EA, Marconi RT. Putative coiled-coil structural elements of the BBA68 protein of Lyme disease spirochetes are required for formation of its factor H binding site. J Bacteriol 2005; 187:1317-23. [PMID: 15687195 PMCID: PMC545637 DOI: 10.1128/jb.187.4.1317-1323.2005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Factor H and factor H like-protein 1 (FHL-1) are complement regulatory proteins that serve as cofactors for the factor I-mediated cleavage of C3b. Some Lyme disease and relapsing fever spirochete species bind factor H to their surface to facilitate immune evasion. The Lyme disease spirochetes produce several factor H binding proteins (FHBPs) that form two distinct classes. Class I FHBPs (OspE orthologs and paralogs) bind only factor H, while class II FHBPs (BBA68) bind both factor H and FHL-1. BBA68 belongs to a large paralogous protein family, and of these paralogs, BBA69 is the member most closely related to BBA68. To determine if BBA69 can also bind factor H, recombinant protein was generated and tested for factor H binding. BBA69 did not exhibit factor H binding ability, suggesting that among family 54 paralogs, factor H binding is unique to BBA68. To identify the determinants of BBA68 that are involved in factor H binding, truncation and site-directed mutational analyses were performed. These analyses revealed that the factor H binding site is discontinuous and provide strong evidence that coiled-coil structural elements are involved in the formation of the binding site.
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Affiliation(s)
- John V McDowell
- Department of Microbiology and Immunology, Medical College of Virginia Commonwealth University, Richmond, VA 23298, USA
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71
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West DS, Sheehan MS, Segeleon PK, Dutch RE. Role of the simian virus 5 fusion protein N-terminal coiled-coil domain in folding and promotion of membrane fusion. J Virol 2005; 79:1543-51. [PMID: 15650180 PMCID: PMC544100 DOI: 10.1128/jvi.79.3.1543-1551.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Formation of a six-helix bundle comprised of three C-terminal heptad repeat regions in antiparallel orientation in the grooves of an N-terminal coiled-coil is critical for promotion of membrane fusion by paramyxovirus fusion (F) proteins. We have examined the effect of mutations in four residues of the N-terminal heptad repeat in the simian virus 5 (SV5) F protein on protein folding, transport, and fusogenic activity. The residues chosen have previously been shown from study of isolated peptides to have differing effects on stability of the N-terminal coiled-coil and six-helix bundle (R. E. Dutch, G. P. Leser, and R. A. Lamb, Virology 254:147-159, 1999). The mutant V154M showed reduced proteolytic cleavage and surface expression, indicating a defect in intracellular transport, though this mutation had no effect when studied in isolated peptides. The mutation I137M, previously shown to lower thermostability of the six-helix bundle, resulted in an F protein which was properly processed and transported to the cell surface but which had reduced fusogenic activity. Finally, mutations at L140M and L161M, previously shown to disrupt alpha-helix formation of isolated N-1 peptides but not to affect six-helix bundle formation, resulted in F proteins that were properly processed. Interestingly, the L161M mutant showed increased syncytium formation and promoted fusion at lower temperatures than the wild-type F protein. These results indicate that interactions separate from formation of an N-terminal coiled-coil or six-helix bundle are important in the initial folding and transport of the SV5 F protein and that mutations that destabilize the N-terminal coiled-coil can result in stimulation of membrane fusion.
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Affiliation(s)
- Dava S West
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 800 Rose St., UKMC MN606, Lexington, KY 40536-0298, USA
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72
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McDowell JV, Wolfgang J, Senty L, Sundy CM, Noto MJ, Marconi RT. Demonstration of the involvement of outer surface protein E coiled coil structural domains and higher order structural elements in the binding of infection-induced antibody and the complement-regulatory protein, factor H. THE JOURNAL OF IMMUNOLOGY 2005; 173:7471-80. [PMID: 15585873 DOI: 10.4049/jimmunol.173.12.7471] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Factor H (fH) is an important regulator of the alternative complement cascade. Several human pathogens have been shown to bind fH to their surface, a process that facilitates immune evasion or cell to cell interaction. Among the pathogens that bind fH are some Borrelia species associated with Lyme disease and relapsing fever. The fH-binding proteins of the Lyme spirochetes form two classes (I and II). In Borrelia burgdorferi B31MI, class I includes the outer surface protein E (OspE) paralogs, L39, N38, and P38, whereas the class II group includes A68 and additional proteins that have not yet been identified. To identify the OspE determinants involved in fH and OspE-targeting infection-induced Ab (iAb) binding, deletion, random, and site-directed mutagenesis of L39 were performed. Mutations in several different regions of L39 abolished fH and or iAb binding, indicating that separable domains and residues of OspE are required for ligand binding. Some of the mutants that lost the ability to bind fH, iAb, or both had only a single amino acid change. Site-directed mutagenesis of three putative coiled coil motifs of OspE revealed that these higher order structures are required for fH binding but not for iAb binding. The data presented within demonstrate that the binding of fH and iAb to the OspE protein is mediated by higher order structures and protein conformation. These studies advance our understanding of fH binding as a virulence mechanism and facilitate ongoing efforts to use fH-binding proteins in the development of microbial vaccines.
