Cytosolic fructose-1,6-bisphosphatase: A key enzyme in the sucrose biosynthetic pathway

1993 ◽  
Vol 38 (1) ◽  
pp. 5-14 ◽  
Author(s):  
Jaleh Daie
Keyword(s):  
Biosynthetic Pathway ◽  
Fructose 1,6 Bisphosphatase ◽  
Key Enzyme

Disruption of genes for the enhanced biosynthesis of α-ketoglutarate in Corynebacterium glutamicum

2012 ◽  
Vol 58 (3) ◽  
pp. 278-286 ◽  
Author(s):  
Jae-Hyung Jo ◽  
Hye-Young Seol ◽  
Yun-Bom Lee ◽  
Min-Hong Kim ◽  
Hyung-Hwan Hyun ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Biosynthetic Pathway ◽  
Isocitrate Lyase ◽  
Glutamate Synthase ◽  
Flask Culture ◽  
Control Strain ◽  
Enhanced Production ◽  
Key Enzyme ◽  
Microbial Strains ◽  
Glyoxylate Pathway

The development of microbial strains for the enhanced production of α-ketoglutarate (α-KG) was investigated using a strain of Corynebacterium glutamicum that overproduces of l-glutamate, by disrupting three genes involved in the α-KG biosynthetic pathway. The pathways competing with the biosynthesis of α-KG were blocked by knocking out aceA (encoding isocitrate lyase, ICL), gdh (encoding glutamate dehydrogenase, l-gluDH), and gltB (encoding glutamate synthase or glutamate-2-oxoglutarate aminotransferase, GOGAT). The strain with aceA, gltB, and gdh disrupted showed reduced ICL activity and no GOGAT and l-gluDH activities, resulting in up to 16-fold more α-KG production than the control strain in flask culture. These results suggest that l-gluDH is the key enzyme in the conversion of α-KG to l-glutamate; therefore, prevention of this step could promote α-KG accumulation. The inactivation of ICL leads the carbon flow to α-KG by blocking the glyoxylate pathway. However, the disruption of gltB did not affect the biosynthesis of α-KG. Our results can be applied in the industrial production of α-KG by using C. glutamicum as producer.

scholarly journals The biosynthetic pathway of potato solanidanes diverged from that of spirosolanes due to evolution of a dioxygenase

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ryota Akiyama ◽  
Bunta Watanabe ◽  
Masaru Nakayasu ◽  
Hyoung Jae Lee ◽  
Junpei Kato ◽  
...  
Keyword(s):  
Solanum Tuberosum ◽  
Solanum Lycopersicum ◽  
Biosynthetic Pathway ◽  
Potato Breeding ◽  
Chemical Diversity ◽  
Evolutionary Divergence ◽  
Food Crop ◽  
Common Pathway ◽  
Structural Differences ◽  
Key Enzyme

AbstractPotato (Solanum tuberosum), a worldwide major food crop, produces the toxic, bitter tasting solanidane glycoalkaloids α-solanine and α-chaconine. Controlling levels of glycoalkaloids is an important focus on potato breeding. Tomato (Solanum lycopersicum) contains a bitter spirosolane glycoalkaloid, α-tomatine. These glycoalkaloids are biosynthesized from cholesterol via a partly common pathway, although the mechanisms giving rise to the structural differences between solanidane and spirosolane remained elusive. Here we identify a 2-oxoglutarate dependent dioxygenase, designated as DPS (Dioxygenase for Potato Solanidane synthesis), that is a key enzyme for solanidane glycoalkaloid biosynthesis in potato. DPS catalyzes the ring-rearrangement from spirosolane to solanidane via C-16 hydroxylation. Evolutionary divergence of spirosolane-metabolizing dioxygenases contributes to the emergence of toxic solanidane glycoalkaloids in potato and the chemical diversity in Solanaceae.

scholarly journals Bornyl Diphosphate Synthase From Cinnamomum burmanni and Its Application for (+)-Borneol Biosynthesis in Yeast

2021 ◽  
Vol 9 ◽  
Author(s):  
Rui Ma ◽  
Ping Su ◽  
Juan Guo ◽  
Baolong Jin ◽  
Qing Ma ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Biosynthetic Pathway ◽  
Main Product ◽  
Microbial Fermentation ◽  
Biosynthesis Pathway ◽  
Analgesic Effects ◽  
Pathway Reconstruction ◽  
Key Enzyme ◽  
Shake Flasks

