Disease relevance of pgi

• Mutations in the genes pgi, pfkA, and ptsG resulted in a maltose Blu phenotype in Escherichia coli K-12, bringing the number of known Blu alleles to six [1].
• We now describe two new pgi mutants, one amber and the other a Mu-phage insertion, presumably both complete inactivation mutations [2].

High impact information on pgi

• A significant increase in the intracellular glucose-6-P level was observed in the presence of glucose in the pgi strain [3].
• In addition, accumulation of fructose-6-P led to the rapid degradation of ptsG mRNA in a pgi pfkA mutant strain lacking glucose-6-P [3].
• Anomalous phylogeny involving the enzyme glucose-6-phosphate isomerase [4].
• One of these mutations conferred glucose sensitivity and was localized in pgi (encoding phosphoglucose isomerase). pgi::Tn10 strains exhibit increased basal levels of expression of osmY and otsBA in exponentially growing cells and reduced osmotic inducibility of these genes [5].
• Pyruvate did not overcome the pgi effect, but glycerol 3-phosphate did, which is again consistent with the possibility that adhE expression responds to the level of reduced NAD rather than to a glycolytic intermediate [6].

Chemical compound and disease context of pgi

• The fermentation characteristics of the recombinant E. coli mutant lacking pgi were then investigated to determine the effect of overproduction of NADPH on efficient PHB production [7].
• In order to overproduce NADPH in the pentose phosphate (PP) pathway, a recombinant E. coli was constructed in which the phosphoglucose isomerase ( pgi) gene was knocked out to force the carbon flow into the PP pathway [7].
• The Escherichia coli strain Pgi-UdhA, a mutant of the strain MG1655, is deficient in both the pgi gene and the udhA gene and cannot grow on glucose as carbon and energy source [8].

Other interactions of pgi

• The unfavorable conditions generated by PHB accumulation in the pgi mutant carrying phb resulted in the highest expression of 30S ribosomal protein S1, which ultimately caused a further increase in soluble protein synthesis [7].
• However, they might be preferred for certain physiological studies, and we have prepared for this a new double mutant, strain DF214, with a Mu insertion in pgi and a deletion in zwf (flucose 6-phosphate dehydrogenase) [2].
• However, we have recently identified this ORF as the putative pgi/pmi gene coding for hypothetical bifunctional phosphoglucose/phosphomannose isomerase (PGI/PMI) [9].

References