title: Structural and functional studies of Stf76 from the Sulfolobus islandicus plasmid-virus pSSVx: a novel peculiar member of the winged helix-turn-helix transcription factor family.
abstract: The hybrid plasmid-virus pSSVx from Sulfolobus islandicus presents an open reading frame encoding a 76 amino acid protein, namely Stf76, that does not show significant sequence homology with any protein with known 3D structure. The recombinant protein recognizes specifically two DNA-binding sites located in its own promoter, thus suggesting an auto-regulated role of its expression. Circular dichroism, spectrofluorimetric, light scattering and isothermal titration calorimetry experiments indicated a 2:1 molar ratio (protein:DNA) upon binding to the DNA target containing a single site. Furthermore, the solution structure of Stf76, determined by nuclear magnetic resonance (NMR) using chemical shift Rosetta software, has shown that the protein assumes a winged helix-turn-helix fold. NMR chemical shift perturbation analysis has been performed for the identification of the residues responsible for DNA interaction. In addition, a model of the Stf76-DNA complex has been built using as template a structurally related homolog.
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Napoli "Federico II", Napoli 80126, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Contursi
authors.affiliation: Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy.
authors.forename: Biancamaria
authors.initials: B
authors.lastname: Farina
authors.affiliation: Istituto di Cristallografia, C.N.R., Bari 70126, Italy.
authors.forename: Luciano
authors.initials: L
authors.lastname: Pirone
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Napoli "Federico II", Napoli 80126, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Fusco
authors.affiliation: Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Caserta 81100, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Russo
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Napoli "Federico II", Napoli 80126, Italy.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Bartolucci
authors.affiliation: Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Seconda Università di Napoli, Caserta 81100, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Fattorusso
authors.affiliation: Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy Istituto di Biostrutture e Bioimmagini, C.N.R., Napoli 80134, Italy empedone@unina.it.
authors.forename: Emilia
authors.initials: E
authors.lastname: Pedone
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002942:Circular Dichroism; D019241:Fuselloviridae / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D012996:Solutions; D016944:Sulfolobus / Q000821:virology; D014764:Viral Proteins / Q000737:chemistry*; D051540:Winged-Helix Transcription Factors / Q000737:chemistry*
chemical_list: D012996:Solutions; D014764:Viral Proteins; D051540:Winged-Helix Transcription Factors