Crystal structure of an archaeal Sm protein from Sulfolobus solfataricus

Crystal Structure of Lsm3 Octamer from Saccharomyces cerevisiae: Implications for Lsm Ring Organisation and Recruitment

“…4c). However, L/Sm rings are particularly robust structures that are known to adopt larger quaternary organisations, and coaxial stacking of rings at the helix face has been seen previously in other Lsm structures (PDB codes 1H64, 1LOJ, 1M5Q, 1M8V and 1TH7 11,13,22,25 ).…”

“…[8][9][10] While Lsm proteins are found across all three domains of life, examination of the genomes of archaeal species reveals that only one to three complete Lsm genes are encoded, in contrast to the 16 or more found in eukaryotes. 7,11 Crystallographic studies have shown that these individual archaeal Lsm proteins can complex as homomeric rings of heptamers [11][12][13][14] or hexamers. 15 These X-ray crystal structures, together with density from electron microscopy of mixed eukaryotic Lsm proteins and crystal structures of dimers of the human Sm complex, have led to models of a functional assembly of seven distinct Sm/Lsm proteins in a heteromeric ring.…”

Structural features of the Bluetongue virus NS2 protein

“…archeal Sm proteins) the RNA binding region is on the surface of the ring (Kilic et al, 2005). In the rotavirus NSP2 octamer, the central hole is lined by neutral residues, and the recent cryoEM studies (Jiang et al, 2006) show that this hole is not used for RNA-binding, but rather provides a protective environment for the newly synthesized dsRNAs.…”

An Hfq-like protein in archaea: Crystal structure and functional characterization of the Sm protein from Methanococcus jannaschii

“…These motifs are separated by a region, which is not conserved in its sequence or length, the variable region (Cooper et al 1995;Hermann et al 1995;Séraphin 1995). Crystal structures of several eukaryotic and archaeal Sm/Lsm proteins have established that the conserved signature sequence defines a specific Sm-fold composed of a strongly bent five-stranded, antiparallel b-sheet capped by an N-terminal a-helix (Kambach et al 1999;Collins et al 2001;Mura et al 2001Mura et al , 2003Törö et al 2001Törö et al , 2002Thore et al 2003;Kilic et al 2005). Though bacterial Hfq proteins only exhibit faint sequence similarity to the Sm family of proteins, crystal structures of the Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa homologs (Sau-, Eco-, and Pae-Hfq) have revealed that the protein does indeed contain the distinctive Sm fold (Schumacher et al 2002;Sauter et al 2003;Nikulin et al 2005).…”