(+)-Borneol is a desirable monoterpenoid with effective anti-inflammatory and analgesic effects that is known as soft gold. (+)-bornyl diphosphate synthase is the key enzyme in the (+)-borneol biosynthesis pathway. Despite several reported (+)-bornyl diphosphate synthase genes, relatively low (+)-borneol production hinders the attempts to synthesize it using microbial fermentation. Here, we identified the highly specific (+)-bornyl diphosphate synthase CbTPS1 from Cinnamomum burmanni. An in vitro assay showed that (+)-borneol was the main product of CbTPS1 (88.70% of the total products), and the Km value was 5.11 ± 1.70 μM with a kcat value of 0.01 s–1. Further, we reconstituted the (+)-borneol biosynthetic pathway in Saccharomyces cerevisiae. After tailored truncation and adding Kozak sequences, the (+)-borneol yield was improved by 96.33-fold to 2.89 mg⋅L–1 compared with the initial strain in shake flasks. This work is the first reported attempt to produce (+)-borneol by microbial fermentation. It lays a foundation for further pathway reconstruction and metabolic engineering production of this valuable natural monoterpenoid.

scholarly journals Crosstalk among Indoleamines, Neuropeptides and JH/20E in Regulation of Reproduction in the American Cockroach, Periplaneta americana

Insects ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 155 ◽  
Author(s):  
A. S. M. Kamruzzaman ◽  
Azam Mikani ◽  
Amr A. Mohamed ◽  
Azza M. Elgendy ◽  
Makio Takeda
Keyword(s):  
Oocyte Maturation ◽  
Biosynthetic Pathway ◽  
Periplaneta Americana ◽  
American Cockroach ◽  
Second Step ◽  
Double Stranded Rna ◽  
Vitellogenin Receptor ◽  
Genes Encoding ◽  
Key Enzyme ◽  
Indoleamine Metabolism

Although the regulation of vitellogenesis in insects has been mainly discussed in terms of ‘classical’ lipid hormones, juvenile hormone (JH), and 20-hydroxyecdysone (20E), recent data support the notion that this process must be adjusted in harmony with a nutritional input/reservoir and involvement of certain indoleamines and neuropeptides in regulation of such process. This study focuses on crosstalks among these axes, lipid hormones, monoamines, and neuropeptides in regulation of vitellogenesis in the American cockroach Periplaneta americana with novel aspects in the roles of arylalkylamine N-acetyltransferase (aaNAT), a key enzyme in indoleamine metabolism, and the enteroendocrine peptides; crustacean cardioactive peptide (CCAP) and short neuropeptide F (sNPF). Double-stranded RNA against aaNAT (dsRNAaaNAT) was injected into designated-aged females and the effects were monitored including the expressions of aaNAT itself, vitellogenin 1 and 2 (Vg1 and Vg2) and the vitellogenin receptor (VgR) mRNAs, oocyte maturation and changes in the hemolymph peptide concentrations. Effects of peptides application and 20E were also investigated. Injection of dsRNAaaNAT strongly suppressed oocyte maturation, transcription of Vg1, Vg2, VgR, and genes encoding JH acid- and farnesoate O-methyltransferases (JHAMT and FAMeT, respectively) acting in the JH biosynthetic pathway. However, it did not affect hemolymph concentrations of CCAP and sNPF. Injection of CCAP stimulated, while sNPF suppressed oocyte maturation and Vgs/VgR transcription, i.e., acting as allatomedins. Injection of CCAP promoted, while sNPF repressed ecdysteroid (20E) synthesis, particularly at the second step of Vg uptake. 20E also affected the JH biosynthetic pathway and Vg/VgR synthesis. The results revealed that on the course of vitellogenesis, JH- and 20E-mediated regulation occurs downstream to indoleamines- and peptides-mediated regulations. Intricate mutual interactions of these regulatory routes must orchestrate reproduction in this species at the highest potency.

scholarly journals High-Throughput Screen for Inhibitors of 1-Deoxy-D-Xylulose 5-Phosphate Reductoisomerase by Surrogate Ligand Competition

2003 ◽  
Vol 8 (3) ◽  
pp. 332-339 ◽  
Author(s):  
Elizabeth B. Gottlin ◽  
R. Edward Benson ◽  
Scott Conary ◽  
Brett Antonio ◽  
Kellie Duke ◽  
...  
Keyword(s):  
High Throughput ◽  
Binding Sites ◽  
Biosynthetic Pathway ◽  
Enzyme Assay ◽  
High Throughput Screen ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Biochemical Assays ◽  
Key Enzyme ◽  
Nadph Oxidation

