title: YfcX enables medium-chain-length poly(3-hydroxyalkanoate) formation from fatty acids in recombinant Escherichia coli fadB strains.
abstract: Expression of Escherichia coli open reading frame yfcX is shown to be required for medium-chain-length polyhydroxyalkanoate (PHA(MCL)) formation from fatty acids in an E. coli fadB mutant. The open reading frame encodes a protein, YfcX, with significant similarity to the large subunit of multifunctional beta-oxidation enzymes. E. coli fadB strains modified to contain an inactivated copy of yfcX and to express a medium-chain-length synthase are unable to form PHA(MCL)s when grown in the presence of fatty acids. Plasmid-based expression of yfcX in the FadB(-) YfcX(-) PhaC(+) strain restores polymer formation. YfcX is shown to be a multifunctional enzyme that minimally encodes hydratase and dehydrogenase activities. The gene encoding YfcX is located downstream from yfcY, a gene encoding thiolase activity. Results of insertional inactivation studies and enzyme activity analyses suggest a role for yfcX in PHA monomer unit formation in recombinant E. coli fadB mutant strains. Further studies are required to determine the natural role of YfcX in the metabolism of E. coli.
authors.affiliation: Metabolix, Inc., Cambridge, Massachusetts 02142, USA. snell@metabolix.com
authors.forename: Kristi D
authors.initials: KD
authors.lastname: Snell
authors.forename: Feng
authors.initials: F
authors.lastname: Feng
authors.forename: Luhua
authors.initials: L
authors.lastname: Zhong
authors.forename: David
authors.initials: D
authors.lastname: Martin
authors.forename: Lara L
authors.initials: LL
authors.lastname: Madison
mesh_terms: D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering / Q000379:methods; D063991:Mitochondrial Trifunctional Protein; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D016366:Open Reading Frames / Q000235:genetics; D011091:Polyesters / Q000378:metabolism*; D011995:Recombination, Genetic
chemical_list: D029968:Escherichia coli Proteins; D005227:Fatty Acids; D009097:Multienzyme Complexes; D011091:Polyesters; C467046:YfcX protein, E coli; D063991:Mitochondrial Trifunctional Protein