title: Rearrangement of the RNA polymerase subunit H and the lower jaw in archaeal elongation complexes.
abstract: The lower jaws of archaeal RNA polymerase and eukaryotic RNA polymerase II include orthologous subunits H and Rpb5, respectively. The tertiary structure of H is very similar to the structure of the C-terminal domain of Rpb5, and both subunits are proximal to downstream DNA in pre-initiation complexes. Analyses of reconstituted euryarchaeal polymerase lacking subunit H revealed that H is important for open complex formation and initial transcription. Eukaryotic Rpb5 rescues activity of the DeltaH enzyme indicating a strong conservation of function for this subunit from archaea to eukaryotes. Photochemical cross-linking in elongation complexes revealed a striking structural rearrangement of RNA polymerase, bringing subunit H near the transcribed DNA strand one helical turn downstream of the active center, in contrast to the positioning observed in preinitiation complexes. The rearrangement of subunits H and A'' suggest a major conformational change in the archaeal RNAP lower jaw upon formation of the elongation complex.
authors.affiliation: Lehrstuhl für Mikrobiologie, Universität Regensburg, 93053 Regensburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Grünberg
authors.forename: Christoph
authors.initials: C
authors.lastname: Reich
authors.forename: Mirijam E
authors.initials: ME
authors.lastname: Zeller
authors.forename: Michael S
authors.initials: MS
authors.lastname: Bartlett
authors.forename: Michael
authors.initials: M
authors.lastname: Thomm
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism; D001483:Base Sequence; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D021122:Protein Subunits / Q000737:chemistry* / Q000378:metabolism; D012319:RNA Polymerase II / Q000737:chemistry / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D019843:Archaeal Proteins; D021122:Protein Subunits; D004247:DNA; D012319:RNA Polymerase II; D012321:DNA-Directed RNA Polymerases