scholarly journals l-Valine Production with Pyruvate Dehydrogenase Complex-Deficient Corynebacterium glutamicum

2007 ◽  
Vol 73 (7) ◽  
pp. 2079-2084 ◽  
Author(s):  
Bastian Blombach ◽  
Mark E. Schreiner ◽  
Jiří Holátko ◽  
Tobias Bartek ◽  
Marco Oldiges ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Maximum Yield ◽  
Cellular Growth ◽  
Acetohydroxyacid Synthase ◽  
Gene Encoding ◽  
Genes Encoding ◽  
Cell Densities ◽  
Dehydrogenase Complex

ABSTRACT Corynebacterium glutamicum was engineered for the production of l-valine from glucose by deletion of the aceE gene encoding the E1p enzyme of the pyruvate dehydrogenase complex and additional overexpression of the ilvBNCE genes encoding the l-valine biosynthetic enzymes acetohydroxyacid synthase, isomeroreductase, and transaminase B. In the absence of cellular growth, C. glutamicum ΔaceE showed a relatively high intracellular concentration of pyruvate (25.9 mM) and produced significant amounts of pyruvate, l-alanine, and l-valine from glucose as the sole carbon source. Lactate or acetate was not formed. Plasmid-bound overexpression of ilvBNCE in C. glutamicum ΔaceE resulted in an approximately 10-fold-lower intracellular pyruvate concentration (2.3 mM) and a shift of the extracellular product pattern from pyruvate and l-alanine towards l-valine. In fed-batch fermentations at high cell densities and an excess of glucose, C. glutamicum ΔaceE(pJC4ilvBNCE) produced up to 210 mM l-valine with a volumetric productivity of 10.0 mM h−1 (1.17 g l−1 h−1) and a maximum yield of about 0.6 mol per mol (0.4 g per g) of glucose.

scholarly journals Platform Engineering of Corynebacterium glutamicum with Reduced Pyruvate Dehydrogenase Complex Activity for Improved Production of l-Lysine, l-Valine, and 2-Ketoisovalerate

2013 ◽  
Vol 79 (18) ◽  
pp. 5566-5575 ◽  
Author(s):  
Jens Buchholz ◽  
Andreas Schwentner ◽  
Britta Brunnenkan ◽  
Christina Gabris ◽  
Simon Grimm ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Fed Batch ◽  
Complex Activity ◽  
Gene Encoding ◽  
Content Type ◽  
Genes Encoding ◽  
Cell Densities ◽  
Dehydrogenase Complex

ABSTRACTExchange of the nativeCorynebacterium glutamicumpromoter of theaceEgene, encoding the E1p subunit of the pyruvate dehydrogenase complex (PDHC), with mutateddapApromoter variants led to a series ofC. glutamicumstrains with gradually reduced growth rates and PDHC activities. Upon overexpression of thel-valine biosynthetic genesilvBNCE, all strains producedl-valine. Among these strains,C. glutamicum aceEA16 (pJC4ilvBNCE) showed the highest biomass and product yields, and thus it was further improved by additional deletion of thepqoandppcgenes, encoding pyruvate:quinone oxidoreductase and phosphoenolpyruvate carboxylase, respectively. In fed-batch fermentations at high cell densities,C. glutamicum aceEA16 Δpqo Δppc(pJC4ilvBNCE) produced up to 738 mM (i.e., 86.5 g/liter)l-valine with an overall yield (YP/S) of 0.36 mol per mol of glucose and a volumetric productivity (QP) of 13.6 mM per h [1.6 g/(liter × h)]. Additional inactivation of the transaminase B gene (ilvE) and overexpression ofilvBNCDinstead ofilvBNCEtransformed thel-valine-producing strain into a 2-ketoisovalerate producer, excreting up to 303 mM (35 g/liter) 2-ketoisovalerate with aYP/Sof 0.24 mol per mol of glucose and aQPof 6.9 mM per h [0.8 g/(liter × h)]. The replacement of theaceEpromoter by thedapA-A16 promoter in the twoC. glutamicuml-lysine producers DM1800 and DM1933 improved the production by 100% and 44%, respectively. These results demonstrate thatC. glutamicumstrains with reduced PDHC activity are an excellent platform for the production of pyruvate-derived products.

scholarly journals Metabolic Engineering of Corynebacterium glutamicum for 2-Ketoisovalerate Production

2010 ◽  
Vol 76 (24) ◽  
pp. 8053-8061 ◽  
Author(s):  
Felix S. Krause ◽  
Bastian Blombach ◽  
Bernhard J. Eikmanns
Keyword(s):  
Corynebacterium Glutamicum ◽  
Competitive Inhibition ◽  
Pyruvate Dehydrogenase Complex ◽  
Product Yield ◽  
Acetohydroxyacid Synthase ◽  
Gene Encoding ◽  
Keto Acids ◽  
Genes Encoding ◽  
Cell Densities ◽  
Branched Chain