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MESH Headings
- Amino Acid Motifs/genetics
- Amino Acid Sequence
- Amino Acid Substitution/genetics
- Amino Acid Substitution/immunology
- Antibodies, Bacterial/biosynthesis
- Antibodies, Bacterial/metabolism
- Antigens, Bacterial/chemistry
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- Antigens, Bacterial/physiology
- Bacterial Outer Membrane Proteins/chemistry
- Bacterial Outer Membrane Proteins/genetics
- Bacterial Outer Membrane Proteins/immunology
- Bacterial Outer Membrane Proteins/physiology
- Bacterial Proteins/chemistry
- Bacterial Proteins/genetics
- Bacterial Proteins/immunology
- Bacterial Proteins/physiology
- Binding Sites, Antibody/genetics
- Borrelia/genetics
- Borrelia/immunology
- Borrelia/pathogenicity
- Complement Factor H/antagonists & inhibitors
- Complement Factor H/metabolism
- DNA Mutational Analysis
- Lipoproteins/chemistry
- Lipoproteins/genetics
- Lipoproteins/immunology
- Lipoproteins/physiology
- Lyme Disease/immunology
- Lyme Disease/metabolism
- Lyme Disease/microbiology
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Protein Binding/genetics
- Protein Binding/immunology
- Protein Structure, Secondary/genetics
- Protein Structure, Tertiary/genetics
- Sequence Deletion/immunology
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Affiliation(s)
- John V McDowell
- Department of Microbiology and Immunology, Medical College of Virginia at Virginia Commonwealth University, Richmond, VA 23298, USA
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73
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Abstract
Every enveloped virus fuses its membrane with a host cell membrane, thereby releasing its genome into the cytoplasm and initiating the viral replication cycle. In each case, one or a small set of viral surface transmembrane glycoproteins mediates fusion. Viral fusion proteins vary in their mode of activation and in structural class. These features combine to yield many different fusion mechanisms. Despite their differences, common principles for how fusion proteins function are emerging: In response to an activating trigger, the metastable fusion protein converts to an extended, in some cases rodlike structure, which inserts into the target membrane via its fusion peptide. A subsequent conformational change causes the fusion protein to fold back upon itself, thereby bringing its fusion peptide and its transmembrane domain-and their attached target and viral membranes-into intimate contact. Fusion ensues as the initial lipid stalk progresses through local hemifusion, and then opening and enlargement of a fusion pore. Here we review recent advances in our understanding of how fusion proteins are activated, how fusion proteins change conformation during fusion, and what is happening to the lipids during fusion. We also briefly discuss the therapeutic potential of fusion inhibitors in treating viral infections.
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Affiliation(s)
- Mark Marsh
- Cell Biology Unit, MRC-LMCB, University College London, Gower Street, London, WC1E 6BT UK
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74
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Volchkov VE, Volchkova VA, Dolnik O, Feldmann H, Klenk HD. Polymorphism of Filovirus Glycoproteins. Adv Virus Res 2005; 64:359-81. [PMID: 16139600 DOI: 10.1016/s0065-3527(05)64011-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Viktor E Volchkov
- Biologie des Filovirus, Claude Bernard University Lyon, INSERM U412 69365 Lyon, France
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75
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Barnard RJO, Narayan S, Dornadula G, Miller MD, Young JAT. Low pH is required for avian sarcoma and leukosis virus Env-dependent viral penetration into the cytosol and not for viral uncoating. J Virol 2004; 78:10433-41. [PMID: 15367609 PMCID: PMC516436 DOI: 10.1128/jvi.78.19.10433-10441.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel entry mechanism has been proposed for the avian sarcoma and leukosis virus (ASLV), whereby interaction with specific cell surface receptors activates or primes the viral envelope glycoprotein (Env), rendering it sensitive to subsequent low-pH-dependent fusion triggering in acidic intracellular organelles. However, ASLV fusion seems to proceed to a lipid mixing stage at neutral pH, leading to the suggestion that low pH might instead be required for a later stage of viral entry such as uncoating (L. J. Earp, S. E. Delos, R. C. Netter, P. Bates, and J. M. White. J. Virol. 77:3058-3066, 2003). To address this possibility, hybrid virus particles were generated with the core of human immunodeficiency virus type 1 (HIV-1), a known pH-independent virus, and with subgroups A or B ASLV Env proteins. Infection of cells by these pseudotyped virions was blocked by lysosomotropic agents, as judged by inhibition of HIV-1 DNA synthesis. Furthermore, by using HIV-1 cores that contain a Vpr-beta-lactamase fusion protein (Vpr-BlaM) to monitor viral penetration into the cytosol, we demonstrated that virions bearing ASLV Env, but not HIV-1 Env, enter the cytosol in a low-pH-dependent manner. This effect was independent of the presence of the cytoplasmic tail of ASLV Env. These studies provide strong support for the model, indicating that low pH is required for ASLV Env-dependent viral penetration into the cytosol and not for viral uncoating.
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Affiliation(s)
- Richard J O Barnard
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, USA
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76
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Cooper DA, Lange JMA. Peptide inhibitors of virus-cell fusion: enfuvirtide as a case study in clinical discovery and development. THE LANCET. INFECTIOUS DISEASES 2004; 4:426-36. [PMID: 15219553 DOI: 10.1016/s1473-3099(04)01058-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The peptidic antiretroviral enfuvirtide (Fuzeon) is the first clinically approved antiviral fusion inhibitor and the first antiretroviral that must routinely be administered parenterally. Its extracellular activity results both in activity against current drug-resistant strains of HIV-1 and a low potential for systemic toxicities. As a peptide, enfuvirtide also exhibits few interactions with other antiretrovirals and concomitant medications used in HIV disease. Enfuvirtide shows potent antiretroviral activity and significantly improves medical outcomes in highly treatment-experienced patients with HIV-1 infection, but like other antiretrovirals must be given as part of a carefully selected combination regimen to minimise the risk of emergent drug resistance. Despite its subcutaneous route of administration, clinical data indicate that most patients can accept long-term enfuvirtide treatment with little difficulty or impact on daily activities. The only common adverse event associated with enfuvirtide use is injection-site reactions of generally mild-to-moderate severity, which are seldom treatment-limiting.
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Affiliation(s)
- David A Cooper
- University of New South Wales, National Centre in HIV Epidemiology and Clinical Research, St Vincent's Hospital Medical Centre, Sydney, Australia.
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77
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Ingallinella P, Bianchi E, Finotto M, Cantoni G, Eckert DM, Supekar VM, Bruckmann C, Carfi A, Pessi A. Structural characterization of the fusion-active complex of severe acute respiratory syndrome (SARS) coronavirus. Proc Natl Acad Sci U S A 2004; 101:8709-14. [PMID: 15161975 PMCID: PMC423260 DOI: 10.1073/pnas.0402753101] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2003] [Indexed: 11/18/2022] Open
Abstract
The causative agent of a recent outbreak of an atypical pneumonia, known as severe acute respiratory syndrome (SARS), has been identified as a coronavirus (CoV) not belonging to any of the previously identified groups. Fusion of coronaviruses with the host cell is mediated by the envelope spike protein. Two regions within the spike protein of SARS-CoV have been identified, showing a high degree of sequence conservation with the other CoV, which are characterized by the presence of heptad repeats (HR1 and HR2). By using synthetic and recombinant peptides corresponding to the HR1 and HR2 regions, we were able to characterize the fusion-active complex formed by this novel CoV by CD, native PAGE, proteolysis protection analysis, and size-exclusion chromatography. HR1 and HR2 of SARS-CoV associate into an antiparallel six-helix bundle, with structural features typical of the other known class I fusion proteins. We have also mapped the specific boundaries of the region, within the longer HR1 domain, making contact with the shorter HR2 domain. Notably, the inner HR1 coiled coil is a stable alpha-helical domain even in the absence of interaction with the HR2 region. Inhibitors binding to HR regions of fusion proteins have been shown to be efficacious against many viruses, notably HIV. Our results may help in the design of anti-SARS therapeutics.
