title: NMR studies on the surface accessibility of the archaeal protein Sso7d by using TEMPOL and Gd(III)(DTPA-BMA) as paramagnetic probes.
abstract: Understanding how proteins are approached by surrounding molecules is fundamental to increase our knowledge of life at atomic resolution. Here, the surface accessibility of a multifunctional small protein, the archaeal protein Sso7d from Sulfolobus solfataricus, has been investigated by using TEMPOL and Gd(III)(DTPA-BMA) as paramagnetic probes. The DNA binding domain of Sso7d appears very accessible both to TEMPOL and Gd(III)(DTPA-BMA). Differences in paramagnetic attenuation profiles of (1)H-(15)N HSQC protein backbone amide correlations, observed in the presence of the latter paramagnetic probes, are consistent with the hydrogen bond acceptor capability of the N-oxyl moiety of TEMPOL to surface exposed Sso7d amide groups. By using the gadolinium complex as a paramagnetic probe a better agreement between Sso7d structural features and attenuation profile is achieved. It is interesting to note that the protein P-loop region, in spite of the high surface exposure predicted by the available protein structures, is not approached by TEMPOL and only partially by Gd(III)(DTPA-BMA).
authors.affiliation: Università degli Studi di Siena, Dipartimento di Biologia Molecolare, via A. Fiorentina 1, 53100 Siena, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bernini
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Venditti
authors.forename: Ottavia
authors.initials: O
authors.lastname: Spiga
authors.forename: Arianna
authors.initials: A
authors.lastname: Ciutti
authors.forename: Filippo
authors.initials: F
authors.lastname: Prischi
authors.forename: Roberto
authors.initials: R
authors.lastname: Consonni
authors.forename: Lucia
authors.initials: L
authors.lastname: Zetta
authors.forename: Ivana
authors.initials: I
authors.lastname: Arosio
authors.forename: Paola
authors.initials: P
authors.lastname: Fusi
authors.forename: Annamaria
authors.initials: A
authors.lastname: Guagliardi
authors.forename: Neri
authors.initials: N
authors.lastname: Niccolai
mesh_terms: D000577:Amides / Q000737:chemistry; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D019786:Gadolinium DTPA / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009587:Nitrogen Isotopes / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011522:Protons; D013113:Spin Labels; D013499:Surface Properties
chemical_list: D000577:Amides; D019843:Archaeal Proteins; D003497:Cyclic N-Oxides; D004268:DNA-Binding Proteins; D009587:Nitrogen Isotopes; D011522:Protons; D013113:Spin Labels; C093228:Sso7d protein, Sulfolobus; C064925:gadodiamide; D019786:Gadolinium DTPA; C001803:tempol