title: Nitrate-inducible formate dehydrogenase in Escherichia coli K-12. I. Nucleotide sequence of the fdnGHI operon and evidence that opal (UGA) encodes selenocysteine.
abstract: The fdnGHI operon of Escherichia coli encodes nitrate-inducible formate dehydrogenase. We report here the entire nucleotide sequence of fdnGHI. The sequence contains three open reading frames of sizes appropriate to encode the three subunits of formate dehydrogenase-N. fdnG contains an in-frame UGA codon that specifies selenocysteine incorporation, and the predicted amino acid sequence of FdnG shows similarity to two other bacterial formate dehydrogenase enzymes. FdnH contains 4 cysteine clusters typical of those found in iron-sulfur proteins. FdnG also contains a cysteine cluster. Evidence from sequence and spectral analyses suggest that FdnI encodes cytochrome bFdn556. Implications for the membrane topology of formate dehydrogenase-N and its mechanism of proton translocation are discussed.
authors.affiliation: Section of Microbiology, Cornell University, Ithaca, New York 14853-8101.
authors.forename: B L
authors.initials: BL
authors.lastname: Berg
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Heider
authors.forename: V
authors.initials: V
authors.lastname: Stewart
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003062:Codon / Q000235:genetics*; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D003573:Cytochrome b Group / Q000235:genetics*; D004790:Enzyme Induction; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D005560:Formate Dehydrogenases / Q000096:biosynthesis / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D005798:Genes, Bacterial / Q000187:drug effects; D005838:Genotype; D008969:Molecular Sequence Data; D009566:Nitrates / Q000494:pharmacology*; D009838:Oligodeoxyribonucleotides; D016366:Open Reading Frames; D009876:Operon; D016566:Organoselenium Compounds / Q000378:metabolism*; D010957:Plasmids; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015183:Restriction Mapping; D017279:Selenocysteine; D012689:Sequence Homology, Nucleic Acid; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D003062:Codon; D003573:Cytochrome b Group; D009566:Nitrates; D009838:Oligodeoxyribonucleotides; D016566:Organoselenium Compounds; D011993:Recombinant Fusion Proteins; D017279:Selenocysteine; C018256:cytochrome b556; D005560:Formate Dehydrogenases; D001616:beta-Galactosidase; D003545:Cysteine