title: Molecular Structures of Transcribing RNA Polymerase I.
abstract: RNA polymerase I (Pol I) is a 14-subunit enzyme that solely synthesizes pre-ribosomal RNA. Recently, the crystal structure of apo Pol I gave unprecedented insight into its molecular architecture. Here, we present three cryo-EM structures of elongating Pol I, two at 4.0 Å and one at 4.6 Å resolution, and a Pol I open complex at 3.8 Å resolution. Two modules in Pol I mediate the narrowing of the DNA-binding cleft by closing the clamp domain. The DNA is bound by the clamp head and by the protrusion domain, allowing visualization of the upstream and downstream DNA duplexes in one of the elongation complexes. During formation of the Pol I elongation complex, the bridge helix progressively folds, while the A12.2 C-terminal domain is displaced from the active site. Our results reveal the conformational changes associated with elongation complex formation and provide additional insight into the Pol I transcription cycle.
authors.affiliation: European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
authors.forename: Lucas
authors.initials: L
authors.lastname: Tafur
authors.affiliation: European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
authors.forename: Yashar
authors.initials: Y
authors.lastname: Sadian
authors.affiliation: European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
authors.forename: Niklas A
authors.initials: NA
authors.lastname: Hoffmann
authors.affiliation: European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany; European Molecular Biology Laboratory (EMBL), Hamburg Unit, Notkestrasse 85, 22607 Hamburg, Germany.
authors.forename: Arjen J
authors.initials: AJ
authors.lastname: Jakobi
authors.affiliation: European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
authors.forename: Rene
authors.initials: R
authors.lastname: Wetzel
authors.affiliation: European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
authors.forename: Wim J H
authors.initials: WJH
authors.lastname: Hagen
authors.affiliation: European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Sachse
authors.affiliation: European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany. Electronic address: cmueller@embl.de.
authors.forename: Christoph W
authors.initials: CW
authors.lastname: Müller
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D008958:Models, Molecular; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D017510:Protein Folding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012313:RNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012318:RNA Polymerase I / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D021122:Protein Subunits; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D012313:RNA; D004247:DNA; D012318:RNA Polymerase I
keywords: Pol I; RNA polymerase I; cryoelectron microscopy; elongation complex; rDNA transcription; transcription