In yeast, the whole metabolic pathway for making 16- and 18-carbon fatty acids is carried out by fatty acid synthase, a 2.6 megadalton molecular-weight macromolecular assembly containing six copies of all eight catalytic centers. We have determined its crystal structure, which illuminates how this enzyme is initially activated and then carries out multiple steps of synthesis in each of six ster...

HetN, a putative ketoacyl reductase, is required for heterocyst pattern maintenance in the filamentous cyanobacterium Anabaena sp. strain PCC 7120. The hetN gene, when present on a multicopy plasmid, is able to suppress heterocyst differentiation. Little is known about the biochemical properties of HetN. In the present study, we found that HetN could hydrolyze ATP or GTP in vitro, and that this...

A target of the anti-tuberculosis drugs isoniazid (INH) and ethionamide (ETH) has been shown to be an enoyl reductase, encoded by the inhA gene. The mabA (mycolic acid biosynthesis A) gene is located immediately upstream of inhA in Mycobacterium tuberculosis, Mycobacterium bovis and Mycobacterium smegmatis. The MabA protein from M. tuberculosis was expressed in Escherichia coli and shown to hav...

Medium-chain fatty acids (MCFAs, 4-12 carbons) are valuable as precursors to industrial chemicals and biofuels, but are not canonical products of microbial fatty acid synthesis. We engineered microbial production of the full range of even- and odd-chain-length MCFAs and found that MCFA production is limited by rapid, irreversible elongation of their acyl-ACP precursors. To address this limitati...

Secondary metabolites derived from benzoic acid (BA) are of central importance in the interactions of plants with pests, pathogens, and symbionts and are potentially important in plant development. Peroxisomal b-oxidation has recently been shown to contribute to BA biosynthesis in plants, but not all of the enzymes involved have been defined. In this report, we demonstrate that the peroxisomal ...

Isolates of the rice blast fungus Magnaporthe grisea that carry the gene encoding Avirulence Conferring Enzyme1 (ACE1) are specifically recognized by rice (Oryza sativa) cultivars carrying the resistance gene Pi33. This recognition enables resistant plants to activate a defense response. ACE1 was isolated by map-based cloning and encodes a putative hybrid between a polyketide synthase and a non...