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Affiliation(s)
- Paolo Ingallinella
- Istituto di Ricerche di Biologia Molecolare P. Angeletti, Via Pontina Km 30.600, 00040 Pomezia, Italy
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78
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Bosch BJ, Martina BEE, Van Der Zee R, Lepault J, Haijema BJ, Versluis C, Heck AJR, De Groot R, Osterhaus ADME, Rottier PJM. Severe acute respiratory syndrome coronavirus (SARS-CoV) infection inhibition using spike protein heptad repeat-derived peptides. Proc Natl Acad Sci U S A 2004; 101:8455-60. [PMID: 15150417 PMCID: PMC420415 DOI: 10.1073/pnas.0400576101] [Citation(s) in RCA: 298] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The coronavirus SARS-CoV is the primary cause of the life-threatening severe acute respiratory syndrome (SARS). With the aim of developing therapeutic agents, we have tested peptides derived from the membrane-proximal (HR2) and membrane-distal (HR1) heptad repeat region of the spike protein as inhibitors of SARS-CoV infection of Vero cells. It appeared that HR2 peptides, but not HR1 peptides, were inhibitory. Their efficacy was, however, significantly lower than that of corresponding HR2 peptides of the murine coronavirus mouse hepatitis virus (MHV) in inhibiting MHV infection. Biochemical and electron microscopical analyses showed that, when mixed, SARS-CoV HR1 and HR2 peptides assemble into a six-helix bundle consisting of HR1 as a central triple-stranded coiled coil in association with three HR2 alpha-helices oriented in an antiparallel manner. The stability of this complex, as measured by its resistance to heat dissociation, appeared to be much lower than that of the corresponding MHV complex, which may explain the different inhibitory potencies of the HR2 peptides. Analogous to other class I viral fusion proteins, the six-helix complex supposedly represents a postfusion conformation that is formed after insertion of the fusion peptide, proposed here for coronaviruses to be located immediately upstream of HR1, into the target membrane. The resulting close apposition of fusion peptide and spike transmembrane domain facilitates membrane fusion. The inhibitory potency of the SARS-CoV HR2-peptides provides an attractive basis for the development of a therapeutic drug for SARS.
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Affiliation(s)
- Berend Jan Bosch
- Division of Virology, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, and Institute of Biomembranes, Utrecht University, 3584 CL Utrecht, The Netherlands
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79
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Xu Y, Gao S, Cole DK, Zhu J, Su N, Wang H, Gao GF, Rao Z. Basis for fusion inhibition by peptides: analysis of the heptad repeat regions of the fusion proteins from Nipah and Hendra viruses, newly emergent zoonotic paramyxoviruses. Biochem Biophys Res Commun 2004; 315:664-70. [PMID: 14975752 DOI: 10.1016/j.bbrc.2004.01.115] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Indexed: 11/24/2022]
Abstract
Nipah virus (NiV) and Hendra virus (HeV) are novel zoonotic members of the Paramyxoviridae family and are the prototypes for a newly designated genus, Genus Henipavirus. Recent studies have shown that paramyxovirus might adopt a similar mechanism of virus fusion-entry. Under this mechanism, the two highly conserved heptad repeat (HR) regions, HR1 and HR2, in the fusion (F) protein, seem to show characteristic structure in the fusion core: the formation of a 6-helix coiled-coil bundle. The three HR1s form the alpha-helix coiled-coil surrounded by three HR2s. In this study, the two HR regions of NiV or HeV were expressed in an Escherichia coli system as a single chain and the results do show that HR1 and HR2 interact with each other in both NiV and HeV and form typical 6-helix coiled-coil bundles. This provides the molecular basis of HR2 inhibition to NiV and HeV fusion as observed in an earlier report.
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Affiliation(s)
- Yanhui Xu
- Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China
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80
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Abstract
Infection by all enveloped viruses occurs via the fusion of viral and cellular membranes and delivery of the viral nucleocapsid into the cell cytoplasm, after association of the virus with cognate receptors at the cell surface. This process is mediated by viral fusion proteins anchored in the viral envelope and can be defined based on the requirement for low pH to trigger membrane fusion. In viruses that utilize a pH-dependent entry mechanism, such as influenza virus, viral fusion is triggered by the acidic environment of intracellular organelles after uptake of the virus from the cell surface and trafficking to a low-pH compartment. In contrast, in viruses that utilize a pH-independent entry mechanism, such as most retroviruses, membrane fusion is triggered solely by the interaction of the envelope glycoprotein with cognate receptors, often at the cell surface. However, recent work has indicated that the alpharetrovirus, avian sarcoma and leukosis virus (ASLV), utilizes a novel entry mechanism that combines aspects of both pH-independent and pH-dependent entry. In ASLV infection, the interaction of the envelope glycoprotein (Env) with cognate receptors at the cell surface causes an initial conformational change that primes (activates) Env and renders it sensitive to subsequent low-pH triggering from an intracellular compartment. Thus unlike other pH-dependent viruses, ASLV Env is only sensitive to low-pH triggering following interaction with its cognate receptor. In this manuscript we review current research on ASLV Env-receptor interactions and focus on the specific molecular requirements of both the viral fusion protein and cognate receptors for ASLV entry. In addition, we review data pertaining to the novel two-step entry mechanism of ASLV entry and propose a model by which ASLV Env elicits membrane fusion.
