InterPro domain: IPR021983

This entry represents Prp8 domain IV, which adopts a RNase H like fold within its core structure but with little sequence similarity. Pre-mRNA-splicing factor 8 (Prp8), a spliceosome protein, interacts directly with the splice sites and branch regions of precursor-mRNAs and spliceosomal RNAs associated with catalysis of the two steps of splicing. Catalysis of RNA cleavage by RNase H-like proteins involves a two-metal mechanism in which adjacently-bound divalent magnesium ions promote hydrolysis by activation of a water nucleophile and stabilization of the transition-state. However, the Prp8 domain IV contains only one of the canonical metal-binding sites and the coordinating side chains are spatially conserved with respect to Mg2+-coordinating residues within the RNase H fold [ 1 ].

1. Structural elucidation of a PRP8 core domain from the heart of the spliceosome. Nat. Struct. Mol. Biol. 15, 1199-205