scholarly journals Properties of R-Citramalyl-Coenzyme A Lyase and Its Role in the Autotrophic 3-Hydroxypropionate Cycle of Chloroflexus aurantiacus

2007 ◽  
Vol 189 (7) ◽  
pp. 2906-2914 ◽  
Author(s):  
Silke Friedmann ◽  
Birgit E. Alber ◽  
Georg Fuchs
Keyword(s):  
Coenzyme A ◽  
Metabolic Process ◽  
Chloroflexus Aurantiacus ◽  
Acceptor Molecule ◽  
Acetyl Coa ◽  
Putative Gene ◽  
Acetyl Coenzyme A ◽  
Lyase Activity ◽  
Enzyme Functions ◽  
Aerobic Phototrophic Bacteria

ABSTRACT The autotrophic CO2 fixation pathway (3-hydroxypropionate cycle) in Chloroflexus aurantiacus results in the fixation of two molecules of bicarbonate into one molecule of glyoxylate. Glyoxylate conversion to the CO2 acceptor molecule acetyl-coenzyme A (CoA) requires condensation with propionyl-CoA (derived from one molecule of acetyl-CoA and one molecule of CO2) to β-methylmalyl-CoA, which is converted to citramalyl-CoA. Extracts of autotrophically grown cells contained both S- and R-citramalyl-CoA lyase activities, which formed acetyl-CoA and pyruvate. Pyruvate is taken out of the cycle and used for cellular carbon biosynthesis. Both the S- and R-citramalyl-CoA lyases were up-regulated severalfold during autotrophic growth. S-Citramalyl-CoA lyase activity was found to be due to l-malyl-CoA lyase/β-methylmalyl-CoA lyase. This promiscuous enzyme is involved in the CO2 fixation pathway, forms acetyl-CoA and glyoxylate from l-malyl-CoA, and condenses glyoxylate with propionyl-CoA to β-methylmalyl-CoA. R-Citramalyl-CoA lyase was further studied. Its putative gene was expressed and the recombinant protein was purified. This new enzyme belongs to the 3-hydroxy-3-methylglutaryl-CoA lyase family and is a homodimer with 34-kDa subunits that was 10-fold stimulated by adding Mg2 or Mn2+ ions and dithioerythritol. The up-regulation under autotrophic conditions suggests that the enzyme functions in the ultimate step of the acetyl-CoA regeneration route in C. aurantiacus. Genes similar to those involved in CO2 fixation in C. aurantiacus, including an R-citramalyl-CoA lyase gene, were found in Roseiflexus sp., suggesting the operation of the 3-hydroxypropionate cycle in this bacterium. Incomplete sets of genes were found in aerobic phototrophic bacteria and in the γ-proteobacterium Congregibacter litoralis. This may indicate that part of the reactions may be involved in a different metabolic process.

scholarly journals The Apparent Malate Synthase Activity of Rhodobacter sphaeroides Is Due to Two Paralogous Enzymes, (3S)-Malyl-Coenzyme A (CoA)/β-Methylmalyl-CoA Lyase and (3S)- Malyl-CoA Thioesterase

2010 ◽  
Vol 192 (5) ◽  
pp. 1249-1258 ◽  
Author(s):  
Tobias J. Erb ◽  
Lena Frerichs-Revermann ◽  
Georg Fuchs ◽  
Birgit E. Alber
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Coenzyme A ◽  
Glyoxylate Cycle ◽  
Condensation Reaction ◽  
Malate Synthase ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Claisen Condensation ◽  
Enzyme Functions ◽  
The Glyoxylate Cycle

