title: High expression of the second lysine decarboxylase gene, ldc, in Escherichia coli WC196 due to the recognition of the stop codon (TAG), at a position which corresponds to the 33th amino acid residue of sigma38, as a serine residue by the amber suppressor, supD.
abstract: Escherichia coli WC196, which was obtained from the strain W3110 by nitrosoguanidine mutagenesis as an overproducer of lysine, produced approximately twenty times more cadaverine than did W3110, and had a twenty fold higher level of rpoS gene product, sigma38, than in W3110. Both WC196 and W3110 had a stop codon (TAG) in rpoS at position which corresponds to the 33th residue of sigma38 protein. In addition, WC196 but not W3110 had a mutation in the gene encoding Ser-tRNA (SerU), called, supD. Analysis of the amino acid sequence of a sigma38 preparation from WC196 showed that the 33th residue of sigma38 is a serine residue. The deltarpoS deltacadA mutant of E. coli W3110 harboring the plasmid containing rpoS, in which the TAG codon was converted to a TCG codon for serine-33 residue of sigma38, expressed a significant amount of Ldc and accumulated a large amount of sigma38. However, the deltarpoS deltacadA mutant of W3110 with the plasmid containing the intact rpoS from W3110 could synthesize neither sigma38 nor Ldc significantly.
authors.affiliation: Department of Molecular and Cell Biology, Graduate School, of Agricultural Science, Tohoku University, Sendai, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nagano
authors.forename: Y
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Kamio
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002262:Carboxy-Lyases / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D018388:Codon, Terminator; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D016153:Genes, Suppressor; D007700:Kinetics; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010957:Plasmids; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics*; D011994:Recombinant Proteins / Q000378:metabolism; D012808:Sigma Factor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D018388:Codon, Terminator; D012346:RNA, Transfer, Amino Acyl; D011994:Recombinant Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D002262:Carboxy-Lyases; C021520:lysine decarboxylase