EC Number   |
General Information |
Reference |
|---|
   3.1.13.3 | evolution |
Orn is a highly conserved 3'-to-5' exonuclease |
749595 |
| 3.1.13.3 | evolution |
Orn is highly conserved among bacteria but is not likely the only nano-RNAse important for cyclic diguanylate signal transduction |
-, 752033 |
| 3.1.13.3 | malfunction |
mutation of gene orn leads to the accumulation of pGpG, which inhibits the function of glutamate-alanine-leucine (EAL) domain-containing enzymes, resulting in increased levels of cyclic-di-GMP and the consequent hyperbiofilm phenotype. EAL domain-containing enzymes hydrolyze cyclic-di-GMP to 5'-phosphoguanylyl-(3',5')-guanosine (pGpG). Mutation of orn drastically increases bacterial susceptibility to quinolones but not to tetracycline, aminoglycoside, or beta-lactam antibiotics. Upregulation of pyocin genes contributes to increased susceptibility to ciprofloxacin in the orn mutant. PrtR stability is reduced by the mutation of orn. Expression levels of prtN and PA0613 in wild-type and DELTAorn mutant strains PA14, phenotypes, overview |
749595 |
| 3.1.13.3 | malfunction |
Pseudomonas aeruginosa DELTAorn mutant has high intracellular cyclic diguanylate (c-di-GMP) levels, causing this strain to overexpress extracellular polymers and overproduce biofilm. Mutant DELTAorn cells possess highly elevated 5'-phosphoguanylyl-(3',5')-guanosine (pGpG) levels |
-, 752033 |
| 3.1.13.3 | malfunction |
the lysates from DELTAorn show 25fold decrease in 5'-phosphoguanylyl-(3',5')-guanosine (pGpG) hydrolysis. Complementation with wild-type, but not active site mutants, restores hydrolysis. Accumulation of pGpG in the DELTAorn strain inhibits PDE-As, increasing cyclic-diguanylate (c-di-GMP) concentration. Increased transcription from the cyclic-diguanylate-regulated pel promoter is observed. Additionally, the cyclic-diguanylate-governed auto-aggregation and biofilm phenotypes are elevated in the DELTAorn strain in a pel-dependent manner. Detection of elevated levels of pGpG and cyclic-diguanylate in the DELTAorn strain. Phenotype, overview |
752038 |
| 3.1.13.3 | more |
structure analysis, identification of active site structure and key residues responsible for enzymatic catalysis of CpsORN, the active site of CpsORN has a negatively charged surface, created by Asp12, Glu14, Asp112, and Asp163, overview. His66 is located near the active site and potentially stabilises the negative charge of the nucleotide. His66 residue also plays a significant role in the cleavage mechanism. His66 and His158 are completely conserved among other ORNs. Residues Ser108 and Tyr129 are not essential for the RNase activity of CpsORN |
-, 752249 |
| 3.1.13.3 | physiological function |
bacterial oligoribonuclease (Orn) is a conserved 3'-to-5' exonuclease. In Pseudomonas aeruginosa, Orn plays a major role in the hydrolysis of pGpG, which is required for cyclic-di-GMP homeostasis. Orn is involved in the degradation of nanoRNAs, which can alter global gene expression by serving as transcription initiation primers. And Orn is required for the type III secretion system and pathogenesis of Pseudomonas aeruginosa, indicating a role of Orn in the bacterial response to environmental stimuli. Orn is required for the tolerance of Pseudomonas aeruginosa to ciprofloxacin, role of Orn in bacterial resistance to antibiotics. And role of Orn in genome integrity and bacterial resistance to quinolones. Oligoribonuclease is required for bacterial resistance to fluoroquinolones |
749595 |
| 3.1.13.3 | physiological function |
cells regulate their intracellular mRNA levels by using specific ribonucleases. Oligoribonuclease (ORN) is a 3'-5' exoribonuclease for small RNA molecules, important in RNA degradation and re-utilisation |
-, 752249 |
| 3.1.13.3 | physiological function |
depletion of isoform REXO2 by RNA interference causes a strong morphological phenotype in human cells, which show a disorganized network of punctate and granular mitochondria. Lack of REXO2 protein also causes a substantial decrease of mitochondrial nucleic acid content and impaires de novo mitochondrial protein synthesis |
730733 |
| 3.1.13.3 | physiological function |
expression of isoform NrnC in Escherichia coli can complement lack of oligoribonuclease Orn. Knock down of NrnC decreases the growth ability of Bartonella henselae |
730342 |
