EC Number   |
General Information |
Reference |
|---|
   2.7.7.8 | evolution |
human polynucleotide phosphorylase is an evolutionary conserved RNA-processing enzyme. PNPase contains five motifs that are conspicuously preserved through evolution extending from prokaryotes and plants to mammals. Although hPNPase structurally and biochemically resembles PNPase of other species, overexpression and inhibition studies reveal that hPNPase has evolved to serve more specialized and diversified functions in humans |
723310 |
| 2.7.7.8 | evolution |
polynucleotide phosphorylase is a conserved, widely distributed phosphorolytic 3'-5' exoribonuclease |
722555 |
| 2.7.7.8 | evolution |
two domains, both resembling closely the phosphorolytic exoribonuclease RNase PH, EC 27.7.56, almost certainly have originated from duplication and fusion of an ancestral gene. While the C-terminal RNase PH-like domain catalyses phosphorolytic attack of RNA, the N-terminal domain has lost this capacity. Instead, it contributes to the ring-like quaternary structure of the trimeric PNPase assembly |
-, 723315 |
| 2.7.7.8 | malfunction |
deletion of the pnp gene, encoding polynucleotide phosphorylase, results in increased biofilm formation in Escherichia coli |
-, 721941 |
| 2.7.7.8 | malfunction |
enzyme depletion decreases splicing efficiency and inhibits intron degradation, effects on intron metabolism, overview. In mutants lacking cpPNPase activity, unusual RNA patterns occur, intron-containing fragments also accumulate in mutants. Mutants show gene-dependent and intermediate RNA phenotypes, suggesting that reduced enzyme activity differentially affects chloroplast transcripts |
-, 723424 |
| 2.7.7.8 | malfunction |
in a liver mitochondria from a liver-specific PNPase knockout mouse model, the decrease in functional electron transport chain complexes is responsible for decreased respiration. Liver mitochondria from liver-specific knockout mice display disordered circular and smooth inner membrane criste, similar to mitochondria having impaired components of oxidative phosphorylation pathways. Citrate synthase activity, routinely used as a marker of aerobic capacity, also decreases in the liver of PNPase knockout mice compared with the wild-type mice |
723310 |
| 2.7.7.8 | malfunction |
inhibition of the enzyme by shRNA or stable overexpression of miR-221 protects melanoma cells from IFN-beta-mediated growth inhibition |
723628 |
| 2.7.7.8 | malfunction |
loss-of-function mutations in pnp result in a decreased stability of several sRNAs including RyhB, SgrS, and CyaR and also decrease both the negative and positive regulation by sRNAs. The defect in stability of CyaR and in negative and positive regulation are suppressed by deletion mutations in RNase E. Lack of sRNA-mediated regulation in the absence of an active form of PNPase is due to the rapid turnover of sRNA resulting from an increase in RNase E activity and/or an increase in access of other ribonucleases to sRNAs. The defect in sRNA regulation caused by the pnp mutations is independent of Hfq. While Hfq does not appear to be limiting, it seems possible that lack of PNPase leads to inactivation of Hfq |
-, 723757 |
| 2.7.7.8 | malfunction |
PNPase-deficient mutant is hypersensitive to oxidative challenges |
-, 707489 |
| 2.7.7.8 | malfunction |
spontaneous mutations resulting from replication errors, which are normally repaired by the mismatch repair system, are sharply reduced in a polynucleotide phosphorylase-deficient Escherichia coli strain |
722550 |
