Structure of the yeast U2/U6 snRNA complex.
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.
Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
Jordan E
JE
Burke
Dipali G
DG
Sashital
Xiaobing
X
Zuo
Yun-Xing
YX
Wang
Samuel E
SE
Butcher
D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D012331:RNA, Fungal / Q000737:chemistry*; D012342:RNA, Small Nuclear / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D012331:RNA, Fungal; D012342:RNA, Small Nuclear; C405484:U2 small nuclear RNA; C405486:U6 small nuclear RNA