InterPro domain: IPR027408

Polynucleotide phosphorylase (PNPase) is a polyribonucleotide nucleotidyl transferase 2.7.7.8 that degrades mRNA in prokaryotes. Polynucleotide phosphorylase and the Ribonuclease PH (RNase PH) family possess a common domain represented by this entry. This suggests similar structures and mechanisms of action for these 3'-->5' phosphorolytic enzymes [ 1 ]. In the case of PNPase, the core domain is found duplicated [ 2 ].

1. Comparative sequence analysis of ribonucleases HII, III, II PH and D. Nucleic Acids Res. 25, 3187-95
2. A duplicated fold is the structural basis for polynucleotide phosphorylase catalytic activity, processivity, and regulation. Structure 8, 1215-26