The fused TrpEG from Streptomyces venezuelae is an anthranilate synthase, not a 2-amino-2-deoxyisochorismate [corrected] (ADIC) synthase

Ethn Dis. 2008 Spring;18(2 Suppl 2):S2-9-13.

Abstract

The chloramphenicol producer Streptomyces venezuelae contains an enzyme, SvTrpEG, that has a high degree of amino acid sequence similarity to the phenazine biosynthetic enzyme PhzE of certain species of Pseudomonas. PhzE has the sequence signature of an anthranilate synthase, but recent evidence indicates that it catalyzes the production of 2-amino-2-deoxyisochorismate [corrected] (ADIC), an intermediate in the two-step anthranilate synthase reaction, not anthranilate. In order to determine if SvTrpEG is likewise an ADIC synthase, we have cloned the gene for SvTrpEG, expressed the recombinant enzyme in Escherichia coli, and purified the enzyme. Analysis of the SvTrpEG-catalyzed reaction mixture using UV-visible spectrophotometry, fluorescence spectrometry, and high-performance liquid chromatography shows that the product of the reaction is anthranilate, not ADIC. Our results therefore reveal that, despite its sequence similarity to PhzE, SvTrpEG is an anthranilate synthase, not an ADIC synthase.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Anthranilate Synthase / genetics*
  • Anthranilate Synthase / metabolism
  • Base Sequence
  • Catalysis
  • Chorismic Acid / metabolism
  • Cloning, Molecular
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Genes, Bacterial / genetics*
  • Kinetics
  • Molecular Sequence Data
  • Plasmids / genetics
  • Polymerase Chain Reaction
  • Pseudomonas / enzymology
  • Pseudomonas / genetics
  • Salmonella / enzymology
  • Salmonella / genetics
  • Streptomyces / enzymology*
  • Streptomyces / genetics*
  • Thermodynamics
  • Transformation, Genetic

Substances

  • Anthranilate Synthase
  • Chorismic Acid