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David Prangishvili - One of the best experts on this subject based on the ideXlab platform.
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New archaeal viruses discovered by metagenomic analysis of viral communities in enrichment cultures.
Environmental microbiology, 2019Co-Authors: Ying Liu, Mart Krupovic, David Brandt, Sonoko Ishino, Yoshizumi Ishino, Eugene V. Koonin, Jörn Kalinowski, David PrangishviliAbstract:Viruses infecting hyperthermophilic archaea of the phylum Crenarchaeota display enormous morphological and genetic diversity, and are classified into 12 families. Eight of these families include only one or two species, indicating sparse sampling of the crenarchaeal virus diversity. In an attempt to expand the crenarchaeal virome, we explored virus diversity in the acidic, hot spring Umi Jigoku in Beppu, Japan. Environmental samples were used to establish enrichment cultures under conditions favouring virus replication. The host diversity in the enrichment cultures was restricted to members of the order Sulfolobales. Metagenomic sequencing of the viral communities yielded seven complete or near-complete double-stranded DNA virus genomes. Six of these genomes could be attributed to polyhedral and filamentous viruses that were observed by electron microscopy in the enrichment cultures. Two icosahedral viruses represented species in the family Portogloboviridae. Among the filamentous viruses, two were identified as new species in the families Rudiviridae and Lipothrixviridae, whereas two other formed a group seemingly distinct from the known virus genera. No particle morphotype could be unequivocally assigned to the seventh viral genome, which apparently represents a new virus type. Our results suggest that filamentous viruses are globally distributed and are prevalent virus types in extreme geothermal environments.
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a new proposed taxon for double stranded dna viruses the order ligamenvirales
Archives of Virology, 2012Co-Authors: David Prangishvili, Mart KrupovicAbstract:Linear viruses with double-stranded DNA genomes are classified into two families, Lipothrixviridae and Rudiviridae. The members of these two families, all of which infect hyperhermophilic members of the domain Archaea, differ significantly in the complexity of their virions as well as in their mechanisms of genome replication. However, recent structural and genomic studies have revealed a robust evolutionary link between members of the two families. To acknowledge this relationship we propose to unify the two families into the new taxonomic order “Ligamenvirales”.
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ORF157 from the Archaeal Virus Acidianus Filamentous Virus 1 Defines a New Class of Nuclease
Journal of virology, 2010Co-Authors: Adeline Goulet, Herman Van Tilbeurgh, Nicolas Leulliot, David Prangishvili, Peter Redder, Mery Pina, Laura Vera, Julie Lichière, Miguel Ortiz-lombardía, Valérie CampanacciAbstract:The properties of double-stranded DNA (dsDNA) viruses that infect Crenarchaea living in acidic hot springs (pH 1.5 to 3 and 75 to 95°C) are radically different from those of the viruses that infect Bacteria and Eukarya. Not only are the shapes of these viruses distinct from those of all other known viruses, but ∼80% of their open reading frames (ORFs) do not share any sequence similarity with ORFs of other viruses or of cellular life forms apart from other archaeal viruses (44). Seven novel viral families have been created to categorize their unique characteristics: the spindle-shaped Fuselloviridae, the filamentous Rudiviridae and Lipothrixviridae, the bottle-shaped Ampullaviridae, the droplet-shaped Guttaviridae, the spherical Globuloviridae, the two-tailed Bicaudaviridae, and the unclassified Sulfolobus turreted icosahedral virus (STIV) (43). The study of archaeal viruses is still in its infancy compared to that of eukaryal and bacterial viruses, and little is known regarding crenarchaeal virus life cycles, virus-host relationships, genetics, or biochemistry. Further studies of these viruses are expected to provide genetic, biochemical, and evolutionary insight into their crenarchaeal hosts and the requirements for life in the harsh environments. Transcription cycles of the fusellovirus Sulfolobus spindle-shaped virus 1 (SSV1) (16) and the rudiviruses Sulfolobus islandicus rod-shaped virus 1 and 2 (SIRV1 and SIRV2) (24) have been analyzed. Also, recent results concerning the lytic viruses STIV and SIRV2 shed new light on their replication cycle and interaction with their hosts (7, 9, 38). Because structures generally are much better conserved than sequences, structural studies have aimed at uncovering functional and evolutionary relationships that are not apparent from the primary sequence. To date, 11 protein structures from crenarchaeal viruses have been reported (18, 19, 22, 23, 25-30, 33). Most of these proteins share structural similarity with proteins of known function: three winged-helix proteins are likely involved in transcriptional regulation (two from the fusellovirus SSV1 [27, 33] and one from STIV [28]); one glycosyltransferase from STIV displays the GT-A fold (30); one adaptor protein from SSV1 is similar to the repressor of primer (ROP) of Escherichia coli (26); and the major coat protein of STIV has revealed the first evolutionary relationship spanning the three domains of life (25). The structures of the highly conserved ORFs among these viruses, ORF109 of lipothrixvirus AFV3 (22) and ORFB116 from STIV (29), suggest that they are DNA-binding proteins that function in transcriptional regulation. Filamentous viruses, the most abundant morphotype in these extreme environments, form the new viral order Ligamenvirales, which is divided