title: Investigating the effects of double mutation C30A/C75A on onconase structure: Studies at atomic resolution.
abstract: The structure of onconase C30A/C75A double mutant has been determined at 1.12Å resolution. The structure has high structural homology to other onconase structures. The changes being results of mutation are relatively small, distributed asymmetrically around the two mutated positions, and they are observed not only in the mutation region but expanded to entire molecule. Different conformation of Lys31 side chain that influences the hydrogen bonding network around catalytic triad is probably responsible for lower catalytic efficiency of double mutant. The decrease in thermal stability observed for the onconase variant might be explained by a less dense packing as manifested by the increase of the molecular volume and the solvent accessible surface area.
authors.affiliation: Faculty of Chemistry, Department of Crystal Physics and Crystal Chemistry, Protein Crystallography Group, Jagiellonian University, Ingardena 3, Kraków, 30060, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kurpiewska
authors.forename: Gerard
authors.initials: G
authors.lastname: Torrent
authors.forename: Marc
authors.initials: M
authors.lastname: Ribó
authors.forename: Joanna I
authors.initials: JI
authors.lastname: Loch
authors.forename: Maria
authors.initials: M
authors.lastname: Vilanova
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Lewiński
mesh_terms: D000818:Animals; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics*; D012260:Ribonucleases / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D012260:Ribonucleases; C058703:ranpirnase
keywords: atomic resolution; double mutant onconase; protein engineering; ranpirnase