scholarly journals Mitochondrial Carnitine-Dependent Acetyl Coenzyme A Transport Is Required for Normal Sexual and Asexual Development of the Ascomycete Gibberella zeae

2012 ◽  
Vol 11 (9) ◽  
pp. 1143-1153 ◽  
Author(s):  
Hokyoung Son ◽  
Kyunghun Min ◽  
Jungkwan Lee ◽  
Gyung Ja Choi ◽  
Jin-Cheol Kim ◽  
...  

ABSTRACTFungi have evolved efficient metabolic mechanisms for the exact temporal (developmental stages) and spatial (organelles) production of acetyl coenzyme A (acetyl-CoA). We previously demonstrated mechanistic roles of several acetyl-CoA synthetic enzymes, namely, ATP citrate lyase and acetyl-CoA synthetases (ACSs), in the plant-pathogenic fungusGibberella zeae. In this study, we characterized two carnitine acetyltransferases (CATs; CAT1 and CAT2) to obtain a better understanding of the metabolic processes occurring inG. zeae. We found that CAT1 functioned as an alternative source of acetyl-CoA required for lipid accumulation in anACS1deletion mutant. Moreover, deletion ofCAT1and/orCAT2resulted in various defects, including changes to vegetative growth, asexual/sexual development, trichothecene production, and virulence. Although CAT1 is associated primarily with peroxisomal CAT function, mislocalization experiments showed that the role of CAT1 in acetyl-CoA transport between the mitochondria and cytosol is important for sexual and asexual development inG. zeae. Taking these data together, we concluded thatG. zeaeCATs are responsible for facilitating the exchange of acetyl-CoA across intracellular membranes, particularly between the mitochondria and the cytosol, during various developmental stages.

2011 ◽  
Vol 10 (8) ◽  
pp. 1043-1052 ◽  
Author(s):  
Seunghoon Lee ◽  
Hokyoung Son ◽  
Jungkwan Lee ◽  
Kyunghun Min ◽  
Gyung Ja Choi ◽  
...  

ABSTRACTAcetyl coenzyme A (acetyl-CoA) is a crucial metabolite for energy metabolism and biosynthetic pathways and is produced in various cellular compartments with spatial and temporal precision. Our previous study on ATP citrate lyase (ACL) inGibberella zeaerevealed that ACL-dependent acetyl-CoA production is important for histone acetylation, especially in sexual development, but is not involved in lipid synthesis. In this study, we deleted additional acetyl-CoA synthetic genes, the acetyl-CoA synthetases (ACSgenesACS1andACS2), to identify alternative acetyl-CoA production mechanisms for ACL. TheACS1deletion resulted in a defect in sexual development that was mainly due to a reduction in 1-palmitoyl-2-oleoyl-3-linoleoyl-rac-glycerol production, which is required for perithecium development and maturation. Another ACS coding gene,ACS2, has accessorial functions forACS1and has compensatory functions forACLas a nuclear acetyl-CoA producer. This study showed that acetate is readily generated during the entire life cycle ofG. zeaeand has a pivotal role in fungal metabolism. Because ACSs are components of the pyruvate-acetaldehyde-acetate pathway, this fermentation process might have crucial roles in various physiological processes for filamentous fungi.


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.


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 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.


mBio ◽  
2014 ◽  
Vol 5 (6) ◽  
Author(s):  
Jens Nielsen

ABSTRACT The yeast Saccharomyces cerevisiae is a widely used cell factory for the production of fuels, chemicals, and pharmaceuticals. The use of this cell factory for cost-efficient production of novel fuels and chemicals requires high yields and low by-product production. Many industrially interesting chemicals are biosynthesized from acetyl coenzyme A (acetyl-CoA), which serves as a central precursor metabolite in yeast. To ensure high yields in production of these chemicals, it is necessary to engineer the central carbon metabolism so that ethanol production is minimized (or eliminated) and acetyl-CoA can be formed from glucose in high yield. Here the perspective of generating yeast platform strains that have such properties is discussed in the context of a major breakthrough with expression of a functional pyruvate dehydrogenase complex in the cytosol.


mBio ◽  
2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Tara N. Stuecker ◽  
Alex C. Tucker ◽  
Jorge C. Escalante-Semerena

