title: [Structure of Escherichia coli uracil DNA glycosylase and its complexes with nonhydrolyzable substrate analogues in solution observed by synchrotron small-angle X-ray scattering].
abstract: The structure of native and modified uracil DNA glycosylase from E. coli in solution was studied by synchrotron small-angle X-ray scattering. The modified enzyme (6His-uracyl DNA glycosylase) differs from the native one by the presence of an additional N-terminal 11-meric sequence amino acid residues including a block of six His residues. It was found that the conformations of these enzymes in solution at moderate ionic strength (60 mM NaCI) substantially differ in spite of minimal differences in the amino acid sequences and functional activity. The structure of native uracil DNA glycosylase in solution is close to that in crystal, showing a tendency for association. The interaction of this enzyme with nonhydrolyzable analogues of DNA ligands causes a partial dissociation of associates and a compactization of protein structure. At the same time, 6His-uracyl DNA glycosylase has a compact structure essentially different from the crystal one. A decrease in the ionic strength of solution results in a partial disruption of compact structure of the modified protein, without changes in its functional activity.
authors.forename: S Kh
authors.initials: SKh
authors.lastname: Timchenko
authors.forename: E A
authors.initials: EA
authors.lastname: Kubareva
authors.forename: E M
authors.initials: EM
authors.lastname: Volkov
authors.forename: O L
authors.initials: OL
authors.lastname: Voronina
authors.forename: V G
authors.initials: VG
authors.lastname: Lunin
authors.forename: D A
authors.initials: DA
authors.lastname: Gonchar
authors.forename: S Kh
authors.initials: SKh
authors.lastname: Degtiarev
authors.forename: M A
authors.initials: MA
authors.lastname: Timchenko
authors.forename: H
authors.initials: H
authors.lastname: Kihara
authors.forename: K
authors.initials: K
authors.lastname: Kimura
mesh_terms: D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D006639:Histidine / Q000737:chemistry; D006868:Hydrolysis; D009842:Oligopeptides / Q000737:chemistry; D011487:Protein Conformation; D012996:Solutions / Q000737:chemistry; D013379:Substrate Specificity; D051981:Uracil-DNA Glycosidase / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D029968:Escherichia coli Proteins; C471213:His-His-His-His-His-His; D009842:Oligopeptides; D012996:Solutions; D006639:Histidine; D051981:Uracil-DNA Glycosidase