1xhp
From Proteopedia
Solution Structure of the Extended U6 ISL as Observed in the U2/U6 complex from Saccharomyces cerevisiae
Overview
Intron removal in nuclear precursor mRNA is catalyzed through two transesterification reactions by a multi-megaDalton ribonucleoprotein machine called the spliceosome. A complex between U2 and U6 small nuclear RNAs is a core component of the spliceosome. Here we present an NMR structural analysis of a protein-free U2-U6 complex from Saccharomyces cerevisiae. The observed folding of the U2-U6 complex is a four-helix junction, in which the catalytically important AGC triad base-pairs only within U6 and not with U2. The base-pairing of the AGC triad extends the U6 intramolecular stem-loop (U6 ISL), and the NMR structure of this extended U6 ISL reveals structural similarities with domain 5 of group II self-splicing introns. The observed conformation of the four-helix junction could be relevant to the first, but not the second, step of splicing and may help to position the U6 ISL adjacent to the 5' splice site.
About this Structure
Full crystallographic information is available from OCA.
Reference
U2-U6 RNA folding reveals a group II intron-like domain and a four-helix junction., Sashital DG, Cornilescu G, McManus CJ, Brow DA, Butcher SE, Nat Struct Mol Biol. 2004 Dec;11(12):1237-42. Epub 2004 Nov 14. PMID:15543154 Page seeded by OCA on Sat May 3 15:02:48 2008
