A conformational switch in PRP8 mediates metal ion coordination that promotes pre-mRNA exon ligation

作者：Schellenberg Matthew J; Wu Tao; Ritchie Dustin B; Fica Sebastian; Staley Jonathan P; Atta Karim A; LaPointe Paul; MacMillan Andrew M^*

来源：Nature Structural & Molecular Biology, 2013, 20(6): 728-+.

DOI：10.1038/nsmb.2556

Splicing of pre-mRNAs in eukaryotes is catalyzed by the spliceosome, a large RNA-protein metalloenzyme. The catalytic center of the spliceosome involves a structure comprising the U2 and U6 snRNAs and includes a metal bound by U6 snRNA. The precise architecture of the splicesome active site, however, and the question of whether it includes protein components, remains unresolved. A wealth of evidence places the protein PRP8 at the heart of the spliceosome through assembly and catalysis. Here we provide evidence that the RNase H domain of PRP8 undergoes a conformational switch between the two steps of splicing, rationalizing yeast prp8 alleles that promote either the first or second step. We also show that this switch unmasks a metal-binding site involved in the second step. Together, these data establish that PRP8 is a metalloprotein that promotes exon ligation within the spliceosome.

• 出版日期2013-6