title: Crystal structure of Bacillus cereus HlyIIR, a transcriptional regulator of the gene for pore-forming toxin hemolysin II.
abstract: Production of Bacillus cereus and Bacillus anthracis toxins is controlled by a number of transcriptional regulators. Here we report the crystal structure of B. cereus HlyIIR, a regulator of the gene encoding the pore-forming toxin hemolysin II. We show that HlyIIR forms a tight dimer with a fold and overall architecture similar to the TetR family of repressors. A remarkable feature of the structure is a large internal cavity with a volume of 550 A(3) suggesting that the activity of HlyIIR is modulated by binding of a ligand, which triggers the toxin production. Virtual ligand library screening shows that this pocket can accommodate compounds with molecular masses of up to 400-500 Da. Based on structural data and previous biochemical evidence, we propose a model for HlyIIR interaction with the DNA.
authors.affiliation: Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia.
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Kovalevskiy
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Lebedev
authors.forename: Alexei K
authors.initials: AK
authors.lastname: Surin
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Solonin
authors.forename: Alfred A
authors.initials: AA
authors.lastname: Antson
mesh_terms: D000595:Amino Acid Sequence; D001409:Bacillus cereus / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D001427:Bacterial Toxins / Q000235:genetics*; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry; D019281:Dimerization; D006460:Hemolysin Proteins / Q000235:genetics*; D008024:Ligands; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D055672:Static Electricity; D040681:Structural Homology, Protein; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004268:DNA-Binding Proteins; D006460:Hemolysin Proteins; D008024:Ligands