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 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 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 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:Quinone Oxidoreductase in Corynebacterium glutamicum: Molecular Analysis of the pqo Gene, Significance of the Enzyme, and Phylogenetic Aspects

2006 ◽  
Vol 188 (4) ◽  
pp. 1341-1350 ◽  
Author(s):  
Mark E. Schreiner ◽  
Christian Riedel ◽  
Jiři Holátko ◽  
Miroslav Pátek ◽  
Bernhard J. Eikmanns
Keyword(s):  
Amino Acid ◽  
Corynebacterium Glutamicum ◽  
Pyruvate Dehydrogenase ◽  
Acid Production ◽  
Pyruvate Dehydrogenase Complex ◽  
Wide Distribution ◽  
Oxidative Decarboxylation ◽  
Amino Acid Production ◽  
Acetohydroxy Acid Synthase ◽  
Dehydrogenase Complex

ABSTRACT Corynebacterium glutamicum recently has been shown to possess pyruvate:quinone oxidoreductase (PQO), catalyzing the oxidative decarboxylation of pyruvate to acetate and CO2 with a quinone as the electron acceptor. Here, we analyze the expression of the C. glutamicum pqo gene, investigate the relevance of the PQO enzyme for growth and amino acid production, and perform phylogenetic studies. Expression analyses revealed that transcription of pqo is initiated 45 bp upstream of the translational start site and that it is organized in an operon together with genes encoding a putative metal-activated pyridoxal enzyme and a putative activator protein. Inactivation of the chromosomal pqo gene led to the absence of PQO activity; however, growth and amino acid production were not affected under either condition tested. Introduction of plasmid-bound pqo into a pyruvate dehydrogenase complex-negative C. glutamicum strain partially relieved the growth phenotype of this mutant, indicating that high PQO activity can compensate for the function of the pyruvate dehydrogenase complex. To investigate the distribution of PQO enzymes in prokaryotes and to clarify the relationship between PQO, pyruvate oxidase (POX), and acetohydroxy acid synthase enzymes, we compiled and analyzed the phylogeny of respective proteins deposited in public databases. The analyses revealed a wide distribution of PQOs among prokaryotes, corroborated the hypothesis of a common ancestry of the three enzymes, and led us to propose that the POX enzymes of Lactobacillales were derived from a PQO.

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 Analysis of Cytadherence-Deficient, GapA-NegativeMycoplasma gallisepticum Strain R

2000 ◽  
Vol 68 (12) ◽  
pp. 6643-6649 ◽  
Author(s):  
L. Papazisi ◽  
K. E. Troy ◽  
T. S. Gorton ◽  
X. Liao ◽  
S. J. Geary
Keyword(s):  
Shuttle Vector ◽  
Phenotypic Expression ◽  
Mycoplasma Genitalium ◽  
Transcriptional Analysis ◽  
Start Codon ◽  
Wild Type ◽  
Gene Encoding ◽  
Genes Encoding ◽  
Low Passage ◽  
Translational Start

ABSTRACT Comparison of the phenotypic expression of Mycoplasma gallisepticum strain R low (passage 15) to that of strain R high (passage 164) revealed that three proteins, i.e., the cytadhesin molecule GapA, a 116-kDa protein (p116), and a 45-kDa protein (p45), are missing in strain R high. Sequence analysis confirmed that the insertion of an adenine 105 bp downstream of the gapAtranslational start codon resulted in premature termination of translation in R high. A second adenine insertion had also occurred at position 907. Restoration of expression of wild-type gapAin R high (clone designated GT5) allowed us to evaluate the extent to which the diminished cytadherence capacity could be attributed to GapA alone. The results indicated that GT5 attached to the same limited extent as the parental R high, from which it was derived. The cytadherence capability of the parental R high was not restored solely by gapA complementation alone, indicating that either p116 or p45 or both may play a role in the overall cytadherence process. The gene encoding p116 was found to be immediately downstream ofgapA in the same operon and was designatedcrmA. This gene exhibited striking homology to genes encoding molecules with cytadhesin-related functions in bothMycoplasma pneumoniae and Mycoplasma genitalium. Transcriptional analysis revealed thatcrmA is not transcribed in R high. We are currently constructing a shuttle vector containing both the wild-typegapA and crmA for transformation into R high to assess the role of CrmA in the cytadherence process.

On The Unique Structural Organization of the Saccharomyces Cerevisiae Pyruvate Dehydrogenase Complex

1998 ◽  
Vol 4 (S2) ◽  
pp. 954-955
Author(s):  
James K. Stoops ◽  
Z. Hong Zhou ◽  
John P. Schroeter ◽  
Steven J. Kolodziej ◽  
R. Holland Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Saccharomyces Cerevisiae ◽  
Pyruvate Dehydrogenase ◽  
Structural Organization ◽  
Pyruvate Dehydrogenase Complex ◽  
The Other ◽  
Oxidative Decarboxylation ◽  
Multienzyme Complex ◽  
The Core ◽  
Dehydrogenase Complex

Dihydrohpoamide acetyl transferase (E2), a catalytic and structural component of a multienzyme complex that catalyzes the oxidative decarboxylation of pyruvate, forms the central core to which the other components are bound. We have utilized protein engineering and 3-D electron microscopy to study the structural organization of the largest multienzyme complex known (Mr ∼ 107). The structures of the truncated 60-mer core (tE2) and complexes of the tE2 associated with a binding protein (BP), and the BP associated with its dihydrohpoamide dehydrogenase (BP'E3) and the intact E2 associated with BP and the pyruvate dehydrogenase (E1) were determined (Figs. 1 and 2). The tE2 core is a pentagonal dodecahedron consisting of 20 cone-shaped trimers interconnected by 30 bridges.Previous studies have given rise to the generally accepted belief that BP and BP'E3 components are bound on the outside of the E2 scaffold and that E1 is similarly bound to the core in variable positions by flexible tethers.

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