title: The structural basis for terminator recognition by the Rho transcription termination factor.
abstract: The E. coli Rho protein disengages newly transcribed RNA from its DNA template, helping terminate certain transcripts. We have determined the X-ray crystal structure of the RNA-binding domain of Rho complexed to an RNA ligand. Filters that screen both ligand size and chemical functionality line the primary nucleic acid-binding site, imparting sequence specificity to a generic single-stranded nucleic acid-binding fold and explaining the preference of Rho for cytosine-rich RNA. The crystal packing reveals two Rho domain protomers bound to a single RNA with a single base spacer, suggesting that the strong RNA-binding sites of Rho may arise from pairing of RNA-binding modules. Dimerization of symmetric subunits on an asymmetric ligand is developed as a model for allosteric control in the action of the intact Rho hexamer.
authors.affiliation: Whitehead Institute for Biomedical Research, 9 Cambridge Center, Massachusetts 02142, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Bogden
authors.forename: D
authors.initials: D
authors.lastname: Fass
authors.forename: N
authors.initials: N
authors.lastname: Bergman
authors.forename: M D
authors.initials: MD
authors.lastname: Nichols
authors.forename: J M
authors.initials: JM
authors.lastname: Berger
mesh_terms: D000494:Allosteric Regulation / Q000235:genetics; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D012313:RNA / Q000737:chemistry*; D016601:RNA-Binding Proteins / Q000737:chemistry; D012234:Rho Factor / Q000737:chemistry*
chemical_list: D016601:RNA-Binding Proteins; D012234:Rho Factor; D012313:RNA