title: RNA polymerase and transcription elongation factor Spt4/5 complex structure.
abstract: Spt4/5 in archaea and eukaryote and its bacterial homolog NusG is the only elongation factor conserved in all three domains of life and plays many key roles in cotranscriptional regulation and in recruiting other factors to the elongating RNA polymerase. Here, we present the crystal structure of Spt4/5 as well as the structure of RNA polymerase-Spt4/5 complex using cryoelectron microscopy reconstruction and single particle analysis. The Spt4/5 binds in the middle of RNA polymerase claw and encloses the DNA, reminiscent of the DNA polymerase clamp and ring helicases. The transcription elongation complex model reveals that the Spt4/5 is an upstream DNA holder and contacts the nontemplate DNA in the transcription bubble. These structures reveal that the cellular RNA polymerases also use a strategy of encircling DNA to enhance its processivity as commonly observed for many nucleic acid processing enzymes including DNA polymerases and helicases.
authors.affiliation: Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Brianna J
authors.initials: BJ
authors.lastname: Klein
authors.forename: Daniel
authors.initials: D
authors.lastname: Bose
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Baker
authors.forename: Zahirah M
authors.initials: ZM
authors.lastname: Yusoff
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhang
authors.forename: Katsuhiko S
authors.initials: KS
authors.lastname: Murakami
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000502:physiology*; D020285:Cryoelectron Microscopy / Q000379:methods; D018360:Crystallography, X-Ray / Q000379:methods; D004247:DNA / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000502:physiology*; D009696:Nucleic Acids / Q000737:chemistry; D020027:Pyrococcus furiosus / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors / Q000502:physiology*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D009687:Nuclear Proteins; D009696:Nucleic Acids; C080991:SPT4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035602:Transcriptional Elongation Factors; C069940:SPT5 transcriptional elongation factor; D004247:DNA; D012321:DNA-Directed RNA Polymerases; D004259:DNA-Directed DNA Polymerase