into the Rudiviridae and Lipothrixviridae families (43). Lipothrixviruses (Acidianus filamentous virus 1 to 9, Thermoproteus tenax virus 1 to 3, and Sulfolobus islandicus filamentous virus) (8, 43), which were the first enveloped filamentous viruses with linear dsDNA genomes discovered, infect acidophilic and hyperthermophilic Crenarchaea. They are classified into α, β, γ, and δ genera based on their genomic properties and on the diversity of their terminal appendages, which are involved in host cell recognition. AFV1 is a γ-lipothrixvirus isolated from an acidic hot spring in Yellowstone National Park, where the temperature is above 85°C and the pH below 3 (6). The linear, double-stranded 20.8-kb DNA genome of AFV1 encodes 40 putative ORFs, 32% of which are homologous to viral ORFs from the lipothrixvirus SIFV and the rudiviruses SIRV1 and SIRV2. The predicted products generally are too dissimilar to the sequences in the public databases to allow functional assignment; only two glycosyltransferases, two CopG-like proteins, and one transcription regulator have been detected (6). It is highly unlikely that all of the encoded proteins consist entirely of unique protein folds serving novel functions. Therefore, to get insight into the biology of the Lipothrixviridae, we performed crystallographic studies of the AFV1 proteome. Although the solved structures of AFV1-102 (23) and the homologs AFV1-99 (19) and SIFV-014 (18) have not revealed any structural homologs, they have suggested that the proteins are involved in protein-protein interaction and are minor structural components, respectively. Here, we report the crystal structure of AFV1-157 and its biochemical characterization. AFV1-157 is a 157-residue protein with one homolog in the fusellovirus Sulfolobus spindle-shaped virus Ragged Hills (SSVRH). It has a novel α+β fold that remotely resembles the nucleotidyltransferase topology. We demonstrated that (i) AFV1-157 exhibits in vitro nuclease activity that degrades linear dsDNA, and (ii) the E86 residue is essential for the nuclease activity.
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Acidianus filamentous virus 1 coat proteins display a helical fold spanning the filamentous archaeal viruses lineage.
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Adeline Goulet, Stéphanie Blangy, David Prangishvili, Valérie Campanacci, Peter Redder, Catarina Felisberto-rodrigues, Patrick Forterre, Christian CambillauAbstract:Acidianus filamentous virus 1 (AFV1), a member of the Lipothrixviridae family, infects the hyperthermophilic, acidophilic crenarchaeaon Acidianus hospitalis. The virion, covered with a lipidic outer shell, is 9,100-A long and contains a 20.8-kb linear dsDNA genome. We have identified the two major coat proteins of the virion (MCPs; 132 and 140 amino acids). They bind DNA and form filaments when incubated with linear dsDNA. A C-terminal domain is identified in their crystal structure with a four-helix-bundle fold. In the topological model of the virion filament core, the genomic dsDNA superhelix wraps around the AFV1-132 basic protein, and the AFV1-140 basic N terminus binds genomic DNA, while its lipophilic C-terminal domain is imbedded in the lipidic outer shell. The four-helix bundle fold of the MCPs from AFV1 is identical to that of the coat protein (CP) of Sulfolobus islandicus rod-shaped virus (SIRV), a member of the Rudiviridae family. Despite low sequence identity between these proteins, their high degree of structural similarity suggests that they could have derived from a common ancestor and could thus define an yet undescribed viral lineage.
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The crystal structure of ORF14 from Sulfolobus islandicus filamentous virus.
Proteins, 2009Co-Authors: Adeline Goulet, Silvia Spinelli, Stéphanie Blangy, Herman Van Tilbeurgh, Nicolas Leulliot, Tamara Basta, David Prangishvili, Christian Cambillau, Valérie CampanacciAbstract:Studies on viruses in hot aquatic ecosystems, at temperatures above 808C, revealed unusual morphotypes and quasi-orphan genome sequences which made it possible to establish several new families of double-stranded (ds) DNA viruses. Among them, the Lipothrixviridae are enveloped lipid-containing filamentous viruses with linear double-stranded DNA genomes (AFV1-8, TTV1-3, and Sulfolobus islandicus filamentous virus [SIFV]).1–4 The hosts of these viruses are hyperthermophilic and hyperacidophilic archaea of the genera Acidianus or Sulfolobus. The 35 genomes of archaeal viruses that are presently sequenced have in common that more than 80% of their ORFs do not share any sequence homology with ORFs of other viruses or organisms apart from other archaeal viruses.4 Putative functions based on weak sequence identities have been proposed for a few ORFs, including structural proteins, glycosyl transerases, helicases, and integrases. Apart from structural proteins, it is expected that other ORFs should code for enzymes or proteins involved in viral infection and replication, and be functional homologues of bacterial, archaeal, or eukaryotic proteins. Moreover, they may reveal novel features which can be exploited for biotechnological applications. To get insight into the function of the Lipothrixviridae proteome, we have initiated a program to determine the structure of conserved ORFs. We present here the crystal structure of ORF14 of SIFV (Lipothrixviridae), a protein of 112 residues which has homologues in other archaeal viruses, Sulfolobus islandicus rod-shaped virus 1 (SIRV1, Rudiviridae; ORF99, ORF100, ORF95, and ORF96) and Acidianus filamentous virus 1 (AFV1, Lipothrixviridae; ORF99) [Fig. 1(A)]. SIFV-14 has a domain swapped structure and forms fiber structures in the crystal.
Valérie Campanacci - One of the best experts on this subject based on the ideXlab platform.
