Expression and regulation of a silent operon, hyf, coding for hydrogenase 4 isoenzyme in Escherichia coli

J Bacteriol. 2004 Jan;186(2):580-7. doi: 10.1128/JB.186.2.580-587.2004.

Abstract

On the basis of hyf-lacZ fusion studies, the hyf operon of Escherichia coli, noted for encoding the fourth hydrogenase isoenzyme (HYD4), is not expressed at a significant level in a wild-type strain. However, mutant FhlA proteins (constitutive activators of the hyc-encoded hydrogenase 3 isoenzyme) activated hyf-lacZ. HyfR, an FhlA homolog encoded by the hyfR gene present at the end of the hyf operon, also activated transcription of hyf-lacZ but did so only when hyfR was expressed from a heterologous promoter. The HYD4 isoenzyme did not substitute for HYD3 in H(2) production. Optimum expression of hyf-lacZ required the presence of cyclic AMP receptor protein-cyclic AMP complex and anaerobic conditions when HyfR was the activator.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerobiosis
  • Base Sequence
  • Cyclic AMP / physiology
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Escherichia coli / growth & development
  • Escherichia coli Proteins
  • Formates / pharmacology
  • Gene Expression Regulation, Bacterial*
  • Hydrogenase / genetics*
  • Molecular Sequence Data
  • Molybdenum / pharmacology
  • Operon
  • Transcription, Genetic

Substances

  • Escherichia coli Proteins
  • Formates
  • formic acid
  • molybdate
  • Molybdenum
  • Cyclic AMP
  • Hydrogenase
  • hydrogenase 4, E coli