2ba0

OverviewOverview

Exosomes emerge as central 3'-->5' RNA processing and degradation, machineries in eukaryotes and archaea. We determined crystal structures of, two 230 kDa nine subunit archaeal exosome isoforms. Both exosome isoforms, contain a hexameric ring of RNase phosphorolytic (PH) domain subunits with, a central chamber. Tungstate soaks identified three phosphorolytic active, sites in this processing chamber. A trimer of Csl4 or Rrp4 subunits forms, a multidomain macromolecular interaction surface on the RNase-PH domain, ring with central S1 domains and peripheral KH and zinc-ribbon domains., Structural and mutational analyses suggest that the S1 domains and a, subsequent neck in the RNase-PH domain ring form an RNA entry pore to the, processing chamber that only allows access of unstructured RNA. This, structural framework can mechanistically unify observed features of, exosomes, including processive degradation of unstructured RNA, the, requirement for regulatory factors to degrade structured RNA, and, left-over tails in rRNA trimming.

About this StructureAbout this Structure

2BA0 is a Protein complex structure of sequences from Archaeoglobus fulgidus. Full crystallographic information is available from OCA.

ReferenceReference

Structural framework for the mechanism of archaeal exosomes in RNA processing., Buttner K, Wenig K, Hopfner KP, Mol Cell. 2005 Nov 11;20(3):461-71. PMID:16285927

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