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Affiliation(s)
- R J O Barnard
- McArdle Laboratories for Cancer Research, Department of Oncology, University of Wisconsin Madison, 1400 University Ave, Madison, WI 53706, USA
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81
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Russell CJ, Kantor KL, Jardetzky TS, Lamb RA. A dual-functional paramyxovirus F protein regulatory switch segment: activation and membrane fusion. ACTA ACUST UNITED AC 2003; 163:363-74. [PMID: 14581458 PMCID: PMC2173521 DOI: 10.1083/jcb.200305130] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many viral fusion–mediating glycoproteins couple α-helical bundle formation to membrane merger, but have different methods for fusion activation. To study paramyxovirus-mediated fusion, we mutated the SV5 fusion (F) protein at conserved residues L447 and I449, which are adjacent to heptad repeat (HR) B and bind to a prominent cavity in the HRA trimeric coiled coil in the fusogenic six-helix bundle (6HB) structure. These analyses on residues L447 and I449, both in intact F protein and in 6HB, suggest a metamorphic region around these residues with dual structural roles. Mutation of L447 and I449 to aliphatic residues destabilizes the 6HB structure and attenuates fusion activity. Mutation of L447 and I449 to aromatic residues also destabilizes the 6HB structure despite promoting hyperactive fusion, indicating that 6HB stability alone does not dictate fusogenicity. Thus, residues L447 and I449 adjacent to HRB in paramyxovirus F have distinct roles in fusion activation and 6HB formation, suggesting this region is involved in a conformational switch.
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82
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Abstract
The activation of most paramyxovirus fusion proteins (F proteins) requires not only cleavage of F(0) to F(1) and F(2) but also coexpression of the homologous attachment protein, hemagglutinin-neuraminidase (HN) or hemagglutinin (H). The type specificity requirement for HN or H protein coexpression strongly suggests that an interaction between HN and F proteins is required for fusion, and studies of chimeric HN proteins have implicated the membrane-proximal ectodomain in this interaction. Using biotin-labeled peptides with sequences of the Newcastle disease virus (NDV) F protein heptad repeat 2 (HR2) domain, we detected a specific interaction with amino acids 124 to 152 from the NDV HN protein. Biotin-labeled HR2 peptides bound to glutathione S-transferase (GST) fusion proteins containing these HN protein sequences but not to GST or to GST containing HN protein sequences corresponding to amino acids 49 to 118. To verify the functional significance of the interaction, two point mutations in the HN protein gene, I133L and L140A, were made individually by site-specific mutagenesis to produce two mutant proteins. These mutations inhibited the fusion promotion activities of the proteins without significantly affecting their surface expression, attachment activities, or neuraminidase activities. Furthermore, these changes in the sequence of amino acids 124 to 152 in the GST-HN fusion protein that bound HR2 peptides affected the binding of the peptides. These results are consistent with the hypothesis that HN protein binds to the F protein HR2 domain, an interaction important for the fusion promotion activity of the HN protein.
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Affiliation(s)
- Kathryn A Gravel
- Program in Immunology and Virology, Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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83
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Bosch BJ, van der Zee R, de Haan CAM, Rottier PJM. The coronavirus spike protein is a class I virus fusion protein: structural and functional characterization of the fusion core complex. J Virol 2003; 77:8801-11. [PMID: 12885899 PMCID: PMC167208 DOI: 10.1128/jvi.77.16.8801-8811.2003] [Citation(s) in RCA: 1042] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Coronavirus entry is mediated by the viral spike (S) glycoprotein. The 180-kDa oligomeric S protein of the murine coronavirus mouse hepatitis virus strain A59 is posttranslationally cleaved into an S1 receptor binding unit and an S2 membrane fusion unit. The latter is thought to contain an internal fusion peptide and has two 4,3 hydrophobic (heptad) repeat regions designated HR1 and HR2. HR2 is located close to the membrane anchor, and HR1 is some 170 amino acids (aa) upstream of it. Heptad repeat (HR) regions are found in fusion proteins of many different viruses and form an important characteristic of class I viral fusion proteins. We investigated the role of these regions in coronavirus membrane fusion. Peptides HR1 (96 aa) and HR2 (39 aa), corresponding to the HR1 and HR2 regions, were produced in Escherichia coli. When mixed together, the two peptides were found to assemble into an extremely stable oligomeric complex. Both on their own and within the complex, the peptides were highly alpha helical. Electron microscopic analysis of the complex revealed a rod-like structure approximately 14.5 nm in length. Limited proteolysis in combination with mass spectrometry indicated that HR1 and HR2 occur in the complex in an antiparallel fashion. In the native protein, such a conformation would bring the proposed fusion peptide, located in the N-terminal domain of HR1, and the transmembrane anchor into close proximity. Using biological assays, the HR2 peptide was shown to be a potent inhibitor of virus entry into the cell, as well as of cell-cell fusion. Both biochemical and functional data show that the coronavirus spike protein is a class I viral fusion protein.
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Affiliation(s)
- Berend Jan Bosch
- Virology Division, Department of Infectious Diseases and Immunity, Faculty of Veterinary Medicine, and Institute of Biomembranes, Utrecht University, 3584 CL Utrecht, The Netherlands
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84
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Ludwig K, Baljinnyam B, Herrmann A, Böttcher C. The 3D structure of the fusion primed Sendai F-protein determined by electron cryomicroscopy. EMBO J 2003; 22:3761-71. [PMID: 12881411 PMCID: PMC169058 DOI: 10.1093/emboj/cdg385] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The three dimensional (3D) structure of the ectodomain of the entire fusion mediating F protein from Sendai virus [MW (trimer) approximately 177 kDa] has been determined by cryoelectron microscopy of single molecules and subsequent 3D reconstruction at a resolution of approximately 16 A. The reconstruction, which has been obtained from the native, proteolytic processed fusion primed F1+F2 form, shows the protein protruding approximately 170 A out of the membrane in a homotrimeric association. It consists of a defined approximately 65 A wide distal head and an adjacent neck, which is connected to an 70 A elongated stalk. Although the overall shape appears to be similar to the recently reported X-ray structure of the Newcastle disease virus F protein, a closer comparison reveals structural differences suggesting that the investigated Sendai F structure represents an advanced state towards the fusion active conformation.