ABSTRACTCoenzyme A (CoA) is essential for cellular chemistry in all forms of life. The pantothenate moiety of CoA is generated from the condensation of pantoate and β-alanine. β-Alanine is formed by decarboxylation ofl-aspartate catalyzed by PanD, a pyruvoyl enzyme that is synthesized by the cell as an inactive precursor (pro-PanD). Maturation of pro-PanD into PanD occurs via a self-cleavage event at residue Ser25, which forms the catalytic pyruvoyl moiety. We recently reported thatSalmonella entericaPanM was necessary for pro-PanD maturation, bothin vitroandin vivo. Notably, PanM is annotated as a Gcn5-likeN-acetyltransferase (GNAT), which suggested that lysine acetylation might be part of the mechanism of maturation. Here we show that PanM lacks acetyltransferase activity and that acetyl-CoA stimulates its activity. Results of experiments with nonhydrolyzable ethyl-CoA and genetically encoded acetyl-lysine-containing PanD support the conclusion that PanM-dependent pro-PanD maturation does not involve an acetyl transfer event. We also show that CoA binding to PanM is needed forin vivoactivity and that disruption of CoA binding prevents PanM from interacting with PanD. We conclude that PanM is a GNAT homologue that lost its acetyltransferase activity and evolved a new function as an acetyl-CoA sensor that can trigger the maturation of pro-PanD.IMPORTANCENε-lysine acetylation is increasingly being recognized as a widespread and important form of posttranslational regulation in bacteria. The acetyltransferases that catalyze these reactions are poorly characterized in bacteria. Based on annotation, most bacterial genomes contain several acetyltransferases, but the physiological roles of only a handful have been determined. Notably, a subset of putative acetyltransferases lack residues that are critical for activity in most biochemically characterized acetyltransferases. We show that one such putative acetyltransferase, PanM (formerly YhhK), lacks acetyltransferase activity but functions instead as an acetyl-coenzyme A (CoA) sensor. This work establishes the possibility that, like PanM, other putative acetyltransferases may have evolved new functions while retaining the ability to sense acetyl-CoA.


2014 ◽  
Vol 13 (12) ◽  
pp. 1530-1537 ◽  
Author(s):  
Cheryl P. Jones ◽  
Cheryl Ingram-Smith

ABSTRACTEntamoeba histolytica, an amitochondriate protozoan parasite that relies on glycolysis as a key pathway for ATP generation, has developed a unique extended PPi-dependent glycolytic pathway in which ADP-forming acetyl-coenzyme A (CoA) synthetase (ACD; acetate:CoA ligase [ADP-forming]; EC 6.2.1.13) converts acetyl-CoA to acetate to produce additional ATP and recycle CoA. We characterized the recombinantE. histolyticaACD and found that the enzyme is bidirectional, allowing it to potentially play a role in ATP production or in utilization of acetate. In the acetate-forming direction, acetyl-CoA was the preferred substrate and propionyl-CoA was used with lower efficiency. In the acetyl-CoA-forming direction, acetate was the preferred substrate, with a lower efficiency observed with propionate. The enzyme can utilize both ADP/ATP and GDP/GTP in the respective directions of the reaction. ATP and PPiwere found to inhibit the acetate-forming direction of the reaction, with 50% inhibitory concentrations of 0.81 ± 0.17 mM (mean ± standard deviation) and 0.75 ± 0.20 mM, respectively, which are both in the range of their physiological concentrations. ATP and PPidisplayed mixed inhibition versus each of the three substrates, acetyl-CoA, ADP, and phosphate. This is the first example of regulation of ACD enzymatic activity, and possible roles for this regulation are discussed.


2017 ◽  
Vol 83 (16) ◽  
Author(s):  
Ellinor D. Carlson ◽  
Eleftherios T. Papoutsakis

ABSTRACT With recent advances in synthetic biology, CO2 could be utilized as a carbon feedstock by native or engineered organisms, assuming the availability of electrons. Two key enzymes used in autotrophic CO2 fixation are the CO dehydrogenase (CODH) and acetyl coenzyme A (acetyl-CoA) synthase (ACS), which form a bifunctional heterotetrameric complex. The CODH/ACS complex can reversibly catalyze CO2 to CO, effectively enabling a biological water-gas shift reaction at ambient temperatures and pressures. The CODH/ACS complex is part of the Wood-Ljungdahl pathway (WLP) used by acetogens to fix CO2, and it has been well characterized in native hosts. So far, only a few recombinant CODH/ACS complexes have been expressed in heterologous hosts, none of which demonstrated in vivo CO2 reduction. Here, functional expression of the Clostridium carboxidivorans CODH/ACS complex is demonstrated in the solventogen Clostridium acetobutylicum, which was engineered to express CODH alone or together with the ACS. Both strains exhibited CO2 reduction and CO oxidation activities. The CODH reactions were interrogated using isotopic labeling, thus verifying that CO was a direct product of CO2 reduction, and vice versa. CODH apparently uses a native C. acetobutylicum ferredoxin as an electron carrier for CO2 reduction. Heterologous CODH activity depended on actively growing cells and required the addition of nickel, which is inserted into CODH without the need to express the native Ni insertase protein. Increasing CO concentrations in the gas phase inhibited CODH activity and altered the metabolite profile of the CODH-expressing cells. This work provides the foundation for engineering a complete and functional WLP in nonnative host organisms. IMPORTANCE Functional expression of CO dehydrogenase (CODH) from Clostridium carboxidivorans was demonstrated in C. acetobutylicum, which is natively incapable of CO2 fixation. The expression of CODH, alone or together with the C. carboxidivorans acetyl-CoA synthase (ACS), enabled C. acetobutylicum to catalyze both CO2 reduction and CO oxidation. Importantly, CODH exhibited activity in both the presence and absence of ACS. 13C-tracer studies confirmed that the engineered C. acetobutylicum strains can reduce CO2 to CO and oxidize CO during growth on glucose.


