Characterization of benzoyl coenzyme A biosynthesis genes in the enterocin-producing bacterium "Streptomyces maritimus".
The novel benzoyl coenzyme A (benzoyl-CoA) biosynthesis pathway in "Streptomyces maritimus" was investigated through a series of target-directed mutations. Genes involved in benzoyl-CoA formation were disrupted through single-crossover homologous recombination, and the resulting mutants were analyzed for their ability to biosynthesize the benzoyl-CoA-primed polyketide antibiotic enterocin. Inactivation of the unique phenylalanine ammonia-lyase-encoding gene encP was previously shown to be absolutely required for benzoyl-CoA formation in "S. maritimus". The fatty acid beta-oxidation-related genes encH, -I, and -J, on the other hand, are necessary but not required. In each case, the yield of benzoyl-CoA-primed enterocin dropped below wild-type levels. We attribute the reduced benzoyl-CoA formation in these specific mutants to functional substitution and cross-talk between the products of genes encH, -I, and -J and the enzyme homologues of primary metabolism. Disruption of the benzoate-CoA ligase encN gene did not perturb enterocin production, however, demonstrating that encN is extraneous and that benzoic acid is not a pathway intermediate. EncN rather serves as a substitute pathway for utilizing exogenous benzoic acid. These experiments provide further support that benzoyl-CoA is formed in a novel bacterial pathway that resembles the eukaryotic assembly of benzoyl-CoA from phenylalanine via a beta-oxidative path.
Xiang
Longkuan
L
College of Pharmacy, Department of Chemistry, University of Arizona, Tucson 85721, USA.
Moore
Bradley S
BS
D000214:Acyl Coenzyme A / Q000096:biosynthesis* / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D001952:Bridged-Ring Compounds / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D010649:Phenylalanine / Q000378:metabolism; D011995:Recombination, Genetic; D013302:Streptomyces / Q000201:enzymology*
D000214:Acyl Coenzyme A; D001426:Bacterial Proteins; D001952:Bridged-Ring Compounds; D010649:Phenylalanine; C012306:enterocin; C037817:benzoyl-coenzyme A