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Affiliation(s)
- Kai Ludwig
- Forschungszentrum für Elektronenmikroskopie, Freie Universität Berlin, Berlin, Germany
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85
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Morrison TG. Structure and function of a paramyxovirus fusion protein. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1614:73-84. [PMID: 12873767 DOI: 10.1016/s0005-2736(03)00164-0] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Paramyxoviruses initiate infection by attaching to cell surface receptors and fusing viral and cell membranes. Viral attachment proteins, hemagglutinin-neuraminidase (HN), hemagglutinin (HA), or glycoprotein (G), bind receptors while fusion (F) proteins direct membrane fusion. Because paramyxovirus fusion is pH independent, virus entry occurs at host cell plasma membranes. Paramyxovirus fusion also usually requires co-expression of both the attachment protein and the fusion (F) protein. Newcastle disease virus (NDV) has assumed increased importance as a prototype paramyxovirus because crystal structures of both the NDV F protein and the attachment protein (HN) have been determined. Furthermore, analysis of structure and function of both viral glycoproteins by mutation, reactivity of antibody, and peptides have defined domains of the NDV F protein important for virus fusion. These domains include the fusion peptide, the cytoplasmic domain, as well as heptad repeat (HR) domains. Peptides with sequences from HR domains inhibit fusion, and characterization of the mechanism of this inhibition provides evidence for conformational changes in the F protein upon activation of fusion. Both proteolytic cleavage of the F protein and interactions with the attachment protein are required for fusion activation in most systems. Subsequent steps in membrane merger directed by F protein are poorly understood.
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Affiliation(s)
- Trudy G Morrison
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
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86
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Song C, Hunter E. Variable sensitivity to substitutions in the N-terminal heptad repeat of Mason-Pfizer monkey virus transmembrane protein. J Virol 2003; 77:7779-85. [PMID: 12829817 PMCID: PMC161947 DOI: 10.1128/jvi.77.14.7779-7785.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The transmembrane protein of Mason-Pfizer monkey virus contains two heptad repeats that are predicted to form amphipathic alpha-helices that mediate the conformational change necessary for membrane fusion. To analyze the relative sensitivity of the predicted hydrophobic face of the N-terminal heptad repeat to the insertion of uncharged, polar, and charged substitutions, mutations that introduced alanine, serine, or glutamic acid into positions 436, 443, 450, and 457 of the envelope protein were examined. Novel systems using Tat protein and the GHOST cell line were developed to test and quantitate the effects of the mutations on Env-mediated fusion and infectivity of the virus. While no single amino acid change at any of the positions interfered significantly with the synthesis, processing, or transport to the plasma membrane of glycoprotein complexes, 9 of the 12 nonconservative mutations in these residues completely abolished fusion activity and virus infectivity. Mutations in the central positions (443 and 450) of the heptad repeat region were the most detrimental to Env function, and even single alanine substitutions in these positions dramatically altered the fusogenicity of the protein. These results demonstrate that this N-terminal heptad repeat plays a critical role in Env-mediated membrane fusion and highlight the key function of central hydrophobic residues in this process and the sensitivity of all positions to charge substitutions.
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Affiliation(s)
- Chisu Song
- Department of Microbiology and Center for AIDS Research, University of Alabama at Birmingham, 845 19th Street S., Birmingham, AL 35294, USA
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87
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Zwick MB, Parren PWHI, Saphire EO, Church S, Wang M, Scott JK, Dawson PE, Wilson IA, Burton DR. Molecular features of the broadly neutralizing immunoglobulin G1 b12 required for recognition of human immunodeficiency virus type 1 gp120. J Virol 2003; 77:5863-76. [PMID: 12719580 PMCID: PMC154005 DOI: 10.1128/jvi.77.10.5863-5876.2003] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2002] [Accepted: 02/14/2003] [Indexed: 01/11/2023] Open
Abstract
IgG1 b12 is a broadly neutralizing antibody against human immunodeficiency virus type 1 (HIV-1). The epitope recognized by b12 overlaps the CD4 receptor-binding site (CD4bs) on gp120 and has been a target for vaccine design. Determination of the three-dimensional structure of immunoglobulin G1 (IgG1) b12 allowed modeling of the b12-gp120 interaction in which the protruding third complementarity-determining region (CDR) of the heavy chain (H3) was crucial for antibody binding. In the present study, extensive mutational analysis of the antigen-binding site of Fab b12 was carried out to investigate the validity of the model and to identify residues important for gp120 recognition and, by inference, key to the anti-HIV-1 activity of IgG1 b12. In all, 50 mutations were tested: 40 in H3, 4 each in H2 and L1, and 2 in L3. The results suggest that the interaction of gp120 with H3 of b12 is crucially dependent not only on a Trp residue at the apex of the H3 loop but also on a number of residues at the base of the loop. The arrangement of these residues, including aromatic side chains and side chains that hydrogen bond across the base of the loop, may rigidify H3 for penetration of the recessed CD4-binding cavity. The results further emphasize the importance to gp120 binding of a Tyr residue at the apex of the H2 loop that forms a second finger-like structure and a number of Arg residues in L1 that form a positively charged, shelf-like structure. In general, the data are consistent with the b12-gp120 interaction model previously proposed. At the gene level, somatic mutation is seen to be crucial for the generation of many of the structural features described. The Fab b12 mutants were also tested against the b12 epitope-mimic peptide B2.1, and the reactivity profile had many similarities but also significant differences from that observed for gp120. The paratope map of b12 may facilitate the design of molecules that are able to elicit b12-like activities.
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Affiliation(s)
- Michael B Zwick
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA
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88
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Wang E, Sun X, Qian Y, Zhao L, Tien P, Gao GF. Both heptad repeats of human respiratory syncytial virus fusion protein are potent inhibitors of viral fusion. Biochem Biophys Res Commun 2003; 302:469-75. [PMID: 12615056 DOI: 10.1016/s0006-291x(03)00197-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heptad repeat regions (HR1 and HR2) are highly conserved peptides located in F(1) of paramyxovirus envelope proteins. They are important in the process of virus fusion and form six-helix bundle structure (trimer of HR1 and HR2 heterodimer) post-fusion, similar to those found in the fusion proteins of other enveloped viruses, such as retrovirus HIV. Both HR1 and HR2 show potent inhibition for virus fusion in some members of paramyxovirus. However, in other members, only HR2 gives strong inhibition whereas HR1 does not. Human respiratory syncytial virus (hRSV) is a member of paramyxovirus and its crystal structure of HR1 and HR2 six-helix bundle was solved lately. Although hRSV HR2 inhibition was reported, nevertheless the effect of HR1 on virus fusion is not known. In this study, hRSV HR1 and HR2 were expressed as fusion protein separately in Escherichia coli system and their complex assembly and virus fusion inhibition effect have been analysed. It shows that both HR1 and HR2 (in the fusion form with 50-amino-acid fusion partner) of hRSV F protein give strong inhibition on virus fusion (IC(50) values are 1.68 and 2.93 microM, respectively) and they form stable six-helix bundle in vitro with both in the fusion protein form.