ABSTRACT Assimilation of acetyl coenzyme A (acetyl-CoA) is an essential process in many bacteria that proceeds via the glyoxylate cycle or the ethylmalonyl-CoA pathway. In both assimilation strategies, one of the final products is malate that is formed by the condensation of acetyl-CoA with glyoxylate. In the glyoxylate cycle this reaction is catalyzed by malate synthase, whereas in the ethylmalonyl-CoA pathway the reaction is separated into two proteins: malyl-CoA lyase, a well-known enzyme catalyzing the Claisen condensation of acetyl-CoA with glyoxylate and yielding malyl-CoA, and an unidentified malyl-CoA thioesterase that hydrolyzes malyl-CoA into malate and CoA. In this study the roles of Mcl1 and Mcl2, two malyl-CoA lyase homologs in Rhodobacter sphaeroides, were investigated by gene inactivation and biochemical studies. Mcl1 is a true (3S)-malyl-CoA lyase operating in the ethylmalonyl-CoA pathway. Notably, Mcl1 is a promiscuous enzyme and catalyzes not only the condensation of acetyl-CoA and glyoxylate but also the cleavage of β-methylmalyl-CoA into glyoxylate and propionyl-CoA during acetyl-CoA assimilation. In contrast, Mcl2 was shown to be the sought (3S)-malyl-CoA thioesterase in the ethylmalonyl-CoA pathway, which specifically hydrolyzes (3S)-malyl-CoA but does not use β-methylmalyl-CoA or catalyze a lyase or condensation reaction. The identification of Mcl2 as thioesterase extends the enzyme functions of malyl-CoA lyase homologs that have been known only as “Claisen condensation” enzymes so far. Mcl1 and Mcl2 are both related to malate synthase, an enzyme which catalyzes both a Claisen condensation and thioester hydrolysis reaction.

scholarly journals Properties of Succinyl-Coenzyme A:l-Malate Coenzyme A Transferase and Its Role in the Autotrophic 3-Hydroxypropionate Cycle of Chloroflexus aurantiacus

2006 ◽  
Vol 188 (7) ◽  
pp. 2646-2655 ◽  
Author(s):  
Silke Friedmann ◽  
Astrid Steindorf ◽  
Birgit E. Alber ◽  
Georg Fuchs
Keyword(s):  
Escherichia Coli ◽  
Coenzyme A ◽  
Chloroflexus Aurantiacus ◽  
Class Iii ◽  
Terminal Amino Acid ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Coa Transferase ◽  
Terminal Amino ◽  
Terminal Amino Acid Sequence

ABSTRACT The 3-hydroxypropionate cycle has been proposed to operate as the autotrophic CO2 fixation pathway in the phototrophic bacterium Chloroflexus aurantiacus. In this pathway, acetyl coenzyme A (acetyl-CoA) and two bicarbonate molecules are converted to malate. Acetyl-CoA is regenerated from malyl-CoA by l-malyl-CoA lyase. The enzyme forming malyl-CoA, succinyl-CoA:l-malate coenzyme A transferase, was purified. Based on the N-terminal amino acid sequence of its two subunits, the corresponding genes were identified on a gene cluster which also contains the gene for l-malyl-CoA lyase, the subsequent enzyme in the pathway. Both enzymes were severalfold up-regulated under autotrophic conditions, which is in line with their proposed function in CO2 fixation. The two CoA transferase genes were cloned and heterologously expressed in Escherichia coli, and the recombinant enzyme was purified and studied. Succinyl-CoA:l-malate CoA transferase forms a large (αβ)n complex consisting of 46- and 44-kDa subunits and catalyzes the reversible reaction succinyl-CoA + l-malate → succinate + l-malyl-CoA. It is specific for succinyl-CoA as the CoA donor but accepts l-citramalate instead of l-malate as the CoA acceptor; the corresponding d-stereoisomers are not accepted. The enzyme is a member of the class III of the CoA transferase family. The demonstration of the missing CoA transferase closes the last gap in the proposed 3-hydroxypropionate cycle.

scholarly journals Genome Sequence of Serratia marcescens MSU97, a Plant-Associated Bacterium That Makes Multiple Antibiotics

