title: Nucleotide sequence of the FNR-regulated fumarase gene (fumB) of Escherichia coli K-12.
abstract: The nucleotide sequence of a 3,162-base-pair (bp) segment of DNA containing the FNR-regulated fumB gene, which encodes the anaerobic class I fumarase (FUMB) of Escherichia coli, was determined. The structural gene was found to comprise 1,641 bp, 547 codons (excluding the initiation and termination codons), and the gene product had a predicted Mr of 59,956. The amino acid sequence of FUMB contained the same number of residues as did that of the aerobic class I fumarase (FUMA), and there were identical amino acids at all but 56 positions (89.8% identity). There was no significant similarity between the class I fumarases and the class II enzyme (FUMC) except in one region containing the following consensus: Gly-Ser-Xxx-Ile-Met-Xxx-Xxx-Lys-Xxx-Asn. Some of the 56 amino acid substitutions must be responsible for the functional preferences of the enzymes for malate dehydration (FUMB) and fumarate hydration (FUMA). Significant similarities between the cysteine-containing sequence of the class I fumarases (FUMA and FUMB) and the mammalian aconitases were detected, and this finding further supports the view that these enzymes are all members of a family of iron-containing hydrolyases. The nucleotide sequence of a 1,142-bp distal sequence of an unidentified gene (genF) located upstream of fumB was also defined and found to encode a product that is homologous to the product of another unidentified gene (genA), located downstream of the neighboring aspartase gene (aspA).
authors.affiliation: Department of Microbiology, University of Sheffield, United Kingdom.
authors.forename: P J
authors.initials: PJ
authors.lastname: Bell
authors.forename: S C
authors.initials: SC
authors.lastname: Andrews
authors.forename: M N
authors.initials: MN
authors.lastname: Sivak
authors.forename: J R
authors.initials: JR
authors.lastname: Guest
mesh_terms: D000154:Aconitate Hydratase / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000648:ultrastructure; D001483:Base Sequence; D003001:Cloning, Molecular; D003062:Codon; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D005649:Fumarate Hydratase / Q000235:genetics*; D005796:Genes; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D012995:Solubility
chemical_list: D001426:Bacterial Proteins; D003062:Codon; D004269:DNA, Bacterial; D005649:Fumarate Hydratase; D000154:Aconitate Hydratase