title: Re-citrate synthase from Clostridium kluyveri is phylogenetically related to homocitrate synthase and isopropylmalate synthase rather than to Si-citrate synthase.
abstract: The synthesis of citrate from acetyl-coenzyme A and oxaloacetate is catalyzed in most organisms by a Si-citrate synthase, which is Si-face stereospecific with respect to C-2 of oxaloacetate. However, in Clostridium kluyveri and some other strictly anaerobic bacteria, the reaction is catalyzed by a Re-citrate synthase, whose primary structure has remained elusive. We report here that Re-citrate synthase from C. kluyveri is the product of a gene predicted to encode isopropylmalate synthase. C. kluyveri is also shown to contain a gene for Si-citrate synthase, which explains why cell extracts of the organism always exhibit some Si-citrate synthase activity.
authors.affiliation: Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany.
authors.forename: Fuli
authors.initials: F
authors.lastname: Li
authors.forename: Christoph H
authors.initials: CH
authors.lastname: Hagemeier
authors.forename: Henning
authors.initials: H
authors.lastname: Seedorf
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gottschalk
authors.forename: Rudolf K
authors.initials: RK
authors.lastname: Thauer
mesh_terms: D015079:2-Isopropylmalate Synthase / Q000235:genetics* / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000235:genetics* / Q000378:metabolism; D002951:Citrates / Q000737:chemistry / Q000378:metabolism; D047010:Clostridium kluyveri / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D016680:Genome, Bacterial; D015394:Molecular Structure; D062907:Oxaloacetic Acid / Q000737:chemistry / Q000378:metabolism; D007652:Oxo-Acid-Lyases / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D013237:Stereoisomerism
chemical_list: D002951:Citrates; D062907:Oxaloacetic Acid; D002950:Citrate (si)-Synthase; D015079:2-Isopropylmalate Synthase; C021365:homocitrate synthase; D007652:Oxo-Acid-Lyases