title: The archaeal "7 kDa DNA-binding" proteins: extended characterization of an old gifted family.
abstract: The "7 kDa DNA-binding" family, also known as the Sul7d family, is composed of chromatin proteins from the Sulfolobales archaeal order. Among them, Sac7d and Sso7d have been the focus of several studies with some characterization of their properties. Here, we studied eleven other proteins alongside Sac7d and Sso7d under the same conditions. The dissociation constants of the purified proteins for binding to double-stranded DNA (dsDNA) were determined in phosphate-buffered saline at 25 °C and were in the range from 11 μM to 22 μM with a preference for G/C rich sequences. In accordance with the extremophilic origin of their hosts, the proteins were found highly stable from pH 0 to pH 12 and at temperatures from 85.5 °C to 100 °C. Thus, these results validate eight putative "7 kDa DNA-binding" family proteins and show that they behave similarly regarding both their function and their stability among various genera and species. As Sac7d and Sso7d have found numerous uses as molecular biology reagents and artificial affinity proteins, this study also sheds light on even more attractive proteins that will facilitate engineering of novel highly robust reagents.
authors.affiliation: CRCNA, Inserm, CNRS, Université d'Angers, Université de Nantes, Nantes, France.|Université catholique de Louvain, Louvain Drug Research Institute, Advanced Drug Delivery and Biomaterials, Brussels, Belgium.
authors.forename: Valentina
authors.initials: V
authors.lastname: Kalichuk
authors.affiliation: CRCNA, Inserm, CNRS, Université d'Angers, Université de Nantes, Nantes, France.
authors.forename: Ghislaine
authors.initials: G
authors.lastname: Béhar
authors.affiliation: CRCNA, Inserm, CNRS, Université d'Angers, Université de Nantes, Nantes, France.
authors.forename: Axelle
authors.initials: A
authors.lastname: Renodon-Cornière
authors.affiliation: CRCNA, Inserm, CNRS, Université d'Angers, Université de Nantes, Nantes, France.
authors.forename: Georgi
authors.initials: G
authors.lastname: Danovski
authors.affiliation: Institut Pasteur de Montevideo, Protein Biophysics Unit, Montevideo, Uruguay.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Obal
authors.affiliation: CRCNA, Inserm, CNRS, Université d'Angers, Université de Nantes, Nantes, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Barbet
authors.affiliation: CRCNA, Inserm, CNRS, Université d'Angers, Université de Nantes, Nantes, France.
authors.forename: Barbara
authors.initials: B
authors.lastname: Mouratou
authors.affiliation: CRCNA, Inserm, CNRS, Université d'Angers, Université de Nantes, Nantes, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Pecorari
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry*; D019641:DNA, Archaeal / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D016944:Sulfolobus / Q000737:chemistry*
chemical_list: D019843:Archaeal Proteins; D019641:DNA, Archaeal; D004268:DNA-Binding Proteins; C093228:Sso7d protein, Sulfolobus; C095116:Sac7 protein, Sulfolobus