U8 snoRNA-decapping enzyme (EC 3.6.1.62) (IDP phosphatase) (IDPase) (EC 3.6.1.64) (Inosine diphosphate phosphatase) (Nucleoside diphosphate-linked moiety X motif 16) (Nudix motif 16) (Nudix hydrolase 16) (U8 snoRNA-binding protein H29K) (m7GpppN-mRNA hydrolase)
1_MAGAR 6_ RLELG 11_ EALAL 16_ GSGWR 21_ HACHA 26_ LLYAP 31_ DPGML 36_ FGRIP 41_ LRYAI 46_ LMQMR 51_ FDGRL 56_ GFPGG 61_ FVDTQ 66_ DRSLE 71_ DGLNR 76_ ELREE 81_ LGEAA 86_ AAFRV 91_ ERTDY 96_ RSSHV 101_ GSGPR 106_ VVAHF 111_ YAKRL 116_ TLEEL 121_ LAVEA 126_ GATRA 131_ KDHGL 136_ EVLGL 141_ VRVPL 146_ YTLRD 151_ GVGGL 156_ PTFLE 161_ NSFIG 166_ SAREQ 171_ LLEAL 176_ QDLGL 181_ LQSGS 186_ISGLK
1: RNA-binding and decapping enzyme that catalyzes the cleavage of the cap structure of snoRNAs and mRNAs in a metal-dependent manner. Part of the U8 snoRNP complex that is required for the accumulation of mature 5.8S and 28S rRNA. Has diphosphatase activity and removes m7G and/or m227G caps from U8 snoRNA and leaves a 5'monophosphate on the RNA. Also catalyzes the cleavage of the cap structure on mRNAs. Does not hydrolyze cap analog structures like 7-methylguanosine nucleoside triphosphate (m7GpppG). Also hydrolysis m7G- and m227G U3-capped RNAs but with less efficiencies. Has broad substrate specificity with manganese or cobalt as cofactor and can act on various RNA species. Binds to the U8 snoRNA; metal is not required for RNA-binding. May play a role in the regulation of snoRNAs and mRNAs degradation. Also acts as a phosphatase; hydrolyzes the non-canonical purine nucleotides inosine diphosphate (IDP) and deoxyinosine diphosphate (dITP) as well as guanosine diphosphate (GDP), deoxyguanosine diphosphate (dGDP), xanthine diphosphate (XDP), inosine triphosphate (ITP) and deoxyinosine triphosphate (ITP) to their respective monophosphate derivatives and does not distinguish between the deoxy- and ribose forms (PubMed:20385596, PubMed:26121039). The order of activity with different substrates is IDP > dIDP >> GDP = dGDP > XDP = ITP = dITP (PubMed:20385596). Binds strongly to GTP, ITP and XTP. Participates in the hydrolysis of dIDP/IDP and probably excludes non-canonical purines from RNA and DNA precursor pools, thus preventing their incorporation into RNA and DNA and avoiding chromosomal lesions (PubMed:20385596). Exhibits decapping activity towards NAD-capped RNAs and FAD-capped RNAs (PubMed:32432673). Exhibits decapping activity towards dpCoA-capped RNAs in vitro (By similarity)