1-Deoxy-D-xylulose 5-phosphate reductoisomerase (Dxr) is a key enzyme in a biosynthetic pathway for isoprenoids that is unique to eubacteria and plants. Dxr catalyzes the rearrangement and NADPH-dependent reduction of 1-deoxy-D-xylulose 5-phosphate to 2-C-methyl-D-erythritol 4-phosphate. The authors have purified Escherichia coli Dxr and devised a high-throughput screen (HTS) for compounds that bind to this enzyme at a functional site. Evidence is presented that the surrogate ligand directly binds or allosterically affects both the D-1-deoxyxylulose 5-phosphate (DXP) and NADPH binding sites. Compounds that bind at either or both sites that compete for binding with the surrogate ligand register as hits. The time-resolved fluorescence-based assay represents an improvement over the Dxr enzyme assay that relies on relatively insensitive measurements of NADPH oxidation. Screening 32,000 compounds from a diverse historical library, the authors obtained 89 potent inhibitors in the surrogate ligand competition assay. The results presented here suggest that peptide surrogate ligands may be useful in formatting HTS for proteins with difficult biochemical assays or targets of unknown function. ( Journal of Biomolecular Screening 2003:332-339)

scholarly journals The Gluconeogenic Enzyme Fructose-1,6-Bisphosphatase Is Dispensable for Growth of the Yeast Yarrowia lipolytica in Gluconeogenic Substrates

2008 ◽  
Vol 7 (10) ◽  
pp. 1742-1749 ◽  
Author(s):  
Raquel Jardón ◽  
Carlos Gancedo ◽  
Carmen-Lisset Flores
Keyword(s):  
Yarrowia Lipolytica ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Isocitrate Lyase ◽  
Carbon Sources ◽  
Subcellular Fractionation ◽  
Fructose 1,6 Bisphosphatase ◽  
Genes Encoding ◽  
Key Enzyme ◽  
Gluconeogenic Enzyme ◽  
Fructose 1,6 Bisphosphate

ABSTRACT The genes encoding gluconeogenic enzymes in the nonconventional yeast Yarrowia lipolytica were found to be differentially regulated. The expression of Y. lipolytica FBP1 (YlFBP1) encoding the key enzyme fructose-1,6-bisphosphatase was not repressed by glucose in contrast with the situation in other yeasts; however, this sugar markedly repressed the expression of YlPCK1, encoding phosphoenolpyruvate carboxykinase, and YlICL1, encoding isocitrate lyase. We constructed Y. lipolytica strains with two different disrupted versions of YlFBP1 and found that they grew much slower than the wild type in gluconeogenic carbon sources but that growth was not abolished as happens in most microorganisms. We attribute this growth to the existence of an alternative phosphatase with a high Km (2.3 mM) for fructose-1,6-bisphosphate. The gene YlFBP1 restored fructose-1,6-bisphosphatase activity and growth in gluconeogenic carbon sources to a Saccharomyces cerevisiae fbp1 mutant, but the introduction of the FBP1 gene from S. cerevisiae in the Ylfbp1 mutant did not produce fructose-1,6-bisphosphatase activity or growth complementation. Subcellular fractionation revealed the presence of fructose-1,6-bisphosphatase both in the cytoplasm and in the nucleus.

scholarly journals T-to-R switch of muscle fructose-1,6-bisphosphatase involves fundamental changes of secondary and quaternary structure

2016 ◽  
Vol 72 (4) ◽  
pp. 536-550 ◽  
Author(s):  
Jakub Barciszewski ◽  
Janusz Wisniewski ◽  
Robert Kolodziejczyk ◽  
Mariusz Jaskolski ◽  
Dariusz Rakus ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Catalytic Mechanism ◽  
Quaternary Structure ◽  
Homo Sapiens ◽  
Helical Structure ◽  
Smooth Transition ◽  
Muscle Enzyme ◽  
Enzymatic Function ◽  
Fructose 1,6 Bisphosphatase ◽  
Key Enzyme

