1lpw
Solution structure of the yeast spliceosomal U2 snRNA-intron branch site helix featuring a conserved pseudouridine
OverviewOverview
Pairing of a consensus sequence of the precursor (pre)-mRNA intron with a short region of the U2 small nuclear (sn)RNA during assembly of the eukaryotic spliceosome results in formation of a complementary helix of seven base pairs with a single unpaired adenosine residue. The 2' OH of this adenosine, called the branch site, brings about nucleophilic attack at the pre-mRNA 5' splice site in the first step of splicing. Another feature of this pairing is the phylogenetic conservation of a pseudouridine (psi) residue in U2 snRNA nearly opposite the branch site. We show that the presence of this psi in the pre-mRNA branch-site helix of Saccharomyces cerevisiae induces a dramatically altered architectural landscape compared with that of its unmodified counterpart. The psi-induced structure places the nucleophile in an accessible position for the first step of splicing.
About this StructureAbout this Structure
Full crystallographic information is available from OCA.
ReferenceReference
Sculpting of the spliceosomal branch site recognition motif by a conserved pseudouridine., Newby MI, Greenbaum NL, Nat Struct Biol. 2002 Dec;9(12):958-65. PMID:12426583 Page seeded by OCA on Sat May 3 00:09:43 2008