Genes Encoding acyl-CoA Dehydrogenase (AcdH) Homologues From Streptomyces Coelicolor and Streptomyces Avermitilis Provide Insights Into the Metabolism of Small Branched-Chain Fatty Acids and Macrolide Antibiotic Production

Microbiology. 1999 Sep;145 ( Pt 9):2323-2334. doi: 10.1099/00221287-145-9-2323.


The cloning, using a PCR approach, of genes from both Streptomyces coelicolor and Streptomyces avermitilis encoding an acyl-CoA dehydrogenase (AcdH), putatively involved in the catabolism of branched-chain amino acids, is reported. The deduced amino acid sequences of both genes have a high similarity to prokaryotic and eukaryotic short-chain acyl-CoA dehydrogenases. When the S. coelicolor and S. avermitilis acyl-CoA dehydrogenase genes (acdH) were expressed in Escherichia coli, each of the AcdH flavoproteins was able to oxidize the branched-chain acyl-CoA derivatives isobutyryl-CoA, isovaleryl-CoA and cyclohexylcarbonyl-CoA, as well as the short straight-chain acyl-CoAs n-butyryl-CoA and n-valeryl-CoA in vitro. NMR spectral data confirmed that the oxidized product of isobutyryl-CoA is methacrylyl-CoA, which is the expected product at the acyl-CoA dehydrogenase step in the catabolism of valine in streptomycetes. Disruption of the S. avermitilis acdH produced a mutant unable to grow on solid minimal medium containing valine, isoleucine or leucine as sole carbon sources. Feeding studies with 13C triple-labelled isobutyrate revealed a significant decrease in the incorporation of label into the methylmalonyl-CoA-derived positions of avermectin in the acdH mutant. In contrast the mutation did not affect incorporation into the malonyl-CoA-derived positions of avermectin. These results are consistent with the acdH gene encoding an acyl-CoA dehydrogenase with a broad substrate specificity that has a role in the catabolism of branched-chain amino acids in S. coelicolor and S. avermitilis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acyl-CoA Dehydrogenase
  • Acyl-CoA Dehydrogenases / genetics*
  • Acyl-CoA Dehydrogenases / metabolism*
  • Amino Acid Sequence
  • Animals
  • Anti-Bacterial Agents / biosynthesis*
  • Chromatography, High Pressure Liquid
  • Cloning, Molecular
  • Electrophoresis, Polyacrylamide Gel
  • Fatty Acids / metabolism*
  • Gene Deletion
  • Humans
  • Ivermectin / analogs & derivatives
  • Ivermectin / metabolism
  • Macrolides
  • Molecular Sequence Data
  • Polymerase Chain Reaction / methods
  • Rats
  • Sequence Analysis, DNA
  • Streptomyces / enzymology
  • Streptomyces / genetics*


  • Anti-Bacterial Agents
  • Fatty Acids
  • Macrolides
  • Ivermectin
  • avermectin
  • Acyl-CoA Dehydrogenases
  • Acyl-CoA Dehydrogenase

Associated data

  • GENBANK/AF142581
  • GENBANK/AF143210