Gatekeeping versus promiscuity in the early stages of the andrimid biosynthetic assembly line

ACS Chem Biol. 2008 Sep 19;3(9):542-54. doi: 10.1021/cb800085g. Epub 2008 Jul 25.

Abstract

The antibiotic andrimid, a nanomolar inhibitor of bacterial acetyl coenzyme A carboxylase, is generated on an unusual polyketide/nonribosomal peptide enzyme assembly line in that all thiolation (T) domains/small-molecule building stations are on separate proteins. In addition, a transglutaminase homologue is used to condense andrimid building blocks together on the andrimid assembly line. The first two modules of the andrimid assembly line yields an octatrienoyl-beta-Phe-thioester tethered to the AdmI T domain, with amide bond formation carried out by a free-standing transglutaminase homologue AdmF. Analysis of the aminomutase AdmH reveals its specific conversion from l-Phe to (S)-beta-Phe, which in turn is activated by AdmJ and ATP to form (S)-beta-Phe-aminoacyl-AMP. AdmJ then transfers the (S)-beta-Phe moiety to one of the free-standing T domains, AdmI, but not AdmA, which instead gets loaded with an octatrienoyl group by other enzymes. AdmF, the amide synthase, will accept a variety of acyl groups in place of the octatrienoyl donor if presented on either AdmA or AdmI. AdmF will also use either stereoisomer of phenylalanine or beta-Phe when presented on AdmA and AdmI, but not when placed on noncognate T domains. Further, we show the polyketide synthase proteins responsible for the polyunsaturated acyl cap can be bypassed in vitro with N-acetylcysteamine as a low-molecular-weight acyl donor to AdmF and also in vivo in an Escherichia coli strain bearing the andrimid biosynthetic gene cluster with a knockout in admA.

Publication types

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

MeSH terms

  • Acetyl-CoA Carboxylase / antagonists & inhibitors
  • Amides / metabolism
  • Aminoacylation
  • Enzyme Inhibitors / metabolism*
  • Phenylalanine / metabolism
  • Polyenes / metabolism
  • Pyrroles / metabolism
  • Succinimides / metabolism
  • Transglutaminases / metabolism

Substances

  • Amides
  • Enzyme Inhibitors
  • Polyenes
  • Pyrroles
  • Succinimides
  • moiramide B
  • andrimid
  • Phenylalanine
  • Transglutaminases
  • Acetyl-CoA Carboxylase