ABSTRACT 2-Ketoisovalerate is used as a therapeutic agent, and a 2-ketoisovalerate-producing organism may serve as a platform for products deriving from this 2-keto acid. We engineered the wild type of Corynebacterium glutamicum for the growth-decoupled production of 2-ketoisovalerate from glucose by deletion of the aceE gene encoding the E1p subunit of the pyruvate dehydrogenase complex, deletion of the transaminase B gene ilvE, and additional overexpression of the ilvBNCD genes, encoding the l-valine biosynthetic enzymes acetohydroxyacid synthase (AHAS), acetohydroxyacid isomeroreductase, and dihydroxyacid dehydratase. 2-Ketoisovalerate production was further improved by deletion of the pyruvate:quinone oxidoreductase gene pqo. In fed-batch fermentations at high cell densities, the newly constructed strains produced up to 188 ± 28 mM (21.8 ± 3.2 g liter−1) 2-ketoisovalerate and showed a product yield of about 0.47 ± 0.05 mol per mol (0.3 ± 0.03 g per g) of glucose and a volumetric productivity of about 4.6 ± 0.6 mM (0.53 ± 0.07 g liter−1) 2-ketoisovalerate per h in the overall production phase. In studying the influence of the three branched-chain 2-keto acids 2-ketoisovalerate, 2-ketoisocaproate, and 2-keto-3-methylvalerate on the AHAS activity, we observed a competitive inhibition of the AHAS enzyme by 2-ketoisovalerate.

scholarly journals E1 Enzyme of the Pyruvate Dehydrogenase Complex in Corynebacterium glutamicum: Molecular Analysis of the Gene and Phylogenetic Aspects

2005 ◽  
Vol 187 (17) ◽  
pp. 6005-6018 ◽  
Author(s):  
Mark E. Schreiner ◽  
Diana Fiur ◽  
Jiří Holátko ◽  
Miroslav Pátek ◽  
Bernhard J. Eikmanns
Keyword(s):  
Corynebacterium Glutamicum ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Transcriptional Analysis ◽  
Oxidative Decarboxylation ◽  
Gene Encoding ◽  
Mutant Sequence ◽  
Genes Encoding ◽  
Translational Start ◽  
Dehydrogenase Complex

ABSTRACT The E1p enzyme is an essential part of the pyruvate dehydrogenase complex (PDHC) and catalyzes the oxidative decarboxylation of pyruvate with concomitant acetylation of the E2p enzyme within the complex. We analyzed the Corynebacterium glutamicum aceE gene, encoding the E1p enzyme, and constructed and characterized an E1p-deficient mutant. Sequence analysis of the C. glutamicum aceE gene and adjacent regions revealed that aceE is not flanked by genes encoding other enzymes of the PDHC. Transcriptional analysis revealed that aceE from C. glutamicum is monocistronic and that its transcription is initiated 121 nucleotides upstream of the translational start site. Inactivation of the chromosomal aceE gene led to the inability to grow on glucose and to the absence of PDHC and E1p activities, indicating that only a single E1p enzyme is present in C. glutamicum and that the PDHC is essential for the growth of this organism on carbohydrate substrates. Surprisingly, the E1p enzyme of C. glutamicum showed up to 51% identity to homodimeric E1p proteins from gram-negative bacteria but no similarity to E1 α- or β-subunits of heterotetrameric E1p enzymes which are generally assumed to be typical for gram-positives. To investigate the distribution of E1p enzymes in bacteria, we compiled and analyzed the phylogeny of 46 homodimeric E1p proteins and of 58 α-subunits of heterotetrameric E1p proteins deposited in public databases. The results revealed that the distribution of homodimeric and heterotetrameric E1p subunits in bacteria is not in accordance with the rRNA-based phylogeny of bacteria and is more heterogeneous than previously assumed.

scholarly journals Pyruvate dehydrogenase complex deficiency: updating the clinical, metabolic and mutational landscapes in a cohort of Portuguese patients

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Hana Pavlu-Pereira ◽  
Maria João Silva ◽  
Cristina Florindo ◽  
Sílvia Sequeira ◽  
Ana Cristina Ferreira ◽  
...  
Keyword(s):  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
In Silico Analysis ◽  
Psychomotor Retardation ◽  
Missense Mutations ◽  
Gene Encoding ◽  
Pathogenic Variants ◽  
Genes Encoding ◽  
Biochemical Analyses ◽  
Dehydrogenase Complex