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ORF157 from the Archaeal Virus Acidianus Filamentous Virus 1 Defines a New Class of Nuclease
Journal of virology, 2010Co-Authors: Adeline Goulet, Herman Van Tilbeurgh, Nicolas Leulliot, David Prangishvili, Peter Redder, Mery Pina, Laura Vera, Julie Lichière, Miguel Ortiz-lombardía, Valérie CampanacciAbstract:The properties of double-stranded DNA (dsDNA) viruses that infect Crenarchaea living in acidic hot springs (pH 1.5 to 3 and 75 to 95°C) are radically different from those of the viruses that infect Bacteria and Eukarya. Not only are the shapes of these viruses distinct from those of all other known viruses, but ∼80% of their open reading frames (ORFs) do not share any sequence similarity with ORFs of other viruses or of cellular life forms apart from other archaeal viruses (44). Seven novel viral families have been created to categorize their unique characteristics: the spindle-shaped Fuselloviridae, the filamentous Rudiviridae and Lipothrixviridae, the bottle-shaped Ampullaviridae, the droplet-shaped Guttaviridae, the spherical Globuloviridae, the two-tailed Bicaudaviridae, and the unclassified Sulfolobus turreted icosahedral virus (STIV) (43). The study of archaeal viruses is still in its infancy compared to that of eukaryal and bacterial viruses, and little is known regarding crenarchaeal virus life cycles, virus-host relationships, genetics, or biochemistry. Further studies of these viruses are expected to provide genetic, biochemical, and evolutionary insight into their crenarchaeal hosts and the requirements for life in the harsh environments. Transcription cycles of the fusellovirus Sulfolobus spindle-shaped virus 1 (SSV1) (16) and the rudiviruses Sulfolobus islandicus rod-shaped virus 1 and 2 (SIRV1 and SIRV2) (24) have been analyzed. Also, recent results concerning the lytic viruses STIV and SIRV2 shed new light on their replication cycle and interaction with their hosts (7, 9, 38). Because structures generally are much better conserved than sequences, structural studies have aimed at uncovering functional and evolutionary relationships that are not apparent from the primary sequence. To date, 11 protein structures from crenarchaeal viruses have been reported (18, 19, 22, 23, 25-30, 33). Most of these proteins share structural similarity with proteins of known function: three winged-helix proteins are likely involved in transcriptional regulation (two from the fusellovirus SSV1 [27, 33] and one from STIV [28]); one glycosyltransferase from STIV displays the GT-A fold (30); one adaptor protein from SSV1 is similar to the repressor of primer (ROP) of Escherichia coli (26); and the major coat protein of STIV has revealed the first evolutionary relationship spanning the three domains of life (25). The structures of the highly conserved ORFs among these viruses, ORF109 of lipothrixvirus AFV3 (22) and ORFB116 from STIV (29), suggest that they are DNA-binding proteins that function in transcriptional regulation. Filamentous viruses, the most abundant morphotype in these extreme environments, form the new viral order Ligamenvirales, which is divided into the Rudiviridae and Lipothrixviridae families (43). Lipothrixviruses (Acidianus filamentous virus 1 to 9, Thermoproteus tenax virus 1 to 3, and Sulfolobus islandicus filamentous virus) (8, 43), which were the first enveloped filamentous viruses with linear dsDNA genomes discovered, infect acidophilic and hyperthermophilic Crenarchaea. They are classified into α, β, γ, and δ genera based on their genomic properties and on the diversity of their terminal appendages, which are involved in host cell recognition. AFV1 is a γ-lipothrixvirus isolated from an acidic hot spring in Yellowstone National Park, where the temperature is above 85°C and the pH below 3 (6). The linear, double-stranded 20.8-kb DNA genome of AFV1 encodes 40 putative ORFs, 32% of which are homologous to viral ORFs from the lipothrixvirus SIFV and the rudiviruses SIRV1 and SIRV2. The predicted products generally are too dissimilar to the sequences in the public databases to allow functional assignment; only two glycosyltransferases, two CopG-like proteins, and one transcription regulator have been detected (6). It is highly unlikely that all of the encoded proteins consist entirely of unique protein folds serving novel functions. Therefore, to get insight into the biology of the Lipothrixviridae, we performed crystallographic studies of the AFV1 proteome. Although the solved structures of AFV1-102 (23) and the homologs AFV1-99 (19) and SIFV-014 (18) have not revealed any structural homologs, they have suggested that the proteins are involved in protein-protein interaction and are minor structural components, respectively. Here, we report the crystal structure of AFV1-157 and its biochemical characterization. AFV1-157 is a 157-residue protein with one homolog in the fusellovirus Sulfolobus spindle-shaped virus Ragged Hills (SSVRH). It has a novel α+β fold that remotely resembles the nucleotidyltransferase topology. We demonstrated that (i) AFV1-157 exhibits in vitro nuclease activity that degrades linear dsDNA, and (ii) the E86 residue is essential for the nuclease activity.
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Acidianus filamentous virus 1 coat proteins display a helical fold spanning the filamentous archaeal viruses lineage.