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Affiliation(s)
- Enxiu Wang
- Department of Molecular Virology and Bio-Engineering, Institute of Microbiology, Chinese Academy of Sciences, Zhongguancun Beiyitiao, Beijing 100080, China
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89
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Rahaman A, Srinivasan N, Shamala N, Shaila MS. The fusion core complex of the peste des petits ruminants virus is a six-helix bundle assembly. Biochemistry 2003; 42:922-31. [PMID: 12549911 DOI: 10.1021/bi026858d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe the properties of the two heptad repeats (HR1 and HR2) of the Peste des petits ruminants virus (PPRV) fusion protein (F) to obtain insights into the mechanism by which these repeats influence PPRV-mediated cell fusion. Both HR1 and HR2 inhibit PPRV-mediated syncytia formation in Vero cells in vitro. Of these, HR2 was found to be more effective than HR1. We studied the mechanism of fusion inhibition by these two repeats by using various biophysical and biochemical methods either separately or together. CD spectral analysis of these repeats revealed that the alpha-helical content of HR1 and HR2 when used together is higher than that of their simulated spectrum in the mixture, suggesting the formation of a highly structured complex by these repeats. Protease protection assays confirmed that such a complex is highly stable. Electrospray mass spectrometry of protease-digested products of the HR1-HR2 complex showed protection of fragments corresponding to both HR1 and HR2 sequences involved in complex formation. By employing size-exclusion chromatography and chemical cross-linking experiments, we show that three units each of HR1 and HR2 form a complex in which HR1 is a trimer and HR2 is a monomer. Homology-based three-dimensional modeling of this complex showed that HR1 and HR2 together form a six-helix and trimeric coiled-coil bundle. In this model, the HR1 trimer forms the core whereas HR2, while interacting with HR1 in an antiparallel orientation, forms a two-stranded coiled-coil structure and lies at the periphery of the structure. These results are discussed in the context of a common fusion mechanism among paramyxoviruses.
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Affiliation(s)
- Abdur Rahaman
- Department of Microbiology and Cell Biology, Molecular Biophysics Unit, and Department of Physics, Indian Institute of Science, Bangalore 560012, India
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90
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Seth S, Vincent A, Compans RW. Mutations in the cytoplasmic domain of a paramyxovirus fusion glycoprotein rescue syncytium formation and eliminate the hemagglutinin-neuraminidase protein requirement for membrane fusion. J Virol 2003; 77:167-78. [PMID: 12477822 PMCID: PMC140627 DOI: 10.1128/jvi.77.1.167-178.2003] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
SER virus is closely related to the paramyxovirus simian virus 5 (SV5) but is defective in syncytium formation. The SER virus F protein has a long cytoplasmic tail (CT) domain that has been shown to inhibit membrane fusion, and this inhibitory effect could be eliminated by truncation of the C-terminal sequence (S. Tong, M. Li, A. Vincent, R. W. Compans, E. Fritsch, R. Beier, C. Klenk, M. Ohuchi, and H.-D. Klenk, Virology 301:322-333, 2002). To study the sequence requirements for regulation of fusion, codons for SER virus F protein residues spanning amino acids 535 to 542 and 548 were mutated singly to alanines, and the two leucine residues at positions 539 and 548 were mutated doubly to alanines. We found that leu-539 and leu-548 in the CT domain played a critical role in the inhibition of fusion, as mutation of the two leucines singly to alanines partially rescued fusion, and the double mutation L539, 548A completely rescued syncytium formation. Mutation of charged residues to alanines had little effect on the suppression of fusion activity, whereas the mutation of serine residues to alanines enhanced fusion activity significantly. The L539, 548A mutant also showed extensive syncytium formation when expressed without the SER virus HN protein. By constructing a chimeric SV5-SER virus F CT protein, we also found that the inhibitory effect of the long CT of the SER virus F protein could be partially transferred to the SV5 F protein. These results demonstrate that an elongated CT of a paramyxovirus F protein interferes with membrane fusion in a sequence-dependent manner.
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Affiliation(s)
- Shaguna Seth
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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91
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Zhu J, Zhang CWH, Qi Y, Tien P, Gao GF. The fusion protein core of measles virus forms stable coiled-coil trimer. Biochem Biophys Res Commun 2002; 299:897-902. [PMID: 12470664 DOI: 10.1016/s0006-291x(02)02761-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent studies have shown that paramyxovirus might adopt a similar molecular mechanism of virus entry and fusion in which the attachment glycoprotein binds receptor/s and triggers the conformational changes of the fusion protein. There are two conserved regions of heptad repeat (HR1 and HR2) in the fusion protein and they were shown with fusion-inhibition effects in many paramyxoviruses, including measles virus. They also appear to show characteristic structure in the fusion core: the HR1/HR2 forms stable six-helix coiled-coil centered by HR1 and is surrounded by HR2 (trimer of HR1/HR2), which represents the post-fusion conformational structure. In this study, we expressed the HR1 and HR2 of measles virus fusion protein as a single chain (named 2-Helix) and subsequently tested its formation of trimer. Indeed, the results do show that the HR1 and HR2 interact with each other and form stable six-helix coiled-coil bundle. This is the first member in genus Morbillivirus of family Paramyxoviridae to be confirmed with this characteristic structure and provides the basis for the HR2-inhibition effects on virus fusion/entry for measles virus.
