title: Direct atomic force microscopy visualization of integration host factor-induced DNA bending structure of the promoter regulatory region on the Pseudomonas TOL plasmid.
abstract: Atomic force microscopy (AFM) was used to analyze DNA bending induced by integration host factor (IHF). The direct AFM visualization of IHF-DNA complexes on the OP1 promoter regulatory regions on the Pseudomonas TOL plasmid showed that there was no intrinsic DNA bend in the OP1 promoter region, but a sharp DNA bend was induced by binding of IHF to the region between the upstream regulatory sequence and the promoter sequence. The DNA bending angles were distributed with a mean bend angle of 123 degrees. The IHF-DNA complexes were shown to bend at the IHF binding site giving rise to an asymmetric structure. These results provide direct evidence that IHF is required functionally for activation of OP1 transcription and support the DNA-loop model that the sharp DNA bend induced by binding of IHF facilitates the contact between RNA polymerase bound by the promoter sequence and XylR protein attached to the upstream sequence in the OP1 promoter.
authors.affiliation: Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Gi Hun
authors.initials: GH
authors.lastname: Seong
authors.forename: Eiry
authors.initials: E
authors.lastname: Kobatake
authors.forename: Koshiro
authors.initials: K
authors.lastname: Miura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakazawa
authors.forename: Masuo
authors.initials: M
authors.lastname: Aizawa
mesh_terms: D001426:Bacterial Proteins / Q000494:pharmacology* / Q000648:ultrastructure*; D001665:Binding Sites; D004269:DNA, Bacterial / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure*; D004268:DNA-Binding Proteins / Q000494:pharmacology / Q000648:ultrastructure; D034982:Integration Host Factors; D046911:Macromolecular Substances; D018625:Microscopy, Atomic Force / Q000379:methods*; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000187:drug effects / Q000648:ultrastructure; D011401:Promoter Regions, Genetic; D011549:Pseudomonas / Q000235:genetics* / Q000648:ultrastructure; D012045:Regulatory Sequences, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D034982:Integration Host Factors; D046911:Macromolecular Substances; C440503:integration host factor, Pseudomonas