Structure of the yeast U2/U6 snRNA complex
- 1Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
- 2Advanced Photon Source, Argonne National Laboratory, Chicago, Illinois 60437, USA
- 3National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
Abstract
The U2/U6 snRNA complex is a conserved and essential component of the active spliceosome that interacts with the pre-mRNA substrate and essential protein splicing factors to promote splicing catalysis. Here we have elucidated the solution structure of a 111-nucleotide U2/U6 complex using an approach that integrates SAXS, NMR, and molecular modeling. The U2/U6 structure contains a three-helix junction that forms an extended “Y” shape. The U6 internal stem–loop (ISL) forms a continuous stack with U2/U6 Helices Ib, Ia, and III. The coaxial stacking of Helix Ib on the U6 ISL is a configuration that is similar to the Domain V structure in group II introns. Interestingly, essential features of the complex—including the U80 metal binding site, AGC triad, and pre-mRNA recognition sites—localize to one face of the molecule. This observation suggests that the U2/U6 structure is well-suited for orienting substrate and cofactors during splicing catalysis.
Keywords
Footnotes
-
↵5 Corresponding author.
E-mail butcher{at}biochem.wisc.edu.
-
Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.031138.111.
- Received October 26, 2011.
- Accepted December 16, 2011.
- Copyright © 2012 RNA Society