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dc.contributor.authorCrousilles, Audrey
dc.contributor.authorDolan, Stephen
dc.contributor.authorBrear, Paul
dc.contributor.authorChirgadze, Dima
dc.contributor.authorWelch, Martin
dc.date.accessioned2018-11-08T00:30:55Z
dc.date.available2018-11-08T00:30:55Z
dc.date.issued2018-09-14
dc.identifier.issn0021-9258
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/284751
dc.description.abstractThe glyoxylate shunt bypasses the oxidative decarboxylation steps of the tricarboxylic acid (TCA) cycle, thereby conserving carbon skeletons for gluconeogenesis and biomass production. In Escherichia coli, carbon flux is redirected through the first enzyme of the glyoxylate shunt, isocitrate lyase (ICL), following phosphorylation and inactivation of the TCA cycle enzyme, isocitrate dehydrogenase (ICD), by the kinase/phosphatase, AceK. In contrast, mycobacterial species lack AceK and employ a phosphorylation-insensitive isocitrate dehydrogenase (IDH), which is allosterically activated by the product of ICL activity, glyoxylate. However, Pseudomonas aeruginosa expresses IDH, ICD, ICL, and AceK, raising the question of how these enzymes are regulated to ensure proper flux distribution between the competing pathways. Here, we present the structure, kinetics, and regulation of ICL, IDH, and ICD from P. aeruginosa We found that flux partitioning is coordinated through reciprocal regulation of these enzymes, linking distribution of carbon flux to the availability of the key gluconeogenic precursors, oxaloacetate and pyruvate. Specifically, a greater abundance of these metabolites activated IDH and inhibited ICL, leading to increased TCA cycle flux. Regulation was also exerted through AceK-dependent phosphorylation of ICD; high levels of acetyl-CoA (which would be expected to accumulate when oxaloacetate is limiting) stimulated the kinase activity of AceK, whereas high levels of oxaloacetate stimulated its phosphatase activity. In summary, the TCA cycle-glyoxylate shunt branch point in P. aeruginosa has a complex enzymology that is profoundly different from those in other species characterized to date. Presumably, this reflects its predilection for consuming fatty acids, especially during infection scenarios.
dc.format.mediumPrint-Electronic
dc.languageeng
dc.publisherElsevier BV
dc.subjectPseudomonas aeruginosa
dc.subjectEscherichia coli
dc.subjectGlyoxylates
dc.subjectAcetyl Coenzyme A
dc.subjectIsocitrate Lyase
dc.subjectIsocitrate Dehydrogenase
dc.subjectCrystallography, X-Ray
dc.subjectCitric Acid Cycle
dc.subjectDecarboxylation
dc.subjectGluconeogenesis
dc.subjectPhosphorylation
dc.subjectKinetics
dc.subjectOxaloacetic Acid
dc.titleGluconeogenic precursor availability regulates flux through the glyoxylate shunt in Pseudomonas aeruginosa.
dc.typeArticle
prism.endingPage14269
prism.issueIdentifier37
prism.publicationDate2018
prism.publicationNameJ Biol Chem
prism.startingPage14260
prism.volume293
dc.identifier.doi10.17863/CAM.32123
dcterms.dateAccepted2018-07-20
rioxxterms.versionofrecord10.1074/jbc.RA118.004514
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserved
rioxxterms.licenseref.startdate2018-09
dc.contributor.orcidDolan, Stephen [0000-0002-7391-2137]
dc.contributor.orcidChirgadze, Dima [0000-0001-9942-0993]
dc.contributor.orcidWelch, Martin [0000-0003-3646-1733]
dc.identifier.eissn1083-351X
rioxxterms.typeJournal Article/Review
pubs.funder-project-idBiotechnology and Biological Sciences Research Council (BB/M019411/1)
rioxxterms.freetoread.startdate2019-09-30


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