title: Molecular motion of spin labeled side chains in the C-terminal domain of RGL2 protein: a SDSL-EPR and MD study.
abstract: Five singly spin labeled side chains at surface sites in the C-terminal domain of RGL2 protein have been analyzed to investigate the general relationship between nitroxide side chain mobility and protein structure. At these sites, the structural perturbation produced by replacement of a native residue with a nitroxide side chain appears to be very slight at the level of the backbone fold. The primary determinants of the nitroxide side chain mobility are backbone dynamics and tertiary interactions. On the exposed surfaces of alpha-helices, the side chain mobility is not restricted by tertiary interactions but appears to be determined by backbone dynamics, while in loop sites, the side chain mobility is even higher. For a better understanding of the changes in the EPR spectral line shape, molecular dynamics simulations were performed and found in agreement with EPR spectral data.
authors.affiliation: Department of Chemistry, University of Siena, Via A. Moro, 53100 Siena, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Pistolesi
authors.forename: Elisa
authors.initials: E
authors.lastname: Ferro
authors.forename: Annalisa
authors.initials: A
authors.lastname: Santucci
authors.forename: Riccardo
authors.initials: R
authors.lastname: Basosi
authors.forename: Lorenza
authors.initials: L
authors.lastname: Trabalzini
authors.forename: Rebecca
authors.initials: R
authors.lastname: Pogni
mesh_terms: D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D020662:Guanine Nucleotide Exchange Factors; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010957:Plasmids; D011487:Protein Conformation; D013113:Spin Labels; D020691:rab GTP-Binding Proteins / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D020662:Guanine Nucleotide Exchange Factors; C102739:RGL2 protein, human; D013113:Spin Labels; D020691:rab GTP-Binding Proteins