8q7n

cryo-EM structure of the human spliceosomal B complex protomer (tri-snRNP core region)

spinqualitylabelsall models 8q7n, resolution 3.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8q7n is a 10 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.1Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SF3A1_HUMAN Subunit of the splicing factor SF3A required for 'A' complex assembly formed by the stable binding of U2 snRNP to the branchpoint sequence (BPS) in pre-mRNA. Sequence independent binding of SF3A/SF3B complex upstream of the branch site is essential, it may anchor U2 snRNP to the pre-mRNA. May also be involved in the assembly of the 'E' complex. Publication Abstract from PubMed The B complex is a key intermediate stage of spliceosome assembly. To improve the structural resolution of monomeric, human spliceosomal B (hB) complexes and thereby generate a more comprehensive hB molecular model, we determined the cryo-EM structure of B complex dimers formed in the presence of ATP gamma S. The enhanced resolution of these complexes allows a finer molecular dissection of how the 5' splice site (5'ss) is recognized in hB, and new insights into molecular interactions of FBP21, SNU23 and PRP38 with the U6/5'ss helix and with each other. It also reveals that SMU1 and RED are present as a heterotetrameric complex and are located at the interface of the B dimer protomers. We further show that MFAP1 and UBL5 form a 5' exon binding channel in hB, and elucidate the molecular contacts stabilizing the 5' exon at this stage. Our studies thus yield more accurate models of protein and RNA components of hB complexes. They further allow the localization of additional proteins and protein domains (such as SF3B6, BUD31 and TCERG1) whose position was not previously known, thereby uncovering new functions for B-specific and other hB proteins during pre-mRNA splicing. Cryo-EM analyses of dimerized spliceosomes provide new insights into the functions of B complex proteins.,Zhang Z, Kumar V, Dybkov O, Will CL, Urlaub H, Stark H, Luhrmann R EMBO J. 2024 Mar;43(6):1065-1088. doi: 10.1038/s44318-024-00052-1. Epub 2024 Feb , 21. PMID:38383864 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also U5-15kD

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