PKSE biosynthesizes an enediyne core precursor from decarboxylative condensation of eight malonyl-CoAs. The KR domain of PKSE is responsible for iterative β-ketoreduction in each round of polyketide chain elongation. KRs from selected PKSEs were investigated in vitro with β-ketoacyl-SNACs as substrate mimics. Each of the KRs reduced the β-ketoacyl-SNACs stereoselectively, all affording the corr...

The DNA insert of plasmid pK52 contains the fadAB operon coding for the Escherichia coli fatty acid oxidation complex. Studies on the operon's structure and organization revealed that the initiator codon (ATG) of the structural gene for 3-ketoacyl-CoA thiolase, the fadA gene, is located 109 nucleotides 3' to the stop codon (TGA) of the fadB gene that encodes the alpha-subunit, a multifunctional...

The type II fatty acid synthase pathway of Plasmodium falciparum is a validated unique target for developing novel antimalarials because of its intrinsic differences from the type I pathway operating in humans. beta-Ketoacyl-acyl carrier protein reductase is the only enzyme of this pathway that has no isoforms and thus selective inhibitors can be developed for this player of the pathway. We rep...

Ketoacyl synthases (KSs) catalyze condensing reactions combining acyl-CoA or acylacyl carrier protein (ACP) with malonyl-CoA to form 3-ketoacyl-CoA, or with malonyl-ACP to form 3-ketoacyl-ACP. In each case the resulting acyl chain is two carbon atoms longer than before, and CO2 and either CoA or ACP are formed. KSs also join other activated molecules in the polyketide synthesis cycle. Our class...

Escherichia coli hosts expressing fabG of Pseudomonas aeruginosa showed 3-ketoacyl coenzyme A (CoA) reductase activity toward R-3-hydroxyoctanoyl-CoA. Furthermore, E. coli recombinants carrying the poly-3-hydroxyalkanoate (PHA) polymerase-encoding gene phaC in addition to fabG accumulated medium-chain-length PHAs (mcl-PHAs) from alkanoates. When E. coli fadB or fadA mutants, which are deficient...

Two classes of Escherichia coli unsaturated fatty acid auxotrophs, which are complementary both in vivo and in vitro, have been utilized to study unsaturated fatty acid synthesis. /3 Hydroxydecanoyl thioester dehydrase, which catalyzes the first committed reaction in the unsaturated fatty acid synthetic pathway, is defective in one class, fab A. The defect in the second class, fab B, was unknow...

The subunit locations of the five enzymes associated with the fatty acid oxidation complex from Escherichia coli were studied by immunotitration and chemical modification. Antibodies raised against the purified complex caused the parallel inhibitions of enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase, while slightly stimulating 3-ketoacyl-CoA thiolase. All five component enzymes of the ...

The 4'-phosphopantetheine of chicken liver fatty acid synthase was specifically labeled with the fluorescent substrate analog coenzyme A 6-[7-nitrobenz-2-oxa-1,3-diazol-4-yl]aminohexanoate at low salt concentrations. A serine at the active site of the thioesterase was specifically labeled with the fluorescent compounds 6-[7-nitrobenz-2-oxa-1,3-diazol-4-yl]aminopentylmethylphosphono fluoridate a...

Recently, we reported that the patterns of antibodies to Helicobacter pylori protein antigens in serum may be useful for screening patients at high risk for ulcers (P. Aucher et al., J. Clin. Microbiol. 36:931-936, 1998). Here we report the identification, by a combination of electrophoretic, immunochemical, and protein sequencing methods, of five antigens that correspond to this antibody patte...

The component enzymes of the chloroplast-associated, acyl carrier protein (ACP)-dependent, fatty acid synthetase (FAS-11) from Euglena gracilis have been independently examined by gel filtration chromatography of crude extracts from photoautotrophic cells. The acetyl coenzyme A:ACP transacylase, malonyl CoA:ACP transacylase, and /3-ketoacyl-ACP reductase activities were clearly resolved with a...