A conserved and seemingly redundant Escherichia coli biotin biosynthesis gene expressed only during anaerobic growth

Xuejiao Song, John E. Cronan

Research output: Contribution to journalArticlepeer-review

Abstract

Biotin is an essential metabolic cofactor and de novo biotin biosynthetic pathways are widespread in microorganisms and plants. Biotin synthetic genes are generally found clustered into bio operons to facilitate tight regulation since biotin synthesis is a metabolically expensive process. Dethiobiotin synthetase (DTBS) catalyzes the penultimate step of biotin biosynthesis, the formation of 7,8-diaminononanoate (DAPA). In Escherichia coli, DTBS is encoded by the bio operon gene bioD. Several studies have reported transcriptional activation of ynfK a gene of unknown function, under anaerobic conditions. Alignments of YnfK with BioD have led to suggestions that YnfK has DTBS activity. We report that YnfK is a functional DTBS, although an enzyme of poor activity that is poorly expressed. Supplementation of growth medium with DAPA or substitution of BioD active site residues for the corresponding YnfK residues greatly improved the DTBS activity of YnfK. We confirmed that FNR activates transcriptional level of ynfK during anaerobic growth and identified the FNR binding site of ynfK. The ynfK gene is well conserved in γ-proteobacteria.

Original languageEnglish (US)
Pages (from-to)1315-1327
Number of pages13
JournalMolecular Microbiology
Volume116
Issue number5
DOIs
StatePublished - Nov 2021

Keywords

  • Escherichia coli
  • anaerobic growth
  • biotin synthesis
  • dethiobiotin synthetase

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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