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Adeline Goulet, Stéphanie Blangy, David Prangishvili, Valérie Campanacci, Peter Redder, Catarina Felisberto-rodrigues, Patrick Forterre, Christian CambillauAbstract:Acidianus filamentous virus 1 (AFV1), a member of the Lipothrixviridae family, infects the hyperthermophilic, acidophilic crenarchaeaon Acidianus hospitalis. The virion, covered with a lipidic outer shell, is 9,100-A long and contains a 20.8-kb linear dsDNA genome. We have identified the two major coat proteins of the virion (MCPs; 132 and 140 amino acids). They bind DNA and form filaments when incubated with linear dsDNA. A C-terminal domain is identified in their crystal structure with a four-helix-bundle fold. In the topological model of the virion filament core, the genomic dsDNA superhelix wraps around the AFV1-132 basic protein, and the AFV1-140 basic N terminus binds genomic DNA, while its lipophilic C-terminal domain is imbedded in the lipidic outer shell. The four-helix bundle fold of the MCPs from AFV1 is identical to that of the coat protein (CP) of Sulfolobus islandicus rod-shaped virus (SIRV), a member of the Rudiviridae family. Despite low sequence identity between these proteins, their high degree of structural similarity suggests that they could have derived from a common ancestor and could thus define an yet undescribed viral lineage.
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The crystal structure of ORF14 from Sulfolobus islandicus filamentous virus.
Proteins, 2009Co-Authors: Adeline Goulet, Silvia Spinelli, Stéphanie Blangy, Herman Van Tilbeurgh, Nicolas Leulliot, Tamara Basta, David Prangishvili, Christian Cambillau, Valérie CampanacciAbstract:Studies on viruses in hot aquatic ecosystems, at temperatures above 808C, revealed unusual morphotypes and quasi-orphan genome sequences which made it possible to establish several new families of double-stranded (ds) DNA viruses. Among them, the Lipothrixviridae are enveloped lipid-containing filamentous viruses with linear double-stranded DNA genomes (AFV1-8, TTV1-3, and Sulfolobus islandicus filamentous virus [SIFV]).1–4 The hosts of these viruses are hyperthermophilic and hyperacidophilic archaea of the genera Acidianus or Sulfolobus. The 35 genomes of archaeal viruses that are presently sequenced have in common that more than 80% of their ORFs do not share any sequence homology with ORFs of other viruses or organisms apart from other archaeal viruses.4 Putative functions based on weak sequence identities have been proposed for a few ORFs, including structural proteins, glycosyl transerases, helicases, and integrases. Apart from structural proteins, it is expected that other ORFs should code for enzymes or proteins involved in viral infection and replication, and be functional homologues of bacterial, archaeal, or eukaryotic proteins. Moreover, they may reveal novel features which can be exploited for biotechnological applications. To get insight into the function of the Lipothrixviridae proteome, we have initiated a program to determine the structure of conserved ORFs. We present here the crystal structure of ORF14 of SIFV (Lipothrixviridae), a protein of 112 residues which has homologues in other archaeal viruses, Sulfolobus islandicus rod-shaped virus 1 (SIRV1, Rudiviridae; ORF99, ORF100, ORF95, and ORF96) and Acidianus filamentous virus 1 (AFV1, Lipothrixviridae; ORF99) [Fig. 1(A)]. SIFV-14 has a domain swapped structure and forms fiber structures in the crystal.
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The thermo‐ and acido‐stable ORF‐99 from the archaeal virus AFV1
Protein science : a publication of the Protein Society, 2009Co-Authors: Adeline Goulet, Silvia Spinelli, Stéphanie Blangy, Herman Van Tilbeurgh, Nicolas Leulliot, Tamara Basta, David Prangishvili, Christian Cambillau, Valérie CampanacciAbstract:Acidianus Filamentous Virus 1 (AFV1), isolated from acidic hot springs, is an enveloped lipid-containing archaeal filamentous virus with a linear double-stranded DNA genome. It infects Acidianus, which is a hyperthermostable archaea growing at 85°C and acidic pHs, below pH 3. AFV1-99, a protein of 99 amino acids of unknown function, has homologues in the archaeal virus families Lipothrixviridae and Rudiviridae. We determined the crystal structure of AFV1-99 at 2.05 A resolution. AFV1-99 has a new fold, is hyperthermostable (up to 95°C) and resists to extreme pH (between pH 0 and 11) and to the combination of high temperature (95°C) and low pH (pH 0). It possesses characteristics of hyperthermostable proteins, such as a high content of charged residues.
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Crystal structure of AFV3-109, a highly conserved protein from crenarchaeal viruses
Virology Journal, 2007Co-Authors: Jenny Keller, Nicolas Leulliot, David Prangishvili, Christian Cambillau, Valérie Campanacci, Patrick Forterre, Stéphanie Porciero, Diego Cortez, Sophie Quevillon-cheruel, Herman Van TilbeurghAbstract:The extraordinary morphologies of viruses infecting hyperthermophilic archaea clearly distinguish them from bacterial and eukaryotic viruses. Moreover, their genomes code for proteins that to a large extend have no related sequences in the extent databases. However, a small pool of genes is shared by overlapping subsets of these viruses, and the most conserved gene, exemplified by the ORF109 of the Acidianus Filamentous Virus 3, AFV3, is present on genomes of members of three viral familes, the Lipothrixviridae, Rudiviridae , and "Bicaudaviridae" , as well as of the unclassified Sulfolobus Turreted Icosahedral Virus, STIV. We present here the crystal structure of the protein (Mr = 13.1 kD, 109 residues) encoded by the AFV3 ORF 109 in two different crystal forms at 1.5 and 1.3 Å resolution. The structure of AFV3-109 is a five stranded β-sheet with loops on one side and three helices on the other. It forms a dimer adopting the shape of a cradle that encompasses the best conserved regions of the sequence. No protein with a related fold could be identified except for the ortholog from STIV1, whose structure was deposited at the Protein Data Bank. We could clearly identify a well bound glycerol inside the cradle, contacting exclusively totally conserved residues. This interaction was confirmed in solution by fluorescence titration. Although the function of AFV3-109 cannot be deduced directly from its structure, structural homology with the STIV1 protein, and the size and charge distribution of the cavity suggested it could interact with nucleic acids. Fluorescence quenching titrations also showed that AFV3-109 interacts with dsDNA. Genomic sequence analysis revealed bacterial homologs of AFV3-109 as a part of a putative previously unidentified prophage sequences in some Firmicutes.
