Overproduction and characterization of the iclR gene product of Escherichia coli K-12 and comparison with that of Salmonella typhimurium LT2.
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.
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Institut de Biologie et Chimie des Protéines, C.N.R.S., Université de Lyon, France.
Cortay
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JC
Old
I G
IG
Galinier
A
A
Richaud
C
C
Saint Girons
I
I
Cozzone
A J
AJ
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
D000085:Acetates; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C067479:IclR protein, E coli