Crystal structure of the spliceosomal 15.5kD protein bound to a U4 snRNA fragment
Classification:
RNA BINDING PROTEIN
Technique:
X-Ray Diffraction
Resolution:
2.9
R value free:
0.302
R value observed:
0.216
R value work:
0.216
Abstract of the PDB Structure's related Publication:
We have determined the crystal structure of a spliceosomal RNP complex comprising the 15.5kD protein of the human U4/U6.U5 tri-snRNP and the 5' stem-loop of U4 snRNA. The protein interacts almost exclusively with a purine-rich (5+2) internal loop within the 5' stem-loop, giving an unusual RNA fold characterized by two tandem sheared G-A base pairs, a high degree of purine stacking, and the accommodation of a single RNA base, rotated out of the RNA chain, in a pocket of the protein. Apart from yielding the structure of an important entity in the pre-mRNA splicing apparatus, this work also implies a model for the complex of the 15.5kD protein with box C/D snoRNAs. It additionally suggests a general recognition principle in a novel family of RNA binding proteins.
NHP2L1 (15.5kD) protein is a homologue of yeast Snu13 and Archaea L7Ae. Binds to a common kink-turn motif of snoRNA and U4/U6, U5 splicesomal snRNA. Belongs to C/D RNP complexes acting on pre-rRNA, pre-mRNA, snRNA and a few intron-containing tRNA.