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Affiliation(s)
- Jieqing Zhu
- Department of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Zhongguancun Beiyitiao, Beijing 100080, China
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92
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McGinnes LW, Gravel K, Morrison TG. Newcastle disease virus HN protein alters the conformation of the F protein at cell surfaces. J Virol 2002; 76:12622-33. [PMID: 12438588 PMCID: PMC136696 DOI: 10.1128/jvi.76.24.12622-12633.2002] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Conformational changes in the Newcastle disease virus (NDV) fusion (F) protein during activation of fusion and the role of HN protein in these changes were characterized with a polyclonal antibody. This antibody was raised against a peptide with the sequence of the amino-terminal half of the F protein HR1 domain. This antibody immunoprecipitated both F(0) and F(1) forms of the fusion protein from infected and transfected cell extracts solubilized with detergent, and precipitation was unaffected by expression of the HN protein. In marked contrast, this antibody detected significant conformational differences in the F protein at cell surfaces, differences that depended upon HN protein expression. The antibody minimally detected the F protein, either cleaved or uncleaved, in the absence of HN protein expression. However, when coexpressed with HN protein, an uncleaved mutant F protein bound the anti-HR1 antibody, and this binding depended upon the coexpression of specifically the NDV HN protein. When the cleaved wild-type F protein was coexpressed with HN protein, the F protein bound anti-HR1 antibody poorly although significantly more than F protein expressed alone. Anti-HR1 antibody inhibited the fusion of R18 (octadecyl rhodamine B chloride)-labeled red blood cells to syncytia expressing HN and wild-type F proteins. This inhibition showed that fusion-competent F proteins present on surfaces of syncytia were capable of binding anti-HR1. Furthermore, only antibody which was added prior to red blood cell binding could inhibit fusion. These results suggest that the conformation of uncleaved cell surface F protein is affected by HN protein expression. Furthermore, the cleaved F protein, when coexpressed with HN protein and in a prefusion conformation, can bind anti-HR1 antibody, and the anti-HR1-accessible conformation exists prior to HN protein attachment to receptors on red blood cells.
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Affiliation(s)
- Lori W McGinnes
- Department of Molecular Genetics and Microbiology/Program in Immunology and Virology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655
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93
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Bossart KN, Wang LF, Flora MN, Chua KB, Lam SK, Eaton BT, Broder CC. Membrane fusion tropism and heterotypic functional activities of the Nipah virus and Hendra virus envelope glycoproteins. J Virol 2002; 76:11186-98. [PMID: 12388678 PMCID: PMC136767 DOI: 10.1128/jvi.76.22.11186-11198.2002] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nipah virus (NiV) and Hendra virus (HeV) are novel paramyxoviruses from pigs and horses, respectively, that are responsible for fatal zoonotic infections of humans. The unique genetic and biological characteristics of these emerging agents has led to their classification as the prototypic members of a new genus within the Paramyxovirinae subfamily called HENIPAVIRUS: These viruses are most closely related to members of the genus Morbillivirus and infect cells through a pH-independent membrane fusion event mediated by the actions of their attachment (G) and fusion (F) glycoproteins. Understanding their cell biological features and exploring the functional characteristics of the NiV and HeV glycoproteins will help define important properties of these emerging viruses and may provide new insights into paramyxovirus membrane fusion mechanisms. Using a recombinant vaccinia virus system and a quantitative assay for fusion, we demonstrate NiV glycoprotein function and the same pattern of cellular tropism recently reported for HeV-mediated fusion, suggesting that NiV likely uses the same cellular receptor for infection. Fusion specificity was verified by inhibition with a specific antiserum or peptides derived from the alpha-helical heptads of NiV or HeV F. Like that of HeV, NiV-mediated fusion also requires both F and G. Finally, interactions between the glycoproteins of the paramyxoviruses have not been well defined, but here we show that the NiV and HeV glycoproteins are capable of highly efficient heterotypic functional activity with each other. However, no heterotypic activity was observed with envelope glycoproteins of the morbilliviruses Measles virus and Canine distemper virus.
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Affiliation(s)
- Katharine N Bossart
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland 20814, USA
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94
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San Román K, Villar E, Muñoz-Barroso I. Mode of action of two inhibitory peptides from heptad repeat domains of the fusion protein of Newcastle disease virus. Int J Biochem Cell Biol 2002; 34:1207-20. [PMID: 12127571 DOI: 10.1016/s1357-2725(02)00045-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptides derived from heptad repeat (HR) sequences of viral fusion proteins from several enveloped viruses have been shown to inhibit virus-mediated membrane fusion but the mechanism remains unknown. To further investigate this, the inhibition mechanism of two HR-derived peptides from the fusion protein of the paramyxovirus Newcastle disease virus (NDV) was investigated. Peptide N24 (residues 145-168) derived from HR1 was found to be 145-fold more inhibitory in a syncytium assay than peptide C24 (residues 474-496), derived from HR2. Both peptides failed to block lipid-mixing between R18-labeled virus and cells. None of the peptides interfered with the binding of hemagglutinin-neuraminidase (HN) protein to the target cells, as demonstrated by hemagglutining assays. When both peptides were mixed at equimolar concentrations, their inhibitory effect was abolished. In addition, both peptides induced the aggregation of negatively charged and zwitterionic phospholipid membranes. The ability of the peptides to interact with each other in solution suggests that these peptides may bind to the opposite HR region on the protein whereas their ability to interact with membranes as well as their failure to block lipid transfer suggest a second binding site. Taken together these results, suggest a mode of action for C24 and N24 in which both peptides have two different targets on the F protein: the opposite HR sequence and their corresponding domains.
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Affiliation(s)
- K San Román
- Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, Edificio Departamental Lab. 109, Plaza Doctores de la Reina s/n, 37007 Salamanca, Spain
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95
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Tong S, Li M, Vincent A, Compans RW, Fritsch E, Beier R, Klenk C, Ohuchi M, Klenk HD. Regulation of fusion activity by the cytoplasmic domain of a paramyxovirus F protein. Virology 2002; 301:322-333. [PMID: 12359434 DOI: 10.1006/viro.2002.1594] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
SER virus is a member of the family Paramyxoviridae, genus Rubulavirus, which has been isolated from pigs. It is very closely related to SV5 virus serologically, in protein profile, and in nucleotide sequence. However, unlike SV5, SER induces minimal syncytium formation in infected CV-1 or BHK cells. Fluorescence transfer experiments between labeled erythrocytes and infected MDBK cells revealed that SER also induces hemifusion and pore formation with reduced efficiency. The virion polypeptide profiles of SER and SV5 are very similar, except that the SER F1 subunit shows an apparent molecular weight that is about 2 kDa higher than that of SV5. Comparison of the deduced amino acid sequences revealed the SER F (551 aa) to be longer than SV5 F (529 aa) by 22 residues in the cytoplasmic tail (CT) domain. The HN and M gene sequences of the viruses were found to be very similar. The SER F showed minimal fusion activity when coexpressed with either SV5 or SER HN. In contrast, SV5 F was highly fusogenic when coexpressed with either HN protein, indicating that the restricted fusion capacity of SER virus is a property of its F protein. Truncation in the CT of SER F by 22 residues completely rescued its ability to cause syncytium formation, whereas other truncations rescued syncytium formation partially. These results demonstrate that an elongated CT of a paramyxovirus F protein suppresses its membrane fusion activity.
