InterPro domain: IPR009097

This entry represents a beta-barrel domain consisting of a duplication of a beta/alpha/beta/alpha/beta motif, which is found in plant cyclic phosphodiesterases (CPDases) [ 1 ], as well as catalytic domains from mammalian 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) [ 2 ], and bacterial and archaeal LigT-like 2',3'-cyclic phosphodiesterases (originally identified as 2'-5' RNA ligases) [ 3 ]. This beta-barrel domain is similar in structure to the beta-barrel found in prokaryotic DNA topoisomerases I and III.

The catalytic domain of CNPase from animals catalyzes the hydrolysis of nucleoside 2',3'-cyclic monophosphates to nucleoside 2'-monophosphates [ 4 ]. The archaeobacterial LigT-like enzymes hydrolyze 2',3'-cyclic phosphate in (oligo)nucleotides and join the produced 2'-phosphate to a 5'-hydroxyl group of another (oligo)nucleotide to form atypical 2',5'-linkages. Such activity has not been reported for CNPase [ 5 ].

1. Crystal structures of the semireduced and inhibitor-bound forms of cyclic nucleotide phosphodiesterase from Arabidopsis thaliana. J. Biol. Chem. 277, 1419-25
2. Solution structure of the catalytic domain of RICH protein from goldfish. FEBS J. 274, 1600-9
3. Structure and mechanism of E. coli RNA 2',3'-cyclic phosphodiesterase. RNA 20, 1697-705
4. Determinants of ligand binding and catalytic activity in the myelin enzyme 2',3'-cyclic nucleotide 3'-phosphodiesterase. Sci Rep 5, 16520
5. Crystallographic analysis of the reaction cycle of 2',3'-cyclic nucleotide 3'-phosphodiesterase, a unique member of the 2H phosphoesterase family. J. Mol. Biol. 425, 4307-22