Overproduction and characterization of the iclR gene product of Escherichia coli K-12 and comparison with that of Salmonella typhimurium LT2

Gene. 1991 Jan 2;97(1):29-37. doi: 10.1016/0378-1119(91)90006-w.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / metabolism
  • Amino Acid Sequence
  • Bacterial Proteins / biosynthesis
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Cloning, Molecular
  • DNA, Bacterial / metabolism
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial
  • Genes, Regulator
  • Molecular Sequence Data
  • Operator Regions, Genetic
  • Operon
  • Repressor Proteins / biosynthesis
  • Repressor Proteins / genetics*
  • Repressor Proteins / metabolism
  • Restriction Mapping
  • Salmonella typhimurium / genetics*
  • Salmonella typhimurium / metabolism
  • Sequence Homology, Nucleic Acid
  • Transcription Factors*


  • Acetates
  • Bacterial Proteins
  • DNA, Bacterial
  • Escherichia coli Proteins
  • Repressor Proteins
  • Transcription Factors
  • IclR protein, E coli

Associated data

  • GENBANK/M34937
  • GENBANK/M63439
  • GENBANK/M63440
  • GENBANK/M63441
  • GENBANK/M63442
  • GENBANK/M63443
  • GENBANK/M63444
  • GENBANK/M63445
  • GENBANK/M63914
  • GENBANK/M74185
  • GENBANK/S75878