4YHW: Yeast Prp3 (296-469) In Complex With Fragment Of U4/u6 Di-snrna

Prp3 is an essential U4/U6 di-snRNP-associated protein whose functions and molecular mechanisms in pre-mRNA splicing are presently poorly understood. We show by structural and biochemical analyses that Prp3 contains a bipartite U4/U6 di-snRNA-binding region comprising an expanded ferredoxin-like fold, which recognizes a 3'-overhang of U6 snRNA, and a preceding peptide, which binds U4/U6 stem II. Phylogenetic analyses revealed that the single-stranded RNA-binding domain is exclusively found in Prp3 orthologs, thus qualifying as a spliceosome-specific RNA interaction module. The composite double-stranded/single-stranded RNA-binding region assembles cooperatively with Snu13 and Prp31 on U4/U6 di-snRNAs and inhibits Brr2-mediated U4/U6 di-snRNA unwinding in vitro. RNP-disrupting mutations in Prp3 lead to U4/U6*U5 tri-snRNP assembly and splicing defects in vivo. Our results reveal how Prp3 acts as an important bridge between U4/U6 and U5 in the tri-snRNP and comparison with a Prp24-U6 snRNA recycling complex suggests how Prp3 may be involved in U4/U6 reassembly after splicing.
PDB ID: 4YHWDownload
MMDB ID: 131134
PDB Deposition Date: 2015/2/27
Updated in MMDB: 2015/10
Experimental Method:
x-ray diffraction
Resolution: 3.25  Å
Source Organism:
Similar Structures:
Biological Unit for 4YHW: trimeric; determined by author and by software (PISA)
Molecular Components in 4YHW
Label Count Molecule
Protein (1 molecule)
U4/u6 Small Nuclear Ribonucleoprotein Prp3(Gene symbol: PRP3)
Molecule annotation
Nucleotides(2 molecules)
U4 Snrna Fragment
Molecule annotation
U6 Snrna Fragment
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB