Genetic studies on the promoter of malT, the gene that encodes the activator of the Escherichia coli maltose regulon

Res Microbiol. Nov-Dec 1991;142(9):937-42. doi: 10.1016/0923-2508(91)90003-s.


We report the construction of a chromosomal malT-lacZ gene fusion that is expressed under the control of the malT promoter in Escherichia coli K12. The resulting hybrid protein is soluble and stable in crude cellular extracts, which allowed us to measure very low levels of malTp activity. In this note, we confirm and extend previous observations on the regulation of malTp. We show that the promoter is 40-times less active in the absence of cAMP receptor protein (CRP) than in its presence, that CRP works by binding to the site centred at position -70.5, and that all of the elements necessary and sufficient for the regulation by CRP are located downstream from position -122.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Cyclic AMP / genetics
  • DNA-Binding Proteins*
  • Escherichia coli / genetics*
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial
  • In Vitro Techniques
  • Lac Operon / physiology
  • Promoter Regions, Genetic / genetics*
  • Recombinant Fusion Proteins / genetics*
  • Transcription Factors*
  • Transcription, Genetic / genetics


  • Bacterial Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • MalT protein, E coli
  • Recombinant Fusion Proteins
  • Transcription Factors
  • Cyclic AMP