4emk | pdb_00004emk
Crystal structure of SpLsm5/6/7
Structural highlights
Function[LSM5_SCHPO] Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner. LSm5 is required for processing of pre-tRNAs, pre-rRNAs and U3 snoRNA (By similarity). [LSM7_SCHPO] Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner. Probable component of the spliceosome. [LSM6_SCHPO] Component of LSm protein complexes, which are involved in RNA processing and may function in a chaperone-like manner, facilitating the efficient association of RNA processing factors with their substrates. Component of the cytoplasmic LSM1-LSM7 complex, which is thought to be involved in mRNA degradation by activating the decapping step in the 5'-to-3' mRNA decay pathway. Component of the nuclear LSM2-LSM8 complex, which is involved in splicing of nuclear mRNAs. LSM2-LSM8 associates with multiple snRNP complexes containing the U6 snRNA (U4/U6 di-snRNP, spliceosomal U4/U6.U5 tri-snRNP, and free U6 snRNP). It binds directly to the 3'-terminal U-tract of U6 snRNA and plays a role in the biogenesis and stability of the U6 snRNP and U4/U6 snRNP complexes. LSM2-LSM8 probably also is involved degradation of nuclear pre-mRNA by targeting them for decapping, and in processing of pre-tRNAs, pre-rRNAs and U3 snoRNA (By similarity). Publication Abstract from PubMedSm-like (Lsm) proteins are ubiquitous and function in many aspects of RNA metabolism, including pre-mRNA splicing, nuclear RNA processing, mRNA decay and miRNA biogenesis. Here three crystal structures including Lsm3, Lsm4 and Lsm5/6/7 sub-complex from S. pombe are reported. These structures show that all the five individual Lsm subunits share a conserved Sm fold, and Lsm3, Lsm4, and Lsm5/6/7 form a heptamer, a trimer and a hexamer within the crystal lattice, respectively. Analytical ultracentrifugation indicates that Lsm3 and Lsm5/6/7 sub-complex exist in solution as a heptamer and a hexamer, respectively while Lsm4 undergoes a dynamic equilibrium between monomer and trimer in solution. RNA binding assays show that Lsm2/3 and Lsm5/6/7 bind to oligo(U) whereas no RNA binding is observed for Lsm3 and Lsm4. Analysis of the inter-subunit interactions in Lsm5/6/7 reveals the organization order among Lsm5, Lsm6 and Lsm7. Crystal Structures of Lsm3, Lsm4 and Lsm5/6/7 from Schizosaccharomyces pombe.,Wu D, Jiang S, Bowler MW, Song H PLoS One. 2012;7(5):e36768. Epub 2012 May 17. PMID:22615807[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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