Purification and characterization of glpX-encoded fructose 1, 6-bisphosphatase, a new enzyme of the glycerol 3-phosphate regulon of Escherichia coli.

Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.
Journal of Bacteriology (Impact Factor: 2.69). 11/2000; 182(19):5624-7.
Source: PubMed

ABSTRACT In Escherichia coli, gene products of the glp regulon mediate utilization of glycerol and sn-glycerol 3-phosphate. The glpFKX operon encodes glycerol diffusion facilitator, glycerol kinase, and as shown here, a fructose 1,6-bisphosphatase that is distinct from the previously described fbp-encoded enzyme. The purified enzyme was dimeric, dependent on Mn(2+) for activity, and exhibited an apparent K(m) of 35 microM for fructose 1,6-bisphosphate. The enzyme was inhibited by ADP and phosphate and activated by phosphoenolpyruvate.

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Available from: Janet L. Donahue, Aug 31, 2015
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    • "Prokaryotic Class I and Class II FBPase are distantly related to each other [13]. Class I contains typical FBPase domain [14], while Class II contains FBPase_glpX domain [15]. When we searched against Pfam database to identify the two kinds of domains in all the available eubacterial F/SBPase whose dual function has been experimentally determined, eight sequences, six of which are from proteobacteria and two from cyanobacteria, were obtained. "
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    BMC Evolutionary Biology 10/2012; 12(1):208. DOI:10.1186/1471-2148-12-208 · 3.41 Impact Factor
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    • "As is the case in Phaeodactylum, one of the T. oceanica FBAs from each compartment (FBA1, FBA2, FBA6) appears to act through metal catalysis (class II) while the second (FBA3, FBA5, FBA4) is predicted to use Schiff-base catalysis (class I) instead. While the metal cofactor of different class II FBAs was found to be Mn2+ [28], Zn2+ [29] or Cd2+ [30] in Escherichia coli, the orthologous FBAs of T. oceanica apparently are differentially regulated through the availability of iron, suggesting the involved metal in these enzymes might be Fe2+, and implying a pairwise substitution by class I enzymes. "
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    ABSTRACT: Background Biogeochemical elemental cycling is driven by primary production of biomass via phototrophic phytoplankton growth, with 40% of marine productivity being assigned to diatoms. Phytoplankton growth is widely limited by the availability of iron, an essential component of the photosynthetic apparatus. The oceanic diatom Thalassiosira oceanica shows a remarkable tolerance to low-iron conditions and was chosen as a model for deciphering the cellular response upon shortage of this essential micronutrient. Results The combined efforts in genomics, transcriptomics and proteomics reveal an unexpected metabolic flexibility in response to iron availability for T. oceanica CCMP1005. The complex response comprises cellular retrenchment as well as remodeling of bioenergetic pathways, where the abundance of iron-rich photosynthetic proteins is lowered, whereas iron-rich mitochondrial proteins are preserved. As a consequence of iron deprivation, the photosynthetic machinery undergoes a remodeling to adjust the light energy utilization with the overall decrease in photosynthetic electron transfer complexes. Conclusions Beneficial adaptations to low-iron environments include strategies to lower the cellular iron requirements and to enhance iron uptake. A novel contribution enhancing iron economy of phototrophic growth is observed with the iron-regulated substitution of three metal-containing fructose-bisphosphate aldolases involved in metabolic conversion of carbohydrates for enzymes that do not contain metals. Further, our data identify candidate components of a high-affinity iron-uptake system, with several of the involved genes and domains originating from duplication events. A high genomic plasticity, as seen from the fraction of genes acquired through horizontal gene transfer, provides the platform for these complex adaptations to a low-iron world.
    Genome biology 07/2012; 13(7):R66. DOI:10.1186/gb-2012-13-7-r66 · 10.47 Impact Factor
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    ABSTRACT: Replacement of the native fermentation pathway in Escherichia coli B with a homo-ethanol pathway from Zymomonas mobilis (pdc and adhB genes) resulted in a 30 to 50% increase in growth rate and glycolytic flux during the anaerobic fermentation of xylose. Gene array analysis was used as a tool to investigate differences in expression levels for the 30 genes involved in xylose catabolism in the parent (strain B) and the engineered strain (KO11). Of the 4,290 total open reading frames, only 8% were expressed at a significantly higher level in KO11 (P < 0.05). In contrast, over half of the 30 genes involved in the catabolism of xylose to pyruvate were expressed at 1.5-fold- to 8-fold-higher levels in KO11. For 14 of the 30 genes, higher expression was statistically significant at the 95% confidence level (xylAB, xylE, xylFG, xylR, rpiA, rpiB, pfkA, fbaA, tpiA, gapA, pgk, and pykA) during active fermentation (6, 12, and 24 h). Values at single time points for only four of these genes (eno, fbaA, fbaB, and talA) were higher in strain B than in KO11. The relationship between changes in mRNA (cDNA) levels and changes in specific activities was verified for two genes (xylA and xylB) with good agreement. In KO11, expression levels and activities were threefold higher than in strain B for xylose isomerase (xylA) and twofold higher for xylulokinase (xylB). Increased expression of genes involved in xylose catabolism is proposed as the basis for the increase in growth rate and glycolytic flux in ethanologenic KO11.
    Journal of Bacteriology 05/2001; 183(10):2979-88. DOI:10.1128/JB.183.10.2979-2988.2001 · 2.69 Impact Factor
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