Roger A. Garrett - One of the best experts on this subject based on the ideXlab platform.
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Structure of the Acidianus Filamentous Virus 3 and Comparative Genomics of Related Archaeal Lipothrixviruses
Journal of Virology, 2008Co-Authors: Gisle Vestergaard, Tamara Basta, Xu Peng, R. Rachel, M. Häring, Ricardo Aramayo, Kim Brügger, Lanming Chen, Nicolas Boisset, Roger A. GarrettAbstract:Four novel filamentous viruses with double-stranded DNA genomes, namely, Acidianus filamentous virus 3 (AFV3), AFV6, AFV7, and AFV8, have been characterized from the hyperthermophilic archaeal genus Acidi- anus, and they are assigned to the Betalipothrixvirus genus of the family Lipothrixviridae. The structures of the approximately 2-m-long virions are similar, and one of them, AFV3, was studied in detail. It consists of a cylindrical envelope containing globular subunits arranged in a helical formation that is unique for any known double-stranded DNA virus. The envelope is 3.1 nm thick and encases an inner core with two parallel rows of protein subunits arranged like a zipper. Each end of the virion is tapered and carries three short filaments. Two major structural proteins were identified as being common to all betalipothrixviruses. The viral genomes were sequenced and analyzed, and they reveal a high level of conservation in both gene content and gene order over large regions, with this similarity extending partly to the earlier described betalipothrixvirus Sulfolobus islandicus filamentous virus. A few predicted gene products of each virus, in addition to the structural proteins, could be assigned specific functions, including a putative helicase involved in Holliday junction branch migration, a nuclease, a protein phosphatase, transcriptional regulators, and glycosyltransferases. The AFV7 genome appears to have undergone intergenomic recombination with a large section of an AFV2-like viral genome, apparently resulting in phenotypic changes, as revealed by the presence of AFV2-like termini in the AFV7 virions. Shared features of the genomes include (i) large inverted terminal repeats exhibiting conserved, regularly spaced direct repeats; (ii) a highly conserved operon encoding the two major structural proteins; (iii) multiple overlapping open reading frames, which may be indicative of gene recoding; (iv) putative 12-bp genetic elements; and (v) partial gene sequences corresponding closely to spacer sequences of chromosomal repeat clusters.
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Structure of the Acidianus Filamentous Virus 3 and Comparative Genomics of Related Archaeal Lipothrixviruses �
2007Co-Authors: Gisle Vestergaard, Tamara Basta, Xu Peng, R. Rachel, M. Häring, Ricardo Aramayo, Kim Brügger, Lanming Chen, Nicolas Boisset, Roger A. GarrettAbstract:Four novel filamentous viruses with double-stranded DNA genomes, namely, Acidianus filamentous virus 3 (AFV3), AFV6, AFV7, and AFV8, have been characterized from the hyperthermophilic archaeal genus Acidianus, and they are assigned to the Betalipothrixvirus genus of the family Lipothrixviridae. The structures of the approximately 2-�m-long virions are similar, and one of them, AFV3, was studied in detail. It consists of a cylindrical envelope containing globular subunits arranged in a helical formation that is unique for any known double-stranded DNA virus. The envelope is 3.1 nm thick and encases an inner core with two parallel rows of protein subunits arranged like a zipper. Each end of the virion is tapered and carries three short filaments. Two major structural proteins were identified as being common to all betalipothrixviruses. The viral genomes were sequenced and analyzed, and they reveal a high level of conservation in both gene content and gene order over large regions, with this similarity extending partly to the earlier described betalipothrixvirus Sulfolobus islandicus filamentous virus. A few predicted gene products of each virus, in addition to the structural proteins, could be assigned specific functions, including a putative helicase involved in Holliday junction branc
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Exceptionally diverse morphotypes and genomes of crenarchaeal hyperthermophilic viruses.
Biochemical Society Transactions, 2004Co-Authors: David Prangishvili, Roger A. GarrettAbstract:The remarkable diversity of the morphologies of viruses found in terrestrial hydrothermal environments with temperatures >80 ◦ C is unprecedented for aquatic ecosystems. The best-studied viruses from these habitats have been assigned to novel viral families : Fuselloviridae, Lipothrixviridae and Rudiviridae. They all have double-stranded DNA genomes and infect hyperthermophilic crenarchaea of the orders Sulfolobales and Thermoproteales. Representatives of the different viral families share a few homologous ORFs (open reading frames). However, about 90% of all ORFs in the seven sequenced genomes show no significant matches to sequences in public databases. This suggests that these hyperthermophilic viruses have exceptional biochemical solutions for biological functions. Specific features of genome organization, as well as strategies for DNA replication, suggest that phylogenetic relationships exist between crenarchaeal rudiviruses and the large eukaryal DNA viruses : poxviruses, the African swine fever virus and Chlorella viruses. Sequence patterns at the ends of the linear genome of the lipothrixvirus AFV1 are reminiscent of the telomeric ends of linear eukaryal chromosomes and suggest that a primitive telomeric mechanism operates in this virus.
