scholarly journals Role of Acetyl Coenzyme A Synthesis and Breakdown in Alternative Carbon Source Utilization in Candida albicans

2008 ◽  
Vol 7 (10) ◽  
pp. 1733-1741 ◽  
Author(s):  
Aaron J. Carman ◽  
Slavena Vylkova ◽  
Michael C. Lorenz

ABSTRACT Acetyl coenzyme A (acetyl-CoA) is the central intermediate of the pathways required to metabolize nonfermentable carbon sources. Three such pathways, i.e., gluconeogenesis, the glyoxylate cycle, and β-oxidation, are required for full virulence in the fungal pathogen Candida albicans. These processes are compartmentalized in the cytosol, mitochondria, and peroxosomes, necessitating transport of intermediates across intracellular membranes. Acetyl-CoA is trafficked in the form of acetate by the carnitine shuttle, and we hypothesized that the enzymes that convert acetyl-CoA to/from acetate, i.e., acetyl-CoA hydrolase (ACH1) and acetyl-CoA synthetase (ACS1 and ACS2), would regulate alternative carbon utilization and virulence. We show that C. albicans strains depleted for ACS2 are unviable in the presence of most carbon sources, including glucose, acetate, and ethanol; these strains metabolize only fatty acids and glycerol, a substantially more severe phenotype than that of Saccharomyces cerevisiae acs2 mutants. In contrast, deletion of ACS1 confers no phenotype, though it is highly induced in the presence of fatty acids, perhaps explaining why acs2 mutants can utilize fatty acids. Strains lacking ACH1 have a mild growth defect on some carbon sources but are fully virulent in a mouse model of disseminated candidiasis. Both ACH1 and ACS2 complement mutations in their S. cerevisiae homolog. Together, these results show that acetyl-CoA metabolism and transport are critical for growth of C. albicans on a wide variety of nutrients. Furthermore, the phenotypic differences between mutations in these highly conserved genes in S. cerevisiae and C. albicans support recent findings that significant functional divergence exists even in fundamental metabolic pathways between these related yeasts.

2011 ◽  
Vol 10 (4) ◽  
pp. 547-555 ◽  
Author(s):  
Michael J. Hynes ◽  
Sandra L. Murray ◽  
Alex Andrianopoulos ◽  
Meryl A. Davis

ABSTRACTThe flow of carbon metabolites between cellular compartments is an essential feature of fungal metabolism. During growth on ethanol, acetate, or fatty acids, acetyl units must enter the mitochondrion for metabolism via the tricarboxylic acid cycle, and acetyl coenzyme A (acetyl-CoA) in the cytoplasm is essential for the biosynthetic reactions and for protein acetylation. Acetyl-CoA is produced in the cytoplasm by acetyl-CoA synthetase during growth on acetate and ethanol while β-oxidation of fatty acids generates acetyl-CoA in peroxisomes. The acetyl-carnitine shuttle in which acetyl-CoA is reversibly converted to acetyl-carnitine by carnitine acetyltransferase (CAT) enzymes is important for intracellular transport of acetyl units. In the filamentous ascomyceteAspergillus nidulans, a cytoplasmic CAT, encoded byfacC, is essential for growth on sources of cytoplasmic acetyl-CoA while a second CAT, encoded by theacuJgene, is essential for growth on fatty acids as well as acetate. We have shown that AcuJ contains an N-terminal mitochondrial targeting sequence and a C-terminal peroxisomal targeting sequence (PTS) and is localized to both peroxisomes and mitochondria, independent of the carbon source. Mislocalization of AcuJ to the cytoplasm does not result in loss of growth on acetate but prevents growth on fatty acids. Therefore, while mitochondrial AcuJ is essential for the transfer of acetyl units to mitochondria, peroxisomal localization is required only for transfer from peroxisomes to mitochondria. Peroxisomal AcuJ was not required for the import of acetyl-CoA into peroxisomes for conversion to malate by malate synthase (MLS), and export of acetyl-CoA from peroxisomes to the cytoplasm was found to be independent of FacC when MLS was mislocalized to the cytoplasm.


2010 ◽  
Vol 9 (7) ◽  
pp. 1039-1048 ◽  
Author(s):  
Michael J. Hynes ◽  
Sandra L. Murray

ABSTRACT Acetyl coenzyme A (CoA) is a central metabolite in carbon and energy metabolism and in the biosynthesis of cellular molecules. A source of cytoplasmic acetyl-CoA is essential for the production of fatty acids and sterols and for protein acetylation, including histone acetylation in the nucleus. In Saccharomyces cerevisiae and Candida albicans acetyl-CoA is produced from acetate by cytoplasmic acetyl-CoA synthetase, while in plants and animals acetyl-CoA is derived from citrate via ATP-citrate lyase. In the filamentous ascomycete Aspergillus nidulans, tandem divergently transcribed genes (aclA and aclB) encode the subunits of ATP-citrate lyase, and we have deleted these genes. Growth is greatly diminished on carbon sources that do not result in cytoplasmic acetyl-CoA, such as glucose and proline, while growth is not affected on carbon sources that result in the production of cytoplasmic acetyl-CoA, such as acetate and ethanol. Addition of acetate restores growth on glucose or proline, and this is dependent on facA, which encodes cytoplasmic acetyl-CoA synthetase, but not on the regulatory gene facB. Transcription of aclA and aclB is repressed by growth on acetate or ethanol. Loss of ATP-citrate lyase results in severe developmental effects, with the production of asexual spores (conidia) being greatly reduced and a complete absence of sexual development. This is in contrast to Sordaria macrospora, in which fruiting body formation is initiated but maturation is defective in an ATP-citrate lyase mutant. Addition of acetate does not repair these defects, indicating a specific requirement for high levels of cytoplasmic acetyl-CoA during differentiation. Complementation in heterokaryons between aclA and aclB deletions for all phenotypes indicates that the tandem gene arrangement is not essential.


2017 ◽  
Vol 5 (9) ◽  
Author(s):  
Miguel A. Matilla ◽  
Zulema Udaondo ◽  
Tino Krell ◽  
George P. C. Salmond

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.


2010 ◽  
Vol 192 (5) ◽  
pp. 1249-1258 ◽  
Author(s):  
Tobias J. Erb ◽  
Lena Frerichs-Revermann ◽  
Georg Fuchs ◽  
Birgit E. Alber

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.


2020 ◽  
Vol 21 (23) ◽  
pp. 8918
Author(s):  
Yevgeniya I. Shurubor ◽  
Arthur J. L. Cooper ◽  
Andrey B. Krasnikov ◽  
Elena P. Isakova ◽  
Yulia I. Deryabina ◽  
...  

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.


2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Di Zhu ◽  
Yifeng Wei ◽  
Jinyu Yin ◽  
Dazhi Liu ◽  
Ee Lui Ang ◽  
...  

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.


2014 ◽  
Vol 13 (12) ◽  
pp. 1472-1483 ◽  
Author(s):  
Luciano Galdieri ◽  
Tiantian Zhang ◽  
Daniella Rogerson ◽  
Rron Lleshi ◽  
Ales Vancura

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.


2014 ◽  
Vol 80 (8) ◽  
pp. 2536-2545 ◽  
Author(s):  
Aaron B. Hawkins ◽  
Michael W. W. Adams ◽  
Robert M. Kelly

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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