scholarly journals Acetyl Coenzyme A Analogues as Rationally Designed Inhibitors of Citrate Synthase

ChemBioChem ◽  
2019 ◽  
Vol 20 (9) ◽  
pp. 1174-1182 ◽  
Author(s):  
Davide Bello ◽  
Maria Grazia Rubanu ◽  
Nouchali Bandaranayaka ◽  
Jan P. Götze ◽  
Michael Bühl ◽  
...  
Keyword(s):  
Coenzyme A ◽  
Citrate Synthase ◽  
Acetyl Coenzyme A ◽  
Acetyl Coenzyme

scholarly journals Investigation of Carbon Metabolism in “Dehalococcoides ethenogenes” Strain 195 by Use of Isotopomer and Transcriptomic Analyses

2009 ◽  
Vol 191 (16) ◽  
pp. 5224-5231 ◽  
Author(s):  
Yinjie J. Tang ◽  
Shan Yi ◽  
Wei-Qin Zhuang ◽  
Stephen H. Zinder ◽  
Jay D. Keasling ◽  
...  
Keyword(s):  
Genome Annotation ◽  
Carbon Fixation ◽  
Coenzyme A ◽  
Citrate Synthase ◽  
Tricarboxylic Acid Cycle ◽  
Acetyl Coa ◽  
Experimental Conditions ◽  
Acetyl Coenzyme A ◽  
Acetyl Coenzyme ◽  
Dehalococcoides Ethenogenes

ABSTRACT Members of the genus “Dehalococcoides” are the only known microorganisms that can completely dechlorinate tetrachloroethene and trichloroethene to the innocuous end product, ethene. This study examines the central metabolism in “Dehalococcoides ethenogenes” strain 195 via 13C-labeled tracer experiments. Supported by the genome annotation and the transcript profile, isotopomer analysis of key metabolites clarifies ambiguities in the genome annotation and identifies an unusual biosynthetic pathway in strain 195. First, the 13C-labeling studies revealed that strain 195 contains complete amino acid biosynthesis pathways, even though current genome annotation suggests that several of these pathways are incomplete. Second, the tricarboxylic acid cycle of strain 195 is confirmed to be branched, and the Wood-Ljungdahl carbon fixation pathway is shown to not be functionally active under our experimental conditions; rather, CO2 is assimilated via two reactions, conversion of acetyl-coenzyme A (acetyl coenzyme A [acetyl-CoA]) to pyruvate catalyzed by pyruvate synthase (DET0724-0727) and pyruvate conversion to oxaloacetate via pyruvate carboxylase (DET0119-0120). Third, the 13C-labeling studies also suggested that isoleucine is synthesized from acetyl-CoA and pyruvate via citramalate synthase (CimA, EC 2.3.1.182), rather than from the common pathway via threonine ammonia-lyase (EC 4.3.1.19). Finally, evidence is presented that strain 195 may contain an undocumented citrate synthase (>95% Re-type stereospecific), i.e., a novel Re-citrate synthase that is apparently different from the one recently reported in Clostridium kluyveri.

scholarly journals Characterization of Citrate Synthase from Geobacter sulfurreducens and Evidence for a Family of Citrate Synthases Similar to Those of Eukaryotes throughout the Geobacteraceae

2005 ◽  
Vol 71 (7) ◽  
pp. 3858-3865 ◽  
Author(s):  
Daniel R. Bond ◽  
Tünde Mester ◽  
Camilla L. Nesbø ◽  
Andrea V. Izquierdo-Lopez ◽  
Frank L. Collart ◽  
...  
Keyword(s):  
Coenzyme A ◽  
Citrate Synthase ◽  
Geobacter Sulfurreducens ◽  
Acetate Metabolism ◽  
Acetyl Coenzyme A ◽  
Sedimentary Environments ◽  
Acetyl Coenzyme ◽  
The Family ◽  
Methylcitrate Synthase

ABSTRACT Members of the family Geobacteraceae are commonly the predominant Fe(III)-reducing microorganisms in sedimentary environments, as well as on the surface of energy-harvesting electrodes, and are able to effectively couple the oxidation of acetate to the reduction of external electron acceptors. Citrate synthase activity of these organisms is of interest due to its key role in acetate metabolism. Prior sequencing of the genome of Geobacter sulfurreducens revealed a putative citrate synthase sequence related to the citrate synthases of eukaryotes. All citrate synthase activity in G. sulfurreducens could be resolved to a single 49-kDa protein via affinity chromatography. The enzyme was successfully expressed at high levels in Escherichia coli with similar properties as the native enzyme, and kinetic parameters were comparable to related citrate synthases (k cat = 8.3 s−1; Km = 14.1 and 4.3 μM for acetyl coenzyme A and oxaloacetate, respectively). The enzyme was dimeric and was slightly inhibited by ATP (Ki = 1.9 mM for acetyl coenzyme A), which is a known inhibitor for many eukaryotic, dimeric citrate synthases. NADH, an allosteric inhibitor of prokaryotic hexameric citrate synthases, did not affect enzyme activity. Unlike most prokaryotic dimeric citrate synthases, the enzyme did not have any methylcitrate synthase activity. A unique feature of the enzyme, in contrast to citrate synthases from both eukaryotes and prokaryotes, was a lack of stimulation by K+ ions. Similar citrate synthase sequences were detected in a diversity of other Geobacteraceae members. This first characterization of a eukaryotic-like citrate synthase from a prokaryote provides new insight into acetate metabolism in Geobacteraceae members and suggests a molecular target for tracking the presence and activity of these organisms in the environment.

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