title: Radiation-induced tetramer-to-dimer transition of Escherichia coli lactose repressor.
abstract: The wild type lactose repressor of Escherichia coli is a tetrameric protein formed by two identical dimers. They are associated via a C-terminal 4-helix bundle (called tetramerization domain) whose stability is ensured by the interaction of leucine zipper motifs. Upon in vitro gamma-irradiation the repressor losses its ability to bind the operator DNA sequence due to damage of its DNA-binding domains. Using an engineered dimeric repressor for comparison, we show here that irradiation induces also the change of repressor oligomerisation state from tetramer to dimer. The splitting of the tetramer into dimers can result from the oxidation of the leucine residues of the tetramerization domain.
authors.affiliation: Centre de Biophysique Moléculaire, CNRS, Orléans, France.
authors.forename: S
authors.initials: S
authors.lastname: Goffinont
authors.forename: M
authors.initials: M
authors.lastname: Davidkova
authors.forename: M
authors.initials: M
authors.lastname: Spotheim-Maurizot
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism* / Q000528:radiation effects*; D004247:DNA / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005720:Gamma Rays; D056968:Lac Repressors; D007930:Leucine / Q000737:chemistry; D016350:Leucine Zippers; D009875:Operator Regions, Genetic; D010084:Oxidation-Reduction; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary / Q000528:radiation effects; D012097:Repressor Proteins / Q000378:metabolism* / Q000528:radiation effects*
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D056968:Lac Repressors; C539064:LacI protein, E coli; D012097:Repressor Proteins; D004247:DNA; D007930:Leucine