1m8v
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Structure of Pyrococcus abyssii Sm Protein in Complex with a Uridine Heptamer
OverviewOverview
The Sm proteins are conserved in all three domains of life and are always, associated with U-rich RNA sequences. Their proposed function is to, mediate RNA-RNA interactions. We present here the crystal structures of, Pyrococcus abyssi Sm protein (PA-Sm1) and its complex with a uridine, heptamer. The overall structure of the protein complex, a heptameric ring, with a central cavity, is similar to that proposed for the eukaryotic Sm, core complex and found for other archaeal Sm proteins. RNA molecules bind, to the protein at two different sites. They interact specifically inside, the ring with three highly conserved residues, defining the, uridine-binding pocket. In addition, nucleotides also interact on the, surface formed by the N-terminal alpha-helix as well as a conserved, aromatic residue in beta-strand 2 of the PA-Sm1 protein. The mutation of, this conserved aromatic residue shows the importance of this second site, for the discrimination between RNA sequences. Given the high structural, homology between archaeal and eukaryotic Sm proteins, the PA-Sm1.RNA, complex provides a model for how the small nuclear RNA contacts the Sm, proteins in the Sm core. In addition, it suggests how Sm proteins might, exert their function as modulators of RNA-RNA interactions.
About this StructureAbout this Structure
1M8V is a Single protein structure of sequence from Pyrococcus abyssi with CA and U as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures of the Pyrococcus abyssi Sm core and its complex with RNA. Common features of RNA binding in archaea and eukarya., Thore S, Mayer C, Sauter C, Weeks S, Suck D, J Biol Chem. 2003 Jan 10;278(2):1239-47. Epub 2002 Oct 29. PMID:12409299
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