Disease relevance of pps

• Strategies for increasing the availability of phosphoenolpyruvate were based on amplified expression of E. coli ppsA-encoded phosphoenolpyruvate synthase or heterologous expression of the Zymomonas mobilis glf-encoded glucose facilitator [1].
• In vitro binding of the pleiotropic transcriptional regulatory protein, FruR, to the fru, pps, ace, pts and icd operons of Escherichia coli and Salmonella typhimurium [2].
• The genes degQ, pps, and lpa-8 (sfp) are responsible for conversion of Bacillus subtilis 168 to plipastatin production [3].

High impact information on pps

• Other regulated operons were shown to bind FruR to a single site upstream of the first structural gene as follows: (1) ppsA (positive regulation); (2) icd (positive regulation); (3) aceB (positive regulation); and (4) pts (negative regulation) [2].
• Transposon mini-Tn10 insertional mutagenesis was applied to strain 406, which revealed that lpa-8 (sfp) (encoding 4'-phosphopantetheinyl transferase) and the pps operon (located between 167 and 171 degrees ) are essential for plipastatin production [3].
• We found that the growth rates of E. coli in minimal medium supplemented with succinate and with pyruvate are limited by the levels of Pck and Pps, respectively [4].
• Optimal overexpression of pck or pps increases the unrestricted growth rates on succinate and on pyruvate, respectively, to the same level attained by the wild-type growth rate on glycerol [4].
• Partial phenotypic suppression of the pfkA mutant phenotype results from Tn10 insertion very close to the pps gene, ca. 0.5 min from pgkB [5].

Chemical compound and disease context of pps

• Since Pps is needed to supply precursors for biosyntheses, we conclude that E. coli growing on pyruvate is limited by monomer supply [4].
• Modulation of phosphoenolpyruvate synthase expression increases shikimate pathway product yields in E. coli [6].

Biological context of pps

• The ppsA gene codes for PEP synthase, which converts pyruvate into phosphoenolpyruvate (PEP), an essential step in gluconeogenesis when pyruvate or lactate are used as a carbon source [7].
• Considering the characteristics of the enzyme kinetics involved, the working hypothesis was formulated that phosphoenolpyruvate synthase activity was increasingly hampered by rising oxaloacetate and 2-oxoglutarate concentrations, while at the same time pyruvate kinase activity arose due to activation by fructose 1,6-diphosphate [8].

Associations of pps with chemical compounds

• Mutants doubly deficient in phosphoenolpyruvate carboxykinase (pck) and phosphoenolpyruvate synthetase (pps) were unable to grow with succinate as the sole carbon source [9].
• A phosphoenolpyruvate-binding motif, which is observed in pyruvate phosphate dikinase, phosphoenolpyruvate: sugar phosphotransferase system enzyme I and phosphoenolpyruvate synthase, was present in the extra C-terminal sequence [10].
• An optimal expression level of phosphoenolpyruvate synthase was identified, which did not correspond to the highest expression levels of this enzyme, where the total yield of 3-dehydroshikimic acid and shikimate pathway byproducts synthesized from glucose was 51% (mol/mol) [6].
• For comparison, the theoretical maximum yield is 43% (mol/mol) for synthesis of 3-dehydroshikimic acid and shikimate pathway byproducts from glucose in lieu of amplified expression of phosphoenolpyruvate synthase [6].

Other interactions of pps

• Further increases in either Pck or Pps above the optimal levels become growth inhibitory, and the growth yield for oxygen is reduced, indicating less efficient growth [4].

References