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Affiliation(s)
- S Tong
- Department of Microbiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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96
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Pearson MN, Rohrmann GF. Transfer, incorporation, and substitution of envelope fusion proteins among members of the Baculoviridae, Orthomyxoviridae, and Metaviridae (insect retrovirus) families. J Virol 2002; 76:5301-4. [PMID: 11991958 PMCID: PMC137044 DOI: 10.1128/jvi.76.11.5301-5304.2002] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Margot N Pearson
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331-3804, USA
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97
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Lewicki DN, Gallagher TM. Quaternary structure of coronavirus spikes in complex with carcinoembryonic antigen-related cell adhesion molecule cellular receptors. J Biol Chem 2002; 277:19727-34. [PMID: 11912215 PMCID: PMC8060896 DOI: 10.1074/jbc.m201837200] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Oligomeric spike (S) glycoproteins extend from coronavirus membranes. These integral membrane proteins assemble within the endoplasmic reticulum of infected cells and are subsequently endoproteolyzed in the Golgi, generating noncovalently associated S1 and S2 fragments. Once on the surface of infected cells and virions, peripheral S1 fragments bind carcinoembryonic antigen-related cell adhesion molecule (CEACAM) receptors, and this triggers membrane fusion reactions mediated by integral membrane S2 fragments. We focused on the quaternary structure of S and its interaction with CEACAMs. We discovered that soluble S1 fragments were dimers and that CEACAM binding was entirely dependent on this quaternary structure. However, two differentially tagged CEACAMs could not co-precipitate with the S dimers, suggesting that binding sites were closely juxtaposed in the dimer (steric hindrance) or that a single CEACAM generated global conformational changes that precluded additional interactions (negative cooperativity). CEACAM binding did indeed alter S1 conformations, generating alternative disulfide linkages that were revealed on SDS gels. CEACAM binding also induced separation of S1 and S2. Differentially tagged S2 fragments that were free of S1 dimers were not co-precipitated, suggesting that S1 harbored the primary oligomerization determinants. We discuss the distinctions between the S.CEACAM interaction and other virus-receptor complexes involved in receptor-triggered entry.
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Affiliation(s)
- Daniel N Lewicki
- Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, Illinois 60153, USA
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98
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Abstract
Viral envelope glycoproteins promote viral infection by mediating the fusion of the viral membrane with the host-cell membrane. Structural and biochemical studies of two viral glycoproteins, influenza hemagglutinin and HIV-1 envelope protein, have led to a common model for viral entry. The fusion mechanism involves a transient conformational species that can be targeted by therapeutic strategies. This mechanism of infectivity is likely utilized by a wide variety of enveloped viruses for which similar therapeutic interventions should be possible.
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Affiliation(s)
- D M Eckert
- Howard Hughes Medical Institute, Whitehead Institute for Biomedical Research, Department of Biology, M.I.T., Cambridge, Massachusetts 02142, USA.
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99
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Yu M, Wang E, Liu Y, Cao D, Jin N, Zhang CWH, Bartlam M, Rao Z, Tien P, Gao GF. Six-helix bundle assembly and characterization of heptad repeat regions from the F protein of Newcastle disease virus. J Gen Virol 2002; 83:623-629. [PMID: 11842257 DOI: 10.1099/0022-1317-83-3-623] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Paramyxoviruses may adopt a similar fusion mechanism to other enveloped viruses, in which an anti-parallel six-helix bundle structure is formed post-fusion in the heptad repeat (HR) regions of the envelope fusion protein. In order to understand the fusion mechanism and identify fusion inhibitors of Newcastle disease virus (NDV), a member of the Paramyxoviridae family, we have developed an E. coli system that separately expresses the F protein HR1 and HR2 regions as GST fusion proteins. The purified cleaved HR1 and HR2 have subsequently been assembled into a stable six-helix bundle heterotrimer complex. Furthermore, both the GST fusion protein and the cleaved HR2 show virus-cell fusion inhibition activity (IC(50) of 1.07-2.93 microM). The solubility of the GST-HR2 fusion protein is much higher than that of the corresponding peptide. Hence this provides a plausible method for large-scale production of HR peptides as virus fusion inhibitors.
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Affiliation(s)
- Ming Yu
- Dept of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China1
| | - Enxiu Wang
- Dept of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China1
| | - Youfang Liu
- Dept of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China1
| | - Dianjun Cao
- Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China2
| | - Ningyi Jin
- Dept of Virus Research, University of Military Supplies, Changchun 130062, People's Republic of China3
| | - Catherine W-H Zhang
- Laboratory of Immunobiology, Dana-Farber Cancer Institute and Dept of Medicine, Harvard Medical School, Boston, MA 02115, USA4
| | - Mark Bartlam
- Laboratory of Structural Biology and MOE Laboratory of Protein Sciences, Tsinghua University, Beijing 100084, People's Republic of China5
| | - Zihe Rao
- Laboratory of Structural Biology and MOE Laboratory of Protein Sciences, Tsinghua University, Beijing 100084, People's Republic of China5
| | - Po Tien
- Dept of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China1
| | - George F Gao
- Laboratory of Molecular Medicine, Children's Hospital, Dept of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, and Dept of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA6
- Dept of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China1
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100
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Feldmann H, Volchkov VE, Volchkova VA, Ströher U, Klenk HD. Biosynthesis and role of filoviral glycoproteins. J Gen Virol 2001; 82:2839-2848. [PMID: 11714958 DOI: 10.1099/0022-1317-82-12-2839] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Heinz Feldmann
- Canadian Science Centre for Human and Animal Health, 1015 Arlington Street, Winnipeg, Manitoba, CanadaR3E 3R21
| | - Viktor E Volchkov
- Biologie des Filovirus, Claude Bernard University Lyon-1, 46 Allée d'Italie, 69007 Lyon, France2
| | - Valentina A Volchkova
- Biologie des Filovirus, Claude Bernard University Lyon-1, 46 Allée d'Italie, 69007 Lyon, France2
| | - Ute Ströher
- Institut für Virologie, Philipps-Universität, Robert-Koch-Str. 17, D-35037 Marburg, Germany3
| | - Hans-Dieter Klenk
- Institut für Virologie, Philipps-Universität, Robert-Koch-Str. 17, D-35037 Marburg, Germany3
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