Abstract Background The pyruvate dehydrogenase complex (PDC) catalyzes the irreversible decarboxylation of pyruvate into acetyl-CoA. PDC deficiency can be caused by alterations in any of the genes encoding its several subunits. The resulting phenotype, though very heterogeneous, mainly affects the central nervous system. The aim of this study is to describe and discuss the clinical, biochemical and genotypic information from thirteen PDC deficient patients, thus seeking to establish possible genotype–phenotype correlations. Results The mutational spectrum showed that seven patients carry mutations in the PDHA1 gene encoding the E1α subunit, five patients carry mutations in the PDHX gene encoding the E3 binding protein, and the remaining patient carries mutations in the DLD gene encoding the E3 subunit. These data corroborate earlier reports describing PDHA1 mutations as the predominant cause of PDC deficiency but also reveal a notable prevalence of PDHX mutations among Portuguese patients, most of them carrying what seems to be a private mutation (p.R284X). The biochemical analyses revealed high lactate and pyruvate plasma levels whereas the lactate/pyruvate ratio was below 16; enzymatic activities, when compared to control values, indicated to be independent from the genotype and ranged from 8.5% to 30%, the latter being considered a cut-off value for primary PDC deficiency. Concerning the clinical features, all patients displayed psychomotor retardation/developmental delay, the severity of which seems to correlate with the type and localization of the mutation carried by the patient. The therapeutic options essentially include the administration of a ketogenic diet and supplementation with thiamine, although arginine aspartate intake revealed to be beneficial in some patients. Moreover, in silico analysis of the missense mutations present in this PDC deficient population allowed to envisage the molecular mechanism underlying these pathogenic variants. Conclusion The identification of the disease-causing mutations, together with the functional and structural characterization of the mutant protein variants, allow to obtain an insight on the severity of the clinical phenotype and the selection of the most appropriate therapy.

scholarly journals Pyruvate dehydrogenase complex deficiency: updating the clinical, metabolic and mutational landscapes

2020 ◽  
Author(s):  
Hana Pavlu-Pereira ◽  
Maria João Silva ◽  
Cristina Florindo ◽  
Sílvia Sequeira ◽  
Ana Cristina Ferreira ◽  
...  
Keyword(s):  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
In Silico Analysis ◽  
Psychomotor Retardation ◽  
Missense Mutations ◽  
Gene Encoding ◽  
Pathogenic Variants ◽  
Genes Encoding ◽  
Biochemical Analyses ◽  
Dehydrogenase Complex

Abstract Background : Pyruvate dehydrogenase complex (PDC) catalyzes the irreversible decarboxylation of pyruvate into acetyl-CoA which ultimately generates ATP. PDC deficiency can be caused by alterations in any of the genes encoding its several subunits, and the resulting phenotype, though very heterogeneous, mainly affects the neuro-encephalic system. The aim of this study is to describe and discuss the clinic, metabolic and genotypic profiles of thirteen PDC deficient patients, thus seeking to establish possible genotype-phenotype correlations. Results : The mutational spectrum revealed that seven patients (54 %) carry mutations in the PDHA1 gene , encoding the E1α subunit, five patients (38 %) carry mutations in the PDHX gene, encoding the E3 binding protein, and the remaining patient (8 %) harbors mutations in the DLD gene, encoding the E3 subunit. These data corroborate PDHA1 mutations as the predominant cause of PDC deficiency, though revealing a notable prevalence of PDHX mutations among Portuguese patients, most of them carrying a seemingly private mutation (p.R284X). The biochemical analyses revealed high lactate and pyruvate plasma levels whereas de ratio L/P was under 16; enzymatic activities, when compared to control values, revealed to be independent from the genotype and ranged from 8.5% to 30% which may be considered a cut-off value for primary PDC deficiency. Concerning the clinical features, all patients displayed developmental delay/psychomotor retardation, the severity of which seems to correlate with the type and localization of the mutation carried by the patient. The therapeutic options essentially go through the administration of a ketogenic diet and supplementation with thiamine, although arginine aspartate intake revealed to be beneficial in some patients. Moreover, the in silico analysis of the missense mutations present in this PDC deficient population allowed to understand the molecular mechanism underlying these pathogenic variants. Conclusion : The identification of the disease-causing mutations, together with the functional and structural characterization of the mutant protein variants, allows to get insight on the severity of the clinical phenotype and the selection of the most appropriate therapy.

scholarly journals Expression and lipoylation in Escherichia coli of the inner lipoyl domain of the E2 component of the human pyruvate dehydrogenase complex

1993 ◽  
Vol 289 (1) ◽  
pp. 81-85 ◽  
Author(s):  
J Quinn ◽  
A G Diamond ◽  
A K Masters ◽  
D E Brookfield ◽  
N G Wallis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Structural Studies ◽  
Gene Encoding ◽  
E Coli ◽  
Inner Lipoyl Domain ◽  
Dehydrogenase Complex ◽  
Lipoyl Domain

The dihydrolipoamide acetyltransferase subunit (E2p) of mammalian pyruvate dehydrogenase complex has two highly conserved lipoyl domains each modified with a lipoyl cofactor bound in amide linkage to a specific lysine residue. A sub-gene encoding the inner lipoyl domain of human E2p has been over-expressed in Escherichia coli. Two forms of the domain have been purified, corresponding to lipoylated and non-lipoylated species. The apo-domain can be lipoylated in vitro with partially purified E. coli lipoate protein ligase, and the lipoylated domain can be reductively acetylated by human E1p (pyruvate dehydrogenase). Availability of the two forms will now allow detailed biochemical and structural studies of the human lipoyl domains.

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