2017 ◽  
Vol 5 (9) ◽  
Author(s):  
Miguel A. Matilla ◽  
Zulema Udaondo ◽  
Tino Krell ◽  
George P. C. Salmond
Keyword(s):  
Serratia Marcescens ◽  
Genome Sequence ◽  
Coenzyme A ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Content Type ◽  
Acetyl Coenzyme ◽  
Multiple Antibiotics

ABSTRACT Serratia marcescens MSU97 was isolated from the Guayana region of Venezuela due to its ability to suppress plant-pathogenic oomycetes. Here, we report the genome sequence of MSU97, which produces various antibiotics, including the bacterial acetyl-coenzyme A (acetyl-CoA) carboxylase inhibitor andrimid, the chlorinated macrolide oocydin A, and the red linear tripyrrole antibiotic prodigiosin.

Transcriptional regulation of acetyl coenzyme A carboxylase gene expression by tumor necrosis factor in 30A-5 preadipocytes

1989 ◽  
Vol 9 (3) ◽  
pp. 974-982
Author(s):  
M E Pape ◽  
K H Kim
Keyword(s):  
Tumor Necrosis Factor ◽  
Rna Polymerase ◽  
Tumor Necrosis ◽  
Transcriptional Control ◽  
Coenzyme A ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Mrna Accumulation ◽  
Acetyl Coenzyme A ◽  
Necrosis Factor

Acetyl coenzyme A (acetyl-CoA) carboxylase activity, amount, and mRNA levels increase during the differentiation of 30A-5 preadipocytes to adipocytes. Tumor necrosis factor (TNF) completely prevents this differentiation, with concomitant inhibition of acetyl-CoA carboxylase mRNA accumulation. To investigate the mechanisms by which TNF prevents acetyl-CoA carboxylase mRNA accumulation, we determined the effect of TNF on the transcription rate of the carboxylase gene and the half-life of carboxylase mRNA. Nuclear runoff transcription assays revealed no differences in the number of RNA polymerase molecules actively engaged in transcription of the acetyl-CoA carboxylase gene in preadipocytes, adipocytes, TNF-treated preadipocytes, or at any time during the course of differentiation. However, changes in adipsin, glycerophosphate dehydrogenase, and actin mRNAs, whose levels are also differentiation dependent, can be accounted for in part by changes in the number of polymerase complexes on their respective genes. To determine whether TNF caused a decrease in the stability of carboxylase RNA transcripts, we measured the rate of decay of prelabeled acetyl-CoA carboxylase mRNA. Control and TNF-treated cells showed no difference between the apparent half-lives of acetyl-CoA carboxylase mRNAs (9 h). However, the rate of acetyl-CoA carboxylase mRNA synthesis in vivo was decreased three- to fourfold in the presence of TNF. These data demonstrate that TNF prevents accumulation of acetyl-CoA carboxylase mRNA during preadipocyte differentiation by decreasing the rate of acetyl-CoA carboxylase gene transcription. However, transcriptional control is not due to a change in the number of RNA polymerase complexes actively engaged in carboxylase transcript elongation which could be measured by a number runoff assay. Instead, transcriptional control may be related to the rate at which RNA polymerase traverses the acetyl-CoA carboxylase gene.

scholarly journals Changes of Coenzyme A and Acetyl-Coenzyme A Concentrations in Rats after a Single-Dose Intraperitoneal Injection of Hepatotoxic Thioacetamide Are Not Consistent with Rapid Recovery

2020 ◽  
Vol 21 (23) ◽  
pp. 8918
Author(s):  
Yevgeniya I. Shurubor ◽  
Arthur J. L. Cooper ◽  
Andrey B. Krasnikov ◽  
Elena P. Isakova ◽  
Yulia I. Deryabina ◽  
...  
Keyword(s):  
Liver Function ◽  
Intraperitoneal Injection ◽  
Coenzyme A ◽  
Extended Period ◽  
Rat Tissues ◽  
Delayed Effect ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Acetyl Coenzyme ◽  
Small Biomolecules