2016 ◽  
Vol 199 (4) ◽  
Author(s):  
Farshad Borjian ◽  
Jing Han ◽  
Jing Hou ◽  
Hua Xiang ◽  
Jan Zarzycki ◽  
...  

ABSTRACT Haloarchaea are extremely halophilic heterotrophic microorganisms belonging to the class Halobacteria (Euryarchaeota). Almost half of the haloarchaea possesses the genes coding for enzymes of the methylaspartate cycle, a recently discovered anaplerotic acetate assimilation pathway. In this cycle, the enzymes of the tricarboxylic acid cycle together with the dedicated enzymes of the methylaspartate cycle convert two acetyl coenzyme A (acetyl-CoA) molecules to malate. The methylaspartate cycle involves two reactions catalyzed by homologous enzymes belonging to the CitE-like enzyme superfamily, malyl-CoA lyase/thioesterase (haloarchaeal malate synthase [hMS]; Hah_2476 in Haloarcula hispanica) and β-methylmalyl-CoA lyase (haloarchaeal β-methylmalyl-CoA lyase [hMCL]; Hah_1341). Although both enzymes catalyze the same reactions, hMS was previously proposed to preferentially catalyze the formation of malate from acetyl-CoA and glyoxylate (malate synthase activity) and hMCL was proposed to primarily cleave β-methylmalyl-CoA to propionyl-CoA and glyoxylate. Here we studied the physiological functions of these enzymes during acetate assimilation in H. hispanica by using biochemical assays of the wild type and deletion mutants. Our results reveal that the main physiological function of hMS is malyl-CoA (not malate) formation and that hMCL catalyzes a β-methylmalyl-CoA lyase reaction in vivo. The malyl-CoA thioesterase activities of both enzymes appear to be not essential for growth on acetate. Interestingly, despite the different physiological functions of hMS and hMCL, structural comparisons predict that these two proteins have virtually identical active sites, thus highlighting the need for experimental validation of their catalytic functions. Our results provide further proof of the operation of the methylaspartate cycle and indicate the existence of a distinct, yet-to-be-discovered malyl-CoA thioesterase in haloarchaea. IMPORTANCE Acetate is one of the most important substances in natural environments. The activated form of acetate, acetyl coenzyme A (acetyl-CoA), is the high-energy intermediate at the crossroads of central metabolism: its oxidation generates energy for the cell, and about a third of all biosynthetic fluxes start directly from acetyl-CoA. Many organic compounds enter the central carbon metabolism via this key molecule. To sustain growth on acetyl-CoA-generating compounds, a dedicated assimilation (anaplerotic) pathway is required. The presence of an anaplerotic pathway is a prerequisite for growth in many environments, being important for environmentally, industrially, and clinically important microorganisms. Here we studied specific reactions of a recently discovered acetate assimilation pathway, the methylaspartate cycle, functioning in extremely halophilic archaea.


2014 ◽  
Vol 58 (10) ◽  
pp. 6122-6132 ◽  
Author(s):  
Manchi C. M. Reddy ◽  
Ardala Breda ◽  
John B. Bruning ◽  
Mukul Sherekar ◽  
Spandana Valluru ◽  
...  

ABSTRACTInMycobacterium tuberculosis, the carboxylation of acetyl coenzyme A (acetyl-CoA) to produce malonyl-CoA, a building block in long-chain fatty acid biosynthesis, is catalyzed by two enzymes working sequentially: a biotin carboxylase (AccA) and a carboxyltransferase (AccD). While the exact roles of the three different biotin carboxylases (AccA1 to -3) and the six carboxyltransferases (AccD1 to -6) inM. tuberculosisare still not clear, AccD6 in complex with AccA3 can synthesize malonyl-CoA from acetyl-CoA. A series of 10 herbicides that target plant acetyl-CoA carboxylases (ACC) were tested for inhibition of AccD6 and for whole-cell activity againstM. tuberculosis. From the tested herbicides, haloxyfop, an arylophenoxypropionate, showedin vitroinhibition ofM. tuberculosisAccD6, with a 50% inhibitory concentration (IC50) of 21.4 ± 1 μM. Here, we report the crystal structures ofM. tuberculosisAccD6 in the apo form (3.0 Å) and in complex with haloxyfop-R(2.3 Å). The structure ofM. tuberculosisAccD6 in complex with haloxyfop-Rshows two molecules of the inhibitor bound on each AccD6 subunit. These results indicate the potential for developing novel therapeutics for tuberculosis based on herbicides with low human toxicity.


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