Exosome complex
The exosome complex is a protein complex which can degrade RNA strands (~stop them working). In eukaryotic cells, the exosome complex is present in the cytoplasm, nucleus, and especially the nucleolus.
The core of the complex has a ring structure consisting of six proteins that all belong to the same class of RNases, the 'RNase PH-like proteins'.[1]
Exosome complexes are found in both eukaryotic cells and archaea. In bacteria a simpler complex called the degradosome carries out similar functions.
Exosome Complex Media
Top and side view of the crystal structure of the human exosome complex. See the full legend below.
Subunits and organisation of the archaeal (left) and eukaryotic (right) exosome complexes. Different proteins are numbered, showing that the archaeal exosome contains 4 different proteins, but the eukaryotic exosome contains nine different proteins. See the full legend below.
"Ribbon view" of the partial structure of the yeast exosome subunit Rrp6, Template:PDBe with α-helices in red and β-sheets in yellow.
Reaction diagrams for both hydrolytic (left) and phosphorolytic (right) 3' end degradation of RNA.
Schematic view of the archaeal (left) and eukaryotic (right) exosome complexes with the most common associated proteins. In color and marked with a star are the subunits of each complex that have catalytic activity. See below for a full legend.
Two core subunits of the archaeal exosome (Rrp41 and Rrp42), bound to a small RNA molecule (in red).
References
- ↑ Schilders G.; et al. (2006). Cell and molecular biology of the exosome: how to make or break an RNA. International Review of Cytology. Vol. 251. pp. 159–208. doi:10.1016/S0074-7696(06)51005-8. ISBN 9780123646552. PMID 16939780.