5c0y
From Proteopedia
Crystal structure of the Rrp6 catalytic domain bound to poly(U) RNA
Structural highlights
Function[RRP6_YEAST] Nuclear-specific catalytic component of the RNA exosome complex which has 3'->5' exoribonuclease activity and participates in a multitude of cellular RNA processing and degradation events. In the nucleus, the RNA exosome complex is involved in proper maturation of stable RNA species such as rRNA, snRNA and snoRNA, in the elimination of RNA processing by-products and non-coding 'pervasive' transcripts, such as antisense RNA species and cryptic unstable transcripts (CUTs), and of mRNAs with processing defects, thereby limiting or excluding their export to the cytoplasm. The catalytic inactive RNA exosome core complex of 9 subunits (Exo-9) is proposed to play a pivotal role in the binding and presentation of RNA for ribonucleolysis, and to serve as a scaffold for the association with catalytic subunits and accessory proteins or complexes. RRP6 has 3'-5' exonuclease activity which is not modulated upon association with Exo-9 suggesting that the complex inner RNA-binding path is not used to access its active site.[1] [2] [3] [4] Publication Abstract from PubMedThe eukaryotic exosome is a conserved RNA-degrading complex that functions in RNA surveillance, turnover and processing. How the same machinery can either completely degrade or precisely trim RNA substrates has long remained unexplained. Here we report the crystal structures of a yeast nuclear exosome containing the 9-subunit core, the 3'-5' RNases Rrp44 and Rrp6, and the obligate Rrp6-binding partner Rrp47 in complex with different RNAs. The combined structural and biochemical data of this 12-subunit complex reveal how a single-stranded RNA can reach the Rrp44 or Rrp6 active sites directly or can bind Rrp6 and be threaded via the central channel towards the distal RNase Rrp44. When a bulky RNA is stalled at the entrance of the channel, Rrp6-Rrp47 swings open. The results suggest how the same molecular machine can coordinate processive degradation and partial trimming in an RNA-dependent manner by a concerted swinging mechanism of the two RNase subunits. RNA degradation paths in a 12-subunit nuclear exosome complex.,Makino DL, Schuch B, Stegmann E, Baumgartner M, Basquin C, Conti E Nature. 2015 Jul 29. doi: 10.1038/nature14865. PMID:26222026[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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