title: A 12-cistron Escherichia coli operon (hyf) encoding a putative proton-translocating formate hydrogenlyase system.
abstract: The nucleotide sequence has been determined for a twelve-gene operon of Escherichia coli designated the hyf operon (hyfABCDEFGHIR-focB). The hyf operon is located at 55.8-56.0 min and encodes a putative nine-subunit hydrogenase complex (hydrogenase four or Hyf), a potential formate- and sigma 54-dependent transcriptional activator, HyfR (related to FhlA), and a possible formate transporter, FocB (related to FocA). Five of the nine Hyf-complex subunits are related to subunits of both the E. coli hydrogenase-3 complex (Hyc) and the proton-translocating NADH:quinone oxidoreductases (complex I and Nuo), whereas two Hyf subunits are related solely to NADH:quinone oxidoreductase subunits. The Hyf components include a predicted 523 residue [Ni-Fe] hydrogenase (large subunit) with an N-terminus (residues 1-170) homologous to the 30 kDa or NuoC subunit of complex I. It is proposed that Hyf, in conjunction with formate dehydrogenase H (Fdh-H), forms a hitherto unrecognized respiration-linked proton-translocating formate hydrogenlyase (FHL-2). It is likely that HyfR acts as a formate-dependent regulator of the hyf operon and that FocB provides the Hyf complex with external formate as substrate.
authors.affiliation: The Krebs Institute, Department of Molecular Biology & Biotechnology, Western Bank, Firth Court, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Simon C
authors.initials: SC
authors.lastname: Andrews
authors.affiliation: The Centre for Metalloprotein Spectroscopy & Biology, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
authors.forename: Ben C
authors.initials: BC
authors.lastname: Berks
authors.affiliation: The Sanger Centre, Hinxton Hall, Hinxton, Cambridge CB10 1SB, UK.
authors.forename: Joseph
authors.initials: J
authors.lastname: McClay
authors.affiliation: The Sanger Centre, Hinxton Hall, Hinxton, Cambridge CB10 1SB, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ambler
authors.affiliation: The Krebs Institute, Department of Molecular Biology & Biotechnology, Western Bank, Firth Court, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Quail
authors.affiliation: The Krebs Institute, Department of Molecular Biology & Biotechnology, Western Bank, Firth Court, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Golby
authors.affiliation: The Krebs Institute, Department of Molecular Biology & Biotechnology, Western Bank, Firth Court, University of Sheffield, Sheffield S10 2TN, UK.
authors.forename: John R
authors.initials: JR
authors.lastname: Guest
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005560:Formate Dehydrogenases / Q000737:chemistry / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics*; D006864:Hydrogenase / Q000737:chemistry / Q000235:genetics*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D008956:Models, Chemical; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics*; D016366:Open Reading Frames / Q000235:genetics; D009876:Operon / Q000235:genetics*; D017433:Protein Structure, Secondary; D011522:Protons; D015183:Restriction Mapping; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D011522:Protons; D006864:Hydrogenase; D005560:Formate Dehydrogenases; C054017:formate hydrogenlyase