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AFV1, a novel virus infecting hyperthermophilic archaea of the genus acidianus.
Virology, 2003Co-Authors: M. Bettstetter, Xu Peng, Roger A. Garrett, David PrangishviliAbstract:Abstract We describe a novel virus, AFV1, of the hyperthermophilic archaeal genus Acidianus. Filamentous virions are covered with a lipid envelope and contain at least five different proteins with molecular masses in the range of 23–130 kDa and a 20.8-kb-long linear double-stranded DNA. The virus has been assigned to the family Lipothrixviridae on the basis of morphotypic characteristics. Host range is confined to several strains of Acidianus and the virus persists in its hosts in a stable carrier state. The latent period of virus infection is about 4 h. Viral DNA was sequenced and sequence similarities were found to the lipothrixvirus SIFV, the rudiviruses SIRV1 and SIRV2, as well as to conjugative plasmids and chromosomes of the genus Sulfolobus. Exceptionally for the linear genomes of archaeal viruses, many short direct repeats, with the sequence TTGTT or close variants thereof, are closely clustered over 300 bp at each end of the genome. They are reminiscent of the telomeric ends of linear eukaryal chromosomes.
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Sequences and replication of genomes of the archaeal rudiviruses SIRV1 and SIRV2: relationships to the archaeal lipothrixvirus SIFV and some eukaryal viruses.
Virology, 2001Co-Authors: Xu Peng, Roger A. Garrett, Kim Brügger, Helmut Blum, Qunxin She, S. Mallok, Wolfram Zillig, David PrangishviliAbstract:The double-stranded DNA genomes of the viruses SIRV1 and SIRV2, which infect the extremely thermophilic archaeon Sulfolobus and belong to the family Rudiviridae, were sequenced. They are linear, covalently closed at the ends, and 32,312 and 35,502 bp long, respectively, with an A+T content of 75%. The genomes of SIRV1 and SIRV2 carry inverted terminal repeats of 2029 and 1628 bp, respectively, which contain multiple direct repeats. SIRV1 and SIRV2 genomes contain 45 and 54 ORFs, respectively, of which 44 are homologous to one another. Their predicted functions include a DNA polymerase, a Holliday junction resolvase, and a dUTPase. The genomes consist of blocks with well-conserved sequences separated by nonconserved sequences. Recombination, gene duplication, horizontal gene transfer, and substitution of viral genes by homologous host genes have contributed to their evolution. The finding of head-to-head and tail-to-tail linked replicative intermediates suggests that the linear genomes replicate by the same mechanism as the similarly organized linear genomes of the eukaryal poxviruses, African swine fever virus and Chlorella viruses. SIRV1 and SIRV2 both contain motifs that resemble the binding sites for Holliday junction resolvases of eukaryal viruses and may use common mechanisms for resolution of replicative intermediates. The results suggest a common origin of the replication machineries of the archaeal rudiviruses and the above-mentioned eukaryal viruses. About 1/3 of the ORFs of each rudivirus have homologs in the Sulfolobus virus SIFV of the family Lipothrixviridae, indicating that the two viral families form a superfamily. The finding of inverted repeats of at least 0.8 kb at the termini of the linear genome of SIFV supports this inference.
Xu Peng - One of the best experts on this subject based on the ideXlab platform.
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Novel viral genomes identified from six metagenomes reveal wide distribution of archaeal viruses and high viral diversity in terrestrial hot springs
Environmental microbiology, 2015Co-Authors: Soley Gudbergsdottir, Peter Menzel, Anders Krogh, Mark J. Young, Xu PengAbstract:Limited by culture-dependent methods the number of viruses identified from thermophilic Archaea and Bacteria is still very small. In this study we retrieved viral sequences from six hot spring metagenomes isolated worldwide, revealing a wide distribution of four archaeal viral families, Ampullaviridae, Bicaudaviridae, Lipothrixviridae and Rudiviridae. Importantly, we identified 10 complete or near complete viral genomes allowing, for the first time, an assessment of genome conservation and evolution of the Ampullaviridae family as well as Sulfolobus Monocaudavirus 1 (SMV1)-related viruses. Among the novel genomes, one belongs to a putative thermophilic virus infecting the bacterium Hydrogenobaculum, for which no virus has been reported in the literature. Moreover, a high viral diversity was observed in the metagenomes, especially among the Lipothrixviridae, as indicated by the large number of unique contigs and the lack of a completely assembled genome for this family. This is further supported by the large number of novel genes in the complete and partial genomes showing no sequence similarities to public databases. CRISPR analysis revealed hundreds of novel CRISPR loci and thousands of novel CRISPR spacers from each metagenome, reinforcing the notion of high viral diversity in the thermal environment.