Small biomolecules, such as coenzyme A (CoA) and acetyl coenzyme A (acetyl-CoA), play vital roles in the regulation of cellular energy metabolism. In this paper, we evaluated the delayed effect of the potent hepatotoxin thioacetamide (TAA) on the concentrations of CoA and acetyl-CoA in plasma and in different rat tissues. Administration of TAA negatively affects liver function and leads to the development of hepatic encephalopathy (HE). In our experiments, rats were administered a single intraperitoneal injection of TAA at doses of 200, 400, or 600 mg/kg. Plasma, liver, kidney, and brain samples were collected six days after the TAA administration, a period that has been suggested to allow for restoration of liver function. The concentrations of CoA and acetyl-CoA in the group of rats exposed to different doses of TAA were compared to those observed in healthy rats. The results obtained indicate that even a single administration of TAA to rats is sufficient to alter the physiological balance of CoA and acetyl-CoA in the plasma and tissues of rats for an extended period of time. The initial concentrations of CoA and acetyl-CoA were not restored even after the completion of the liver regeneration process.

scholarly journals A Pathway for Degradation of Uracil to Acetyl Coenzyme A in Bacillus megaterium

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Di Zhu ◽  
Yifeng Wei ◽  
Jinyu Yin ◽  
Dazhi Liu ◽  
Ee Lui Ang ◽  
...  
Keyword(s):  
Energy Source ◽  
Bacillus Megaterium ◽  
Coenzyme A ◽  
Catabolic Pathway ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Content Type ◽  
Biochemical Pathways ◽  
Acetyl Coenzyme

ABSTRACT Bacteria utilize diverse biochemical pathways for the degradation of the pyrimidine ring. The function of the pathways studied to date has been the release of nitrogen for assimilation. The most widespread of these pathways is the reductive pyrimidine catabolic pathway, which converts uracil into ammonia, carbon dioxide, and β-alanine. Here, we report the characterization of a β-alanine:pyruvate aminotransferase (PydD2) and an NAD+-dependent malonic semialdehyde dehydrogenase (MSDH) from a reductive pyrimidine catabolism gene cluster in Bacillus megaterium. Together, these enzymes convert β-alanine into acetyl coenzyme A (acetyl-CoA), a key intermediate in carbon and energy metabolism. We demonstrate the growth of B. megaterium in defined medium with uracil as its sole carbon and energy source. Homologs of PydD2 and MSDH are found in association with reductive pyrimidine pathway genes in many Gram-positive bacteria in the order Bacillales. Our study provides a basis for further investigations of the utilization of pyrimidines as a carbon and energy source by bacteria. IMPORTANCE Pyrimidine has wide occurrence in natural environments, where bacteria use it as a nitrogen and carbon source for growth. Detailed biochemical pathways have been investigated with focus mainly on nitrogen assimilation in the past decades. Here, we report the discovery and characterization of two important enzymes, PydD2 and MSDH, which constitute an extension for the reductive pyrimidine catabolic pathway. These two enzymes, prevalent in Bacillales based on our bioinformatics studies, allow stepwise conversion of β-alanine, a previous “end product” of the reductive pyrimidine degradation pathway, to acetyl-CoA as carbon and energy source.

scholarly journals Protein Acetylation and Acetyl Coenzyme A Metabolism in Budding Yeast

2014 ◽  
Vol 13 (12) ◽  
pp. 1472-1483 ◽  
Author(s):  
Luciano Galdieri ◽  
Tiantian Zhang ◽  
Daniella Rogerson ◽  
Rron Lleshi ◽  
Ales Vancura
Keyword(s):  
Cell Cycle Progression ◽  
Coenzyme A ◽  
Central Position ◽  
Metabolic State ◽  
Acetyl Coa ◽  
Cycle Progression ◽  
Acetyl Coenzyme A ◽  
Cell Functions ◽  
Physical Conditions ◽  
Acetyl Coenzyme

