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UniProt functional annotation for P30850 | ||
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| UniProt code: P30850. |
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| Organism: | |
Escherichia coli (strain K12). |
| Taxonomy: | |
Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales; Enterobacteriaceae; Escherichia. |
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| Function: | |
Involved in mRNA degradation. Hydrolyzes single-stranded polyribonucleotides processively in the 3' to 5' direction (PubMed:11948193). RNases 2 and R (rnr) contribute to rRNA degradation during starvation, while RNase R and PNPase (pnp) are the major contributors to quality control of rRNA during steady state growth (PubMed:21135037). This RNase is required to decrease expression of RNase PH (rnp) at 42 degrees Celsius during starvation, which in turn represses rRNA degradation (PubMed:28625967). {ECO:0000269|PubMed:11948193, ECO:0000269|PubMed:21135037, ECO:0000269|PubMed:28625967}. |
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| Catalytic activity: | |
Reaction=Exonucleolytic cleavage in the 3'- to 5'-direction to yield nucleoside 5'-phosphates.; EC=3.1.13.1; |
| Cofactor: | |
Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000269|PubMed:11948193}; |
| Activity regulation: | |
Stimulated by the presence of a monovalent cation (PubMed:11948193). Acetylation leads to decreased substrate binding and decreased catalytic activity (PubMed:26847092). {ECO:0000269|PubMed:11948193, ECO:0000269|PubMed:26847092}. |
| Biophysicochemical properties: | |
Kinetic parameters: Vmax=109800 nmol/min/mg enzyme with Poly(A) as substrate {ECO:0000269|PubMed:11948193}; Vmax=160 nmol/min/mg enzyme with 23S rRNA as substrate {ECO:0000269|PubMed:11948193}; Vmax=30 nmol/min/mg enzyme with 16S rRNA as substrate {ECO:0000269|PubMed:11948193}; Vmax=20 nmol/min/mg enzyme with 5S rRNA as substrate {ECO:0000269|PubMed:11948193}; pH dependence: Optimum pH is 7.5-9.5. {ECO:0000269|PubMed:11948193}; Temperature dependence: Optimum temperature is 50 degrees Celsius. {ECO:0000269|PubMed:11948193}; |
| Subcellular location: | |
Cytoplasm. |
| Ptm: | |
Acetylated at Lys-501 by PatZ. Deacetylated by CobB. {ECO:0000269|PubMed:26847092}. |
| Disruption phenotype: | |
In the presence of wild-type RNase PH (rph) 80- 90% reduction in viability in stationary phase (96 hours of growth) at 31 and 42 degrees Celsius or when cells are rapidly starved at 42 degrees Celsius; if rph is also absent there is no visible phenotype under these 3 growth conditions (PubMed:28625967). Its absence leads to extensive degradation of rRNA (PubMed:28625967). {ECO:0000269|PubMed:28625967}. |
| Miscellaneous: | |
In K12 strains that are derived from W1485 (including MG1655 and W3110) the rph gene has a frameshift that leads to loss of its ribonuclease PH activity. In strain K12 / MG1655(Seq)* the wild- type Rph protein has been restored (PubMed:28625967). {ECO:0000269|PubMed:28625967}. |
| Similarity: | |
Belongs to the RNR ribonuclease family. RNase II subfamily. {ECO:0000305}. |
Annotations taken from UniProtKB at the EBI.