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Structure of the Acidianus Filamentous Virus 3 and Comparative Genomics of Related Archaeal Lipothrixviruses
Journal of Virology, 2008Co-Authors: Gisle Vestergaard, Tamara Basta, Xu Peng, R. Rachel, M. Häring, Ricardo Aramayo, Kim Brügger, Lanming Chen, Nicolas Boisset, Roger A. GarrettAbstract:Four novel filamentous viruses with double-stranded DNA genomes, namely, Acidianus filamentous virus 3 (AFV3), AFV6, AFV7, and AFV8, have been characterized from the hyperthermophilic archaeal genus Acidi- anus, and they are assigned to the Betalipothrixvirus genus of the family Lipothrixviridae. The structures of the approximately 2-m-long virions are similar, and one of them, AFV3, was studied in detail. It consists of a cylindrical envelope containing globular subunits arranged in a helical formation that is unique for any known double-stranded DNA virus. The envelope is 3.1 nm thick and encases an inner core with two parallel rows of protein subunits arranged like a zipper. Each end of the virion is tapered and carries three short filaments. Two major structural proteins were identified as being common to all betalipothrixviruses. The viral genomes were sequenced and analyzed, and they reveal a high level of conservation in both gene content and gene order over large regions, with this similarity extending partly to the earlier described betalipothrixvirus Sulfolobus islandicus filamentous virus. A few predicted gene products of each virus, in addition to the structural proteins, could be assigned specific functions, including a putative helicase involved in Holliday junction branch migration, a nuclease, a protein phosphatase, transcriptional regulators, and glycosyltransferases. The AFV7 genome appears to have undergone intergenomic recombination with a large section of an AFV2-like viral genome, apparently resulting in phenotypic changes, as revealed by the presence of AFV2-like termini in the AFV7 virions. Shared features of the genomes include (i) large inverted terminal repeats exhibiting conserved, regularly spaced direct repeats; (ii) a highly conserved operon encoding the two major structural proteins; (iii) multiple overlapping open reading frames, which may be indicative of gene recoding; (iv) putative 12-bp genetic elements; and (v) partial gene sequences corresponding closely to spacer sequences of chromosomal repeat clusters.
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Structure of the Acidianus Filamentous Virus 3 and Comparative Genomics of Related Archaeal Lipothrixviruses
'American Society for Microbiology', 2008Co-Authors: Vestergaard Gisle, Xu Peng, Basta Tamara, Aramayo Ricardo, Haring Monika, Brugger Kim, Chen Lanming, Rachel Reinhard, Boisset Nicolas, Garrett, Roger A.Abstract:International audienceFour novel filamentous viruses with double-stranded DNA genomes, namely, Acidianus filamentous virus 3 (AFV3), AFV6, AFV7, and AFV8, have been characterized from the hyperthermophilic archaeal genus Acidi- anus, and they are assigned to the Betalipothrixvirus genus of the family Lipothrixviridae. The structures of the approximately 2-m-long virions are similar, and one of them, AFV3, was studied in detail. It consists of a cylindrical envelope containing globular subunits arranged in a helical formation that is unique for any known double-stranded DNA virus. The envelope is 3.1 nm thick and encases an inner core with two parallel rows of protein subunits arranged like a zipper. Each end of the virion is tapered and carries three short filaments. Two major structural proteins were identified as being common to all betalipothrixviruses. The viral genomes were sequenced and analyzed, and they reveal a high level of conservation in both gene content and gene order over large regions, with this similarity extending partly to the earlier described betalipothrixvirus Sulfolobus islandicus filamentous virus. A few predicted gene products of each virus, in addition to the structural proteins, could be assigned specific functions, including a putative helicase involved in Holliday junction branch migration, a nuclease, a protein phosphatase, transcriptional regulators, and glycosyltransferases. The AFV7 genome appears to have undergone intergenomic recombination with a large section of an AFV2-like viral genome, apparently resulting in phenotypic changes, as revealed by the presence of AFV2-like termini in the AFV7 virions. Shared features of the genomes include (i) large inverted terminal repeats exhibiting conserved, regularly spaced direct repeats; (ii) a highly conserved operon encoding the two major structural proteins; (iii) multiple overlapping open reading frames, which may be indicative of gene recoding; (iv) putative 12-bp genetic elements; and (v) partial gene sequences corresponding closely to spacer sequences of chromosomal repeat clusters
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Structure of the Acidianus Filamentous Virus 3 and Comparative Genomics of Related Archaeal Lipothrixviruses �
2007Co-Authors: Gisle Vestergaard, Tamara Basta, Xu Peng, R. Rachel, M. Häring, Ricardo Aramayo, Kim Brügger, Lanming Chen, Nicolas Boisset, Roger A. GarrettAbstract:Four novel filamentous viruses with double-stranded DNA genomes, namely, Acidianus filamentous virus 3 (AFV3), AFV6, AFV7, and AFV8, have been characterized from the hyperthermophilic archaeal genus Acidianus, and they are assigned to the Betalipothrixvirus genus of the family Lipothrixviridae. The structures of the approximately 2-�m-long virions are similar, and one of them, AFV3, was studied in detail. It consists of a cylindrical envelope containing globular subunits arranged in a helical formation that is unique for any known double-stranded DNA virus. The envelope is 3.1 nm thick and encases an inner core with two parallel rows of protein subunits arranged like a zipper. Each end of the virion is tapered and carries three short filaments. Two major structural proteins were identified as being common to all betalipothrixviruses. The viral genomes were sequenced and analyzed, and they reveal a high level of conservation in both gene content and gene order over large regions, with this similarity extending partly to the earlier described betalipothrixvirus Sulfolobus islandicus filamentous virus. A few predicted gene products of each virus, in addition to the structural proteins, could be assigned specific functions, including a putative helicase involved in Holliday junction branc
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AFV1, a novel virus infecting hyperthermophilic archaea of the genus acidianus.
