title: Reaction kinetic analysis of the 3-hydroxypropionate/4-hydroxybutyrate CO2fixation cycle in extremely thermoacidophilic archaea.
abstract: The 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) cycle fixes CO2in extremely thermoacidophilic archaea and holds promise for metabolic engineering because of its thermostability and potentially rapid pathway kinetics. A reaction kinetics model was developed to examine the biological and biotechnological attributes of the 3HP/4HB cycle as it operates in Metallosphaera sedula, based on previous information as well as on kinetic parameters determined here for recombinant versions of five of the cycle enzymes (malonyl-CoA/succinyl-CoA reductase, 3-hydroxypropionyl-CoA synthetase, 3-hydroxypropionyl-CoA dehydratase, acryloyl-CoA reductase, and succinic semialdehyde reductase). The model correctly predicted previously observed features of the cycle: the 35-65% split of carbon flux through the acetyl-CoA and succinate branches, the high abundance and relative ratio of acetyl-CoA/propionyl-CoA carboxylase (ACC) and MCR, and the significance of ACC and hydroxybutyryl-CoA synthetase (HBCS) as regulated control points for the cycle. The model was then used to assess metabolic engineering strategies for incorporating CO2into chemical intermediates and products of biotechnological importance: acetyl-CoA, succinate, and 3-hydroxypropionate.
authors: Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, United States.
authors: Andrew J
authors: AJ
authors: Loder
authors: Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, United States.
authors: Yejun
authors: Y
authors: Han
authors: Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, United States.
authors: Aaron B
authors: AB
authors: Hawkins
authors: Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, United States.
authors: Hong
authors: H
authors: Lian
authors: Dept. of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, United States.
authors: Gina L
authors: GL
authors: Lipscomb
authors: Dept. of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, United States.
authors: Gerrit J
authors: GJ
authors: Schut
authors: Dept. of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, United States.
authors: Matthew W
authors: MW
authors: Keller
authors: Dept. of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, United States.
authors: Michael W W
authors: MWW
authors: Adams
authors: Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, United States. Electronic address: rmkelly@ncsu.edu.
authors: Robert M
authors: RM
authors: Kelly
mesh_terms: D001105:Archaea / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D000071825:Extremophiles / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism*; D007700:Kinetics; D019344:Lactic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D008657:Metabolic Clearance Rate; D064688:Metabolic Flux Analysis / Q000379:methods*; D053858:Metabolic Networks and Pathways / Q000502:physiology*; D008954:Models, Biological; D015398:Signal Transduction / Q000502:physiology; D016943:Sulfolobaceae / Q000378:metabolism*
chemical_list: D006885:Hydroxybutyrates; D002245:Carbon Dioxide; C111420:4-hydroxybutyric acid; D019344:Lactic Acid; C031601:hydracrylic acid
keywords: 3-hydroxypropionate; 4-hydroxybutyrate; CO(2) fixation; Metallosphaera sedula