The binding of the cyclic AMP receptor protein to synthetic DNA sites containing permutations in the consensus sequence TGTGA

Biochem J. 1987 Aug 15;246(1):227-32. doi: 10.1042/bj2460227.


The binding of the cyclic AMP receptor protein (CRP) to symmetrical synthetic DNA-binding sites was investigated with a gel-retardation assay. A set of ten different sequences was employed, comprising all base permutations at positions 2, 4, and 5 of the consensus sequence 5'(TGTGA)3'. We show that: (i) CRP has a higher affinity for the completely symmetrical site than towards the lac wild-type site; (ii) base substitutions at position 2 lead to either a complete loss of specific CRP binding (G----C), a reduction in specific CRP binding (G----A) or only marginal effects on specific CRP binding (G----T); (iii) changes at position 4 abolish (G----C; G----A) or reduce (G----T) specific CRP binding; and (iv) base permutations at position 5 reduce specific CRP binding, but never completely abolish it. Thus position 4, and to a lesser extent position 2, in the DNA consensus sequence are the most crucial ones for specific binding by CRP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Composition
  • Base Sequence
  • Binding Sites
  • Carrier Proteins / metabolism*
  • Cyclic AMP Receptor Protein*
  • DNA / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Macromolecular Substances
  • Nucleic Acid Conformation
  • Receptors, Cyclic AMP / metabolism*


  • Carrier Proteins
  • Cyclic AMP Receptor Protein
  • Macromolecular Substances
  • Receptors, Cyclic AMP
  • DNA