4f7u | pdb_00004f7u

The 6S snRNP assembly intermediate

spinqualitylabelsall models 4f7u, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4f7u is a 12 chain structure with sequence from Drosophila melanogaster, Mus musculus and Xenopus laevis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: P6G Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SMD1_MOUSE Core component of the spliceosomal U1, U2, U4 and U5 small nuclear ribonucleoproteins (snRNPs), the building blocks of the spliceosome. Thereby, plays an important role in the splicing of cellular pre-mRNAs. Most spliceosomal snRNPs contain a common set of Sm proteins SNRPB, SNRPD1, SNRPD2, SNRPD3, SNRPE, SNRPF and SNRPG that assemble in an heptameric protein ring on the Sm site of the small nuclear RNA to form the core snRNP. May act as a charged protein scaffold to promote snRNP assembly or strengthen snRNP-snRNP interactions through nonspecific electrostatic contacts with RNA (By similarity). Publication Abstract from PubMed Small nuclear ribonucleoproteins (snRNPs) represent key constituents of major and minor spliceosomes. snRNPs contain a common core, composed of seven Sm proteins bound to snRNA, which forms in a step-wise and factor-mediated reaction. The assembly chaperone pICln initially mediates the formation of an otherwise unstable pentameric Sm protein unit. This so-called 6S complex docks subsequently onto the SMN complex, which removes pICln and enables the transfer of pre-assembled Sm proteins onto snRNA. X-ray crystallography and electron microscopy was used to investigate the structural basis of snRNP assembly. The 6S complex structure identifies pICln as an Sm protein mimic, which enables the topological organization of the Sm pentamer in a closed ring. A second structure of 6S bound to the SMN complex components SMN and Gemin2 uncovers a plausible mechanism of pICln elimination and Sm protein activation for snRNA binding. Our studies reveal how assembly factors facilitate formation of RNA-protein complexes in vivo. Structural Basis of Assembly Chaperone- Mediated snRNP Formation.,Grimm C, Chari A, Pelz JP, Kuper J, Kisker C, Diederichs K, Stark H, Schindelin H, Fischer U Mol Cell. 2013 Jan 15. pii: S1097-2765(12)01018-0. doi:, 10.1016/j.molcel.2012.12.009. PMID:23333303 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Nucleoprotein 3D structures

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