Scavenging of cytosolic octanoic acid by mutant LplA lipoate ligases allows growth of Escherichia coli strains lacking the LipB octanoyltransferase of lipoic acid synthesis

Fatemah A.M. Hermes, John E. Cronan

Research output: Contribution to journalArticlepeer-review

Abstract

The LipB octanoyltransferase catalyzes the first step of lipoic acid synthesis in Escherichia coli, transfer of the octanoyl moiety from octanoyl-acyl carrier protein to the lipoyl domains of the E2 subunits of the 2-oxoacid dehydrogenases of aerobic metabolism. Strains containing null mutations in lipB are auxotrophic for either lipoic acid or octanoic acid. We report the isolation of two spontaneously arising mutant strains that allow growth of lipB strains on glucose minimal medium; we determined that suppression was caused by single missense mutations within the coding sequence of the gene (lplA) that encodes lipoate-protein ligase. The LplA proteins encoded by the mutant genes have reduced Km values for free octanoic acid and thus are able to scavenge cytosolic octanoic acid for octanoylation of lipoyl domains.

Original languageEnglish (US)
Pages (from-to)6796-6803
Number of pages8
JournalJournal of bacteriology
Volume191
Issue number22
DOIs
StatePublished - Nov 2009

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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