title: Cloning, nucleotide sequence and regulation of the Salmonella typhimurium pyrD gene encoding dihydroorotate dehydrogenase.
abstract: The Salmonella typhimurium pyrD gene encoding dihydroorotate dehydrogenase was cloned and sequenced. In total, a sequence of 1286 nucleotide pairs was determined wherein a single open-reading-frame of 1011 bp, encoding a polypeptide of 336 amino acids having 95% similarity with the Escherichia coli pyrD gene product, was identified. A region of hyphenated-dyad symmetry exists within the leader region affording the potential for the formation of a stable secondary structure in the 5' end of the transcript. Mutations from several regulatory mutants were located within the region of dyad symmetry which would impart changes in the transcript within the putative secondary structure, implicating the secondary structure in regulation. Primer extension analysis revealed multiple transcriptional start sites located six to nine nucleotides downstream from the Pribnow box, with the primary initiation site differing in repressing and derepressing growth conditions. The results are discussed in terms of a translational attenuation model for regulation of pyrD expression.
authors: Department of Chemistry, University of Regina, Canada.
authors: M M
authors: MM
authors: Frick
authors: J
authors: J
authors: Neuhard
authors: R A
authors: RA
authors: Kelln
mesh_terms: D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D000090722:Dihydroorotate Dehydrogenase; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005814:Genes, Viral; D008969:Molecular Sequence Data; D009154:Mutation; D010088:Oxidoreductases / Q000235:genetics*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010957:Plasmids; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D004269:DNA, Bacterial; D000090722:Dihydroorotate Dehydrogenase; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors