title: Structure of the Escherichia coli FlhDC complex, a prokaryotic heteromeric regulator of transcription.
abstract: The hetero-oligomeric complex of the FlhD and FlhC proteins (FlhDC) regulates transcription from several flagellar and non-flagellar operons in bacteria. The crystallographic structure of the Escherichia coli FlhDC complex has been solved to 3.0 A resolution, revealing a hexameric FlhD4FlhC2 assembly. In the complex, each FlhC protomer binds an FlhD2 dimer; the conformation of the dimer in the complex differs significantly from its conformation in the absence of FlhC. FlhC has a novel tertiary fold that includes a heretofore unrecognized zinc-binding site in which the ion is ligated by four cysteine residues. Gel shift experiments show that binding of the FlhDC complex to a cognate promoter bends the DNA by approximately 111 degrees . The structure of the FlhDC complex is compatible with models in which a fragment of operator DNA, at least 48 base-pairs in length, wraps around the complex and bends significantly when binding.
authors.affiliation: Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: Shuying
authors.initials: S
authors.lastname: Wang
authors.forename: Rhonda T
authors.initials: RT
authors.lastname: Fleming
authors.forename: Edwin M
authors.initials: EM
authors.lastname: Westbrook
authors.forename: Philip
authors.initials: P
authors.lastname: Matsumura
authors.forename: David B
authors.initials: DB
authors.lastname: McKay
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D050436:Regulatory Elements, Transcriptional / Q000235:genetics; D015534:Trans-Activators / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015032:Zinc / Q000737:chemistry
chemical_list: D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D015534:Trans-Activators; C090552:flhC protein, E coli; C090553:flhD protein, E coli; D004247:DNA; D015032:Zinc