5lqw
From Proteopedia
yeast activated spliceosome
Structural highlights
FunctionPRP8_YEAST Required for pre-spliceosome formation, which is the first step of pre-mRNA splicing. This protein is associated with snRNP U5. Has a role in branch site-3' splice site selection. Associates with the branch site-3' splice 3'-exon region. Also has a role in cell cycle.[1] [2] [3] [4] Publication Abstract from PubMedThe activated spliceosome (Bact) is in a catalytically inactive state and is remodeled into a catalytically active machine by the RNA helicase Prp2, but the mechanism is unclear. Here we describe a 3D electron cryomicroscopy structure of the S. cerevisiae Bact complex at 5.8 A resolution. Our model reveals that in Bact the catalytic U2/U6 RNA-Prp8 ribonucleoprotein core is already established, and the 5' splice site (ss) is oriented for step 1 catalysis but occluded by protein. The first step nucleophile - the branchsite adenosine - is sequestered within the Hsh155 HEAT domain and is held 50 A away from the 5'ss. Our structure suggests that Prp2 ATPase-mediated remodeling leads to conformational changes in Hsh155's HEAT domain that liberate the first step reactants for catalysis. Molecular architecture of the Saccharomyces cerevisiae activated spliceosome.,Rauhut R, Fabrizio P, Dybkov O, Hartmuth K, Pena V, Chari A, Kumar V, Lee CT, Urlaub H, Kastner B, Stark H, Luhrmann R Science. 2016 Aug 25. pii: aag1906. PMID:27562955[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also
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