RT Journal Article SR Electronic(1) A1 Andrews, Simon C. A1 Berks, Ben C. A1 McClay, Joseph A1 Ambler, Andrew A1 Quail, Michael A. A1 Golby, Paul A1 Guest, John R.YR 1997 T1 A 12-cistron Escherichia coli operon (hyf) encoding a putative proton-translocating formate hydrogenlyase system JF Microbiology, VO 143 IS 11 SP 3633 OP 3647 DO https://doi.org/10.1099/00221287-143-11-3633 PB Microbiology Society, SN 1465-2080, AB 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 σ54dependent 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., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-143-11-3633