ABSTRACT Cells sense and appropriately respond to the physical conditions and availability of nutrients in their environment. This sensing of the environment and consequent cellular responses are orchestrated by a multitude of signaling pathways and typically involve changes in transcription and metabolism. Recent discoveries suggest that the signaling and transcription machineries are regulated by signals which are derived from metabolism and reflect the metabolic state of the cell. Acetyl coenzyme A (CoA) is a key metabolite that links metabolism with signaling, chromatin structure, and transcription. Acetyl-CoA is produced by glycolysis as well as other catabolic pathways and used as a substrate for the citric acid cycle and as a precursor in synthesis of fatty acids and steroids and in other anabolic pathways. This central position in metabolism endows acetyl-CoA with an important regulatory role. Acetyl-CoA serves as a substrate for lysine acetyltransferases (KATs), which catalyze the transfer of acetyl groups to the epsilon-amino groups of lysines in histones and many other proteins. Fluctuations in the concentration of acetyl-CoA, reflecting the metabolic state of the cell, are translated into dynamic protein acetylations that regulate a variety of cell functions, including transcription, replication, DNA repair, cell cycle progression, and aging. This review highlights the synthesis and homeostasis of acetyl-CoA and the regulation of transcriptional and signaling machineries in yeast by acetylation.

scholarly journals Conversion of 4-Hydroxybutyrate to Acetyl Coenzyme A and Its Anapleurosis in the Metallosphaera sedula 3-Hydroxypropionate/4-Hydroxybutyrate Carbon Fixation Pathway

2014 ◽  
Vol 80 (8) ◽  
pp. 2536-2545 ◽  
Author(s):  
Aaron B. Hawkins ◽  
Michael W. W. Adams ◽  
Robert M. Kelly
Keyword(s):  
Carbon Fixation ◽  
Coenzyme A ◽  
Flux Analysis ◽  
Central Metabolism ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Content Type ◽  
Metallosphaera Sedula ◽  
Acetyl Coenzyme ◽  
Coa Ligase

ABSTRACTThe extremely thermoacidophilic archaeonMetallosphaera sedula(optimum growth temperature, 73°C, pH 2.0) grows chemolithoautotrophically on metal sulfides or molecular hydrogen by employing the 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) carbon fixation cycle. This cycle adds two CO2molecules to acetyl coenzyme A (acetyl-CoA) to generate 4HB, which is then rearranged and cleaved to form two acetyl-CoA molecules. Previous metabolic flux analysis showed that two-thirds of central carbon precursor molecules are derived from succinyl-CoA, which is oxidized to malate and oxaloacetate. The remaining one-third is apparently derived from acetyl-CoA. As such, the steps beyond succinyl-CoA are essential for completing the carbon fixation cycle and for anapleurosis of acetyl-CoA. Here, the final four enzymes of the 3HP/4HB cycle, 4-hydroxybutyrate-CoA ligase (AMP forming) (Msed_0406), 4-hydroxybutyryl-CoA dehydratase (Msed_1321), crotonyl-CoA hydratase/(S)-3-hydroxybutyryl-CoA dehydrogenase (Msed_0399), and acetoacetyl-CoA β-ketothiolase (Msed_0656), were produced recombinantly inEscherichia coli, combinedin vitro, and shown to convert 4HB to acetyl-CoA. Metabolic pathways connecting CO2fixation and central metabolism were examined using a gas-intensive bioreactor system in whichM. sedulawas grown under autotrophic (CO2-limited) and heterotrophic conditions. Transcriptomic analysis revealed the importance of the 3HP/4HB pathway in supplying acetyl-CoA to anabolic pathways generating intermediates inM. sedulametabolism. The results indicated that flux between the succinate and acetyl-CoA branches in the 3HP/4HB pathway is governed by 4-hydroxybutyrate-CoA ligase, possibly regulated posttranslationally by the protein acetyltransferase (Pat)/Sir2-dependent system. Taken together, this work confirms the final four steps of the 3HP/4HB pathway, thereby providing the framework for examining connections between CO2fixation and central metabolism inM. sedula.

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