title: Overproduction and characterization of the iclR gene product of Escherichia coli K-12 and comparison with that of Salmonella typhimurium LT2.
abstract: The iclR gene of Escherichia coli K-12, which encodes a regulatory protein (repressor) for the aceBAK operon, is located between that operon and metH in the 91-min region of the chromosome. The iclR gene was cloned and expressed in a coupled T7 RNA polymerase/promoter system and the gene product was identified by specific binding to a fragment containing the aceBAK operator region. The iclR gene product is a polypeptide of 274 amino acids (aa) with a calculated Mr of 29,741. Comparison of the deduced IclR aa sequence to that of Salmonella typhimurium revealed that the two IclR repressors exhibit 89% identity. A possible helix-turn-helix motif characteristic of DNA-binding proteins was found within the IclR sequence. A search in protein data banks revealed that IclR has a score of similarity of 43.7% with GylR, a transcriptional regulator of the glycerol operon of Streptomyces coelicolor.
authors.affiliation: Institut de Biologie et Chimie des Protéines, C.N.R.S., Université de Lyon, France.
authors.forename: D
authors.initials: D
authors.lastname: Nègre
authors.forename: J C
authors.initials: JC
authors.lastname: Cortay
authors.forename: I G
authors.initials: IG
authors.lastname: Old
authors.forename: A
authors.initials: A
authors.lastname: Galinier
authors.forename: C
authors.initials: C
authors.lastname: Richaud
authors.forename: I
authors.initials: I
authors.lastname: Saint Girons
authors.forename: A J
authors.initials: AJ
authors.lastname: Cozzone
mesh_terms: D000085:Acetates / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D009876:Operon; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D015183:Restriction Mapping; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors
chemical_list: D000085:Acetates; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C067479:IclR protein, E coli