Functional replacement of the faba and fabb proteins of Escherichia coli fatty acid synthesis by Enterococcus faecalis FabZ and FabF homologues

Haihong Waag, John E. Cronan

Research output: Contribution to journalArticlepeer-review

Abstract

The anaerobic unsaturated fatty acid synthetic pathway of Escherichia coli requires two specialized proteins, FabA and FabB. However, the fabA and fabB genes are found only in the Gram-negative α- and γ-proteobacteria, and thus other anaerobic bacteria must synthesize these acids using different enzymes. We report that the Gram-positive bacterium Enterococcus faecalis encodes a protein, annotated as FabZ1, that functionally replaces the E. coli FabA protein, although the sequence of this protein aligns much more closely with E. coli FabZ, a protein that plays no specific role in unsaturated fatty acid synthesis. Therefore E. faecalis FabZ1 is a bifunctional dehydratase/isomerase, an enzyme activity heretofore confined to a group of Gram-negative bacteria. The FabZ2 protein is unable to replace the function of E. coli FabZ, although FabZ2, a second E. faecalis FabZ homologue, has this ability. Moreover, an E. faecalis FabF homologue (FabF1) was found to replace the function of E. coli FabB, whereas a second FabF homologue was inactive. From these data it is clear that bacterial fatty acid biosynthetic pathways cannot be deduced solely by sequence comparisons.

Original languageEnglish (US)
Pages (from-to)34489-34495
Number of pages7
JournalJournal of Biological Chemistry
Volume279
Issue number33
DOIs
StatePublished - Aug 13 2004

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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