title: Crystal structure of the 14-subunit RNA polymerase I.
abstract: Protein biosynthesis depends on the availability of ribosomes, which in turn relies on ribosomal RNA production. In eukaryotes, this process is carried out by RNA polymerase I (Pol I), a 14-subunit enzyme, the activity of which is a major determinant of cell growth. Here we present the crystal structure of Pol I from Saccharomyces cerevisiae at 3.0 Å resolution. The Pol I structure shows a compact core with a wide DNA-binding cleft and a tightly anchored stalk. An extended loop mimics the DNA backbone in the cleft and may be involved in regulating Pol I transcription. Subunit A12.2 extends from the A190 jaw to the active site and inserts a transcription elongation factor TFIIS-like zinc ribbon into the nucleotide triphosphate entry pore, providing insight into the role of A12.2 in RNA cleavage and Pol I insensitivity to α-amanitin. The A49-A34.5 heterodimer embraces subunit A135 through extended arms, thereby contacting and potentially regulating subunit A12.2.
authors.affiliation: 1] Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain [2].
authors.forename: Carlos
authors.initials: C
authors.lastname: Fernández-Tornero
authors.forename: María
authors.initials: M
authors.lastname: Moreno-Morcillo
authors.forename: Umar J
authors.initials: UJ
authors.lastname: Rashid
authors.forename: Nicholas M I
authors.initials: NM
authors.lastname: Taylor
authors.forename: Federico M
authors.initials: FM
authors.lastname: Ruiz
authors.forename: Tim
authors.initials: T
authors.lastname: Gruene
authors.forename: Pierre
authors.initials: P
authors.lastname: Legrand
authors.forename: Ulrich
authors.initials: U
authors.lastname: Steuerwald
authors.forename: Christoph W
authors.initials: CW
authors.lastname: Müller
mesh_terms: D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D010441:Peptide Chain Elongation, Translational; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D021122:Protein Subunits / Q000737:chemistry*; D012318:RNA Polymerase I / Q000737:chemistry*; D012319:RNA Polymerase II / Q000737:chemistry; D012320:RNA Polymerase III / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D014158:Transcription, Genetic
chemical_list: D021122:Protein Subunits; D004247:DNA; D012319:RNA Polymerase II; D012318:RNA Polymerase I; D012320:RNA Polymerase III