Virology, 2003Co-Authors: M. Bettstetter, Xu Peng, Roger A. Garrett, David PrangishviliAbstract:Abstract We describe a novel virus, AFV1, of the hyperthermophilic archaeal genus Acidianus. Filamentous virions are covered with a lipid envelope and contain at least five different proteins with molecular masses in the range of 23–130 kDa and a 20.8-kb-long linear double-stranded DNA. The virus has been assigned to the family Lipothrixviridae on the basis of morphotypic characteristics. Host range is confined to several strains of Acidianus and the virus persists in its hosts in a stable carrier state. The latent period of virus infection is about 4 h. Viral DNA was sequenced and sequence similarities were found to the lipothrixvirus SIFV, the rudiviruses SIRV1 and SIRV2, as well as to conjugative plasmids and chromosomes of the genus Sulfolobus. Exceptionally for the linear genomes of archaeal viruses, many short direct repeats, with the sequence TTGTT or close variants thereof, are closely clustered over 300 bp at each end of the genome. They are reminiscent of the telomeric ends of linear eukaryal chromosomes.
Eugene V. Koonin - One of the best experts on this subject based on the ideXlab platform.
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New archaeal viruses discovered by metagenomic analysis of viral communities in enrichment cultures.
Environmental microbiology, 2019Co-Authors: Ying Liu, Mart Krupovic, David Brandt, Sonoko Ishino, Yoshizumi Ishino, Eugene V. Koonin, Jörn Kalinowski, David PrangishviliAbstract:Viruses infecting hyperthermophilic archaea of the phylum Crenarchaeota display enormous morphological and genetic diversity, and are classified into 12 families. Eight of these families include only one or two species, indicating sparse sampling of the crenarchaeal virus diversity. In an attempt to expand the crenarchaeal virome, we explored virus diversity in the acidic, hot spring Umi Jigoku in Beppu, Japan. Environmental samples were used to establish enrichment cultures under conditions favouring virus replication. The host diversity in the enrichment cultures was restricted to members of the order Sulfolobales. Metagenomic sequencing of the viral communities yielded seven complete or near-complete double-stranded DNA virus genomes. Six of these genomes could be attributed to polyhedral and filamentous viruses that were observed by electron microscopy in the enrichment cultures. Two icosahedral viruses represented species in the family Portogloboviridae. Among the filamentous viruses, two were identified as new species in the families Rudiviridae and Lipothrixviridae, whereas two other formed a group seemingly distinct from the known virus genera. No particle morphotype could be unequivocally assigned to the seventh viral genome, which apparently represents a new virus type. Our results suggest that filamentous viruses are globally distributed and are prevalent virus types in extreme geothermal environments.
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A census of α-helical membrane proteins in double-stranded DNA viruses infecting bacteria and archaea
BMC Bioinformatics, 2015Co-Authors: David M. Kristensen, Usman Saeed, Dmitrij Frishman, Eugene V. KooninAbstract:Background Viruses are the most abundant and genetically diverse biological entities on earth, yet the repertoire of viral proteins remains poorly explored. As the number of sequenced virus genomes grows into the thousands, and the number of viral proteins into the hundreds of thousands, we report a systematic computational analysis of the point of first-contact between viruses and their hosts, namely viral transmembrane (TM) proteins. Results The complement of α-helical TM proteins in double-stranded DNA viruses infecting bacteria and archaea reveals large-scale trends that differ from those of their hosts. Viruses typically encode a substantially lower fraction of TM proteins than archaea or bacteria, with the notable exception of viruses with virions containing a lipid component such as a lipid envelope, internal lipid core, or inner membrane vesicle. Compared to bacteriophages, archaeal viruses are substantially enriched in membrane proteins. However, this feature is not always stable throughout the evolution of a viral lineage; for example, TM proteins are not part of the common heritage shared between Lipothrixviridae and Rudiviridae. In contrast to bacteria and archaea, viruses almost completely lack proteins with complicated membrane topologies composed of more than 4 TM segments, with the few detected exceptions being obvious cases of relatively recent horizontal transfer from the host. Conclusions The dramatic differences between the membrane proteomes of cells and viruses stem from the fact that viruses do not depend on essential membranes for energy transformation, ion homeostasis, nutrient transport and signaling.
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a census of α helical membrane proteins in double stranded dna viruses infecting bacteria and archaea
BMC Bioinformatics, 2015Co-Authors: Usman Saeed, David M. Kristensen, Dmitrij Frishman, Eugene V. KooninAbstract:Viruses are the most abundant and genetically diverse biological entities on earth, yet the repertoire of viral proteins remains poorly explored. As the number of sequenced virus genomes grows into the thousands, and the number of viral proteins into the hundreds of thousands, we report a systematic computational analysis of the point of first-contact between viruses and their hosts, namely viral transmembrane (TM) proteins. The complement of α-helical TM proteins in double-stranded DNA viruses infecting bacteria and archaea reveals large-scale trends that differ from those of their hosts. Viruses typically encode a substantially lower fraction of TM proteins than archaea or bacteria, with the notable exception of viruses with virions containing a lipid component such as a lipid envelope, internal lipid core, or inner membrane vesicle. Compared to bacteriophages, archaeal viruses are substantially enriched in membrane proteins. However, this feature is not always stable throughout the evolution of a viral lineage; for example, TM proteins are not part of the common heritage shared between Lipothrixviridae and Rudiviridae. In contrast to bacteria and archaea, viruses almost completely lack proteins with complicated membrane topologies composed of more than 4 TM segments, with the few detected exceptions being obvious cases of relatively recent horizontal transfer from the host. The dramatic differences between the membrane proteomes of cells and viruses stem from the fact that viruses do not depend on essential membranes for energy transformation, ion homeostasis, nutrient transport and signaling.