title: Functional characterization of beta-ketoacyl-ACP reductase (FabG) from Plasmodium falciparum.
abstract: The malaria parasite, Plasmodium falciparum, unlike its human host, utilizes type II fatty acid synthesis, in which steps of fatty acid biosynthesis are catalyzed by independent enzymes. Due to this difference, the enzymes of this pathway are a potential target of newer antimalarials. Here we report the functional characterization of Plasmodium FabG expressed in Escherichia coli. The purified recombinant FabG from P. falciparum is soluble and active. The K(m) of the enzyme for acetoacetyl-CoA was estimated to be 75 microM with a V(max) of 0.0054 micromol/min/ml and a k(cat) value of 0.014s(-1). NADPH exhibited negative cooperativity for its interaction with FabG. We have also modeled P. falciparum FabG using Brassica napus FabG as the template. This model provides a structural rationale for the specificity of FabG towards its cofactor, NADPH.
authors.affiliation: Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
authors.forename: Smitha
authors.initials: S
authors.lastname: Pillai
authors.forename: Chitra
authors.initials: C
authors.lastname: Rajagopal
authors.forename: Mili
authors.initials: M
authors.lastname: Kapoor
authors.forename: Gyanendra
authors.initials: G
authors.lastname: Kumar
authors.forename: Aditi
authors.initials: A
authors.lastname: Gupta
authors.forename: Namita
authors.initials: N
authors.lastname: Surolia
mesh_terms: D000429:Alcohol Oxidoreductases / Q000096:biosynthesis* / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D029688:Brassica napus / Q000378:metabolism; D003001:Cloning, Molecular; D003065:Coenzyme A / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005822:Genetic Vectors; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009249:NADP / Q000378:metabolism / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000201:enzymology*; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: D005227:Fatty Acids; D020033:Protein Isoforms; D009249:NADP; D000429:Alcohol Oxidoreductases; C023744:acetoacetyl-CoA reductase; D003065:Coenzyme A