Fructose-1,6-bisphosphatase (FBPase) catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate and is a key enzyme of gluconeogenesis and glyconeogenesis and, more generally, of the control of energy metabolism and glucose homeostasis. Vertebrates, and notablyHomo sapiens, express two FBPase isoforms. The liver isozyme is expressed mainly in gluconeogenic organs, where it functions as a regulator of glucose synthesis. The muscle isoform is expressed in all cells, and recent studies have demonstrated that its role goes far beyond the enzymatic function, as it can interact with various nuclear and mitochondrial proteins. Even in its enzymatic function, the muscle enzyme is different from the liver isoform, as it is 100-fold more susceptible to allosteric inhibition by AMP and this effect can be abrogated by complex formation with aldolase. All FBPases are homotetramers composed of two intimate dimers: the upper dimer and the lower dimer. They oscillate between two conformational states: the inactive T form when in complex with AMP, and the active R form. Parenthetically, it is noted that bacterial FBPases behave somewhat differently, and in the absence of allosteric activators exist in a tetramer–dimer equilibrium even at relatively high concentrations. [Hineset al.(2007),J. Biol. Chem.282, 11696–11704]. The T-to-R transition is correlated with the conformation of the key loop L2, which in the T form becomes `disengaged' and unable to participate in the catalytic mechanism. The T states of both isoforms are very similar, with a small twist of the upper dimer relative to the lower dimer. It is shown that at variance with the well studied R form of the liver enzyme, which is flat, the R form of the muscle enzyme is diametrically different, with a perpendicular orientation of the upper and lower dimers. The crystal structure of the muscle-isozyme R form shows that in this arrangement of the tetramer completely new protein surfaces are exposed that are most likely targets for the interactions with various cellular and enzymatic partners. The cruciform R structure is stabilized by a novel `leucine lock', which prevents the key residue, Asp187, from locking loop L2 in the disengaged conformation. In addition, the crystal structures of muscle FBPase in the T conformation with and without AMP strongly suggest that the T-to-R transition is a discrete jump rather than a shift of an equilibrium smooth transition through multiple intermediate states. Finally, using snapshots from three crystal structures of human muscle FBPase, it is conclusively demonstrated that the AMP-binding event is correlated with a β→α transition at the N-terminus of the protein and with the formation of a new helical structure.

scholarly journals Role of Ethylene in the Biosynthetic Pathway of Related-aroma Volatiles Derived from Fatty Acids in Oriental Sweet Melon

2016 ◽  
Vol 141 (4) ◽  
pp. 327-338 ◽  
Author(s):  
Yan Li ◽  
Hongyan Qi ◽  
Yazhong Jin ◽  
Xiaobin Tian ◽  
Linlin Sui ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Biosynthetic Pathway ◽  
Expression Patterns ◽  
Gene Families ◽  
Hydroperoxide Lyase ◽  
Straight Chain ◽  
Alcohol Acetyltransferase ◽  
Key Enzyme ◽  
Aroma Precursors

The catabolism of fatty acid (FA) is regarded as a key pathway of aroma volatile compounds in oriental sweet melon (Cucumis melo var. makuwa). In our research, two cultivars of oriental sweet melon, Caihong7 and Tianbao, were employed to illuminate which step of the biosynthetic pathway of aroma compounds could be regulated by ethylene (ETH). The role of ETH in determining the profiles of straight-chain aroma volatile compounds, levels of FA as aroma precursors, activities of aroma-related enzymes derived from FA pathway, and expression patterns of key enzymes were investigated. Overall, exogenous application of ETH increased the production rates of endogenous ETH and levels of FA. Compared with control, the level of straight-chain esters, especially the acetate, hexanoate, and hexyl esters, was significantly increased by ETH, whereas the content of alcohol and aldehyde reduced. In addition, the metabolism of free FA included linoleic acid (LA), linolenic acid (LeA), and oleic acid (OA) appeared to be ETH-dependent. The activities of lipoxygenase (LOX), alcohol dehydrogenase (ADH), and alcohol acetyltransferase (AAT) as well as the expression patterns of Cm-ADH1, Cm-ADH2, Cm-AAT1, and Cm-AAT4 were positively regulated by ETH. In contrast, hydroperoxide lyase (HPL) and Cm-AAT2 and Cm-AAT3 seemed to be independent of ETH modulation. These results suggested that the dissimilation of FA included LA, LeA, and OA into the acetate, hexanoate, and hexyl esters mainly through ETH regulating the LOX pathway by enhancing the expression of particular members of aroma-related key enzyme gene families as well as the activities of dehydrogenation and esterification.

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