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Literature summary for 2.7.7.8 extracted from

  • Nurmohamed, S.; Vincent, H.A.; Titman, C.M.; Chandran, V.; Pears, M.R.; Du, D.; Griffin, J.L.; Callaghan, A.J.; Luisi, B.F.
    Polynucleotide phosphorylase activity may be modulated by metabolites in Escherichia coli (2011), J. Biol. Chem., 286, 14315-14323.
    View publication on PubMedView publication on EuropePMC
Search for more literature for 2.7.7.8

Activating Compound

Activating Compound Comment Organism Structure
citrate a PNPase-mediated response to citrate, and PNPase deletion broadly impacts on the metabolome. PNPase-dependent cells show reduced growth in the presence of increased citrate concentration. In vitro, citrate directly binds and modulates PNPase activity, and the enzyme is inhibited by binding of metal-chelated citrate, predominantly complexed as magnesium-citrate, in the active site at physiological concentrations. In the contrary, metal-free citrate is bound at a vestigial active site, where it stimulates PNPase activity, this vestigial site as an allosteric binding pocket that recognizes metal-free citrate Escherichia coli

Cloned(Commentary)

Cloned (Comment) Organism
expression of enzyme mutant R153A/R372A/R405A/R409A in Escherichia coli strain BL21(DE3) Escherichia coli

Protein Variants

Protein Variants Comment Organism
additional information construction of a strain in which PNPase activity is uncoupled from the degradosome through the deletion of the C-terminal degradosome-scaffold-ing domain of RNase E. Compared with the parental strain, significant differences are distributed across many metabolic pathways, including the Krebs cycle, amino acid synthesis, and glycolysis in the mutant strain. Salient differences are seen for amino acids and increases in the concentrations of succinate, fumarate, and malate, suggesting uncoupling of the two halves of the Krebs cycle Escherichia coli
R153A/R372A/R405A/R409A site-directed mutagenesis Escherichia coli

Inhibitors

Inhibitors Comment Organism Structure
citrate a PNPase-mediated response to citrate, and PNPase deletion broadly impacts on the metabolome. PNPase-dependent cells show reduced growth in the presence of increased citrate concentration. In vitro, citrate directly binds and modulates PNPase activity, and the enzyme is inhibited by binding of metal-chelated citrate, predominantly complexed as magnesium-citrate, in the active site at physiological concentrations. In the contrary, metal-free citrate is bound at a vestigial active site, where it stimulates PNPase activity Escherichia coli

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required Escherichia coli
Mn2+ manganese can substitute for magnesium as the catalytic metal in PNPase, and RNA degradation Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
RNAn+1 + phosphate Escherichia coli in addition to its degradative role, PNPase can also function as a polymerase, adding 3' tails to transcripts. The reverse of degradation is favored when nucleoside diphosphate rather than inorganic phosphate is present in excess RNAn + a nucleoside diphosphate
-
 r
RNAn+1 + phosphate Escherichia coli MG1655 in addition to its degradative role, PNPase can also function as a polymerase, adding 3' tails to transcripts. The reverse of degradation is favored when nucleoside diphosphate rather than inorganic phosphate is present in excess RNAn + a nucleoside diphosphate
-
 r

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-
Escherichia coli MG1655
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
RNAn+1 + phosphate in addition to its degradative role, PNPase can also function as a polymerase, adding 3' tails to transcripts. The reverse of degradation is favored when nucleoside diphosphate rather than inorganic phosphate is present in excess Escherichia coli RNAn + a nucleoside diphosphate
-
 r
RNAn+1 + phosphate substrates used for the forward degradation reaction are poly(rA) 15-mer RNA and phosphate Escherichia coli RNAn + a nucleoside diphosphate substrates used for the reverse polymerization reaction are poly(rA) 15-mer RNA and ADP r
RNAn+1 + phosphate in addition to its degradative role, PNPase can also function as a polymerase, adding 3' tails to transcripts. The reverse of degradation is favored when nucleoside diphosphate rather than inorganic phosphate is present in excess Escherichia coli MG1655 RNAn + a nucleoside diphosphate
-
 r
RNAn+1 + phosphate substrates used for the forward degradation reaction are poly(rA) 15-mer RNA and phosphate Escherichia coli MG1655 RNAn + a nucleoside diphosphate substrates used for the reverse polymerization reaction are poly(rA) 15-mer RNA and ADP r

Synonyms

Synonyms Comment Organism
PNPase
-
 Escherichia coli
polynucleotide phosphorylase
-
 Escherichia coli

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
25
-
 assay at Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.5
-
 assay at, reverse polymerization reaction Escherichia coli
8
-
 assay at, forward degradation reaction Escherichia coli

General Information

General Information Comment Organism
metabolism the Krebs cycle metabolite citrate affects the activity of Escherichia coli polynucleotide phosphorylase (PNPase) and, conversely, that cellular metabolism is affected widely by PNPase activity, a PNPase-mediated response to citrate, and PNPase deletion broadly impacts on the metabolome and on global gene expression, detailed overview Escherichia coli
physiological function metabolite-bound PNPase structure and evidence for an allosteric pocket, overview Escherichia coli