title: Structure, function, and targets of the transcriptional regulator SvtR from the hyperthermophilic archaeal virus SIRV1.
abstract: We have characterized the structure and the function of the 6.6-kDa protein SvtR (formerly called gp08) from the rod-shaped virus SIRV1, which infects the hyperthermophilic archaeon Sulfolobus islandicus that thrives at 85 degrees C in hot acidic springs. The protein forms a dimer in solution. The NMR solution structure of the protein consists of a ribbon-helix-helix (RHH) fold between residues 13 and 56 and a disordered N-terminal region (residues 1-12). The structure is very similar to that of bacterial RHH proteins despite the low sequence similarity. We demonstrated that the protein binds DNA and uses its beta-sheet face for the interaction like bacterial RHH proteins. To detect all the binding sites on the 32.3-kb SIRV1 linear genome, we designed and performed a global genome-wide search of targets based on a simplified electrophoretic mobility shift assay. Four targets were recognized by the protein. The strongest binding was observed with the promoter of the gene coding for a virion structural protein. When assayed in a host reconstituted in vitro transcription system, the protein SvtR (Sulfolobus virus transcription regulator) repressed transcription from the latter promoter, as well as from the promoter of its own gene.
authors.affiliation: Institut Pasteur, Unité de RMN des Biomolécules, CNRS URA 2185, 75015 Paris.
authors.forename: Florence
authors.initials: F
authors.lastname: Guillière
authors.affiliation: Institut Pasteur, Unité de Biologie Moléculaire du Gène chez les Extrêmophiles, 75015 Paris.
authors.forename: Nuno
authors.initials: N
authors.lastname: Peixeiro
authors.affiliation: Institut Pasteur, Unité de Biologie Moléculaire du Gène chez les Extrêmophiles, 75015 Paris.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kessler
authors.affiliation: Institut Pasteur, Plate-forme de Biophysique des Macromolécules et de leurs Interactions, 75015 Paris.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Raynal
authors.affiliation: Institut Pasteur, Unité de Biologie Moléculaire du Gène chez les Extrêmophiles, 75015 Paris.
authors.forename: Nicole
authors.initials: N
authors.lastname: Desnoues
authors.affiliation: Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, CNRS-UMR 8619, Université Paris 11, IFR115, Bâtiment 430, 91405 Orsay.
authors.forename: Jenny
authors.initials: J
authors.lastname: Keller
authors.affiliation: Institut Pasteur, Unité de RMN des Biomolécules, CNRS URA 2185, 75015 Paris.
authors.forename: Muriel
authors.initials: M
authors.lastname: Delepierre
authors.affiliation: Institut Pasteur, Unité de Biologie Moléculaire du Gène chez les Extrêmophiles, 75015 Paris.
authors.forename: David
authors.initials: D
authors.lastname: Prangishvili
authors.affiliation: Institut Pasteur, Unité de Biologie Moléculaire du Gène chez les Extrêmophiles, 75015 Paris; Université Pierre et Marie Curie, 4 place Jussieu, 75005 Paris, France.
authors.forename: Guennadi
authors.initials: G
authors.lastname: Sezonov
authors.affiliation: Institut Pasteur, Unité de RMN des Biomolécules, CNRS URA 2185, 75015 Paris.
authors.forename: J Iñaki
authors.initials: JI
authors.lastname: Guijarro
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D019281:Dimerization; D015967:Gene Expression Regulation, Viral; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017433:Protein Structure, Secondary; D023642:Rudiviridae / Q000378:metabolism*; D013329:Structure-Activity Relationship; D016944:Sulfolobus / Q000821:virology*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000737:chemistry*
chemical_list: D014764:Viral Proteins