Examining the contribution of a dA+dT element to the conformation of Escherichia coli integration host factor-DNA complexes

Nucleic Acids Res. 1996 May 1;24(9):1780-6. doi: 10.1093/nar/24.9.1780.


DNA binding proteins that induce structural changes in DNA are common in both prokaryotes and eukaryotes. Integration host factor (IHF) is a multi-functional DNA binding and bending protein of Escherichia coli that can mediate protein-protein and protein-DNA interactions by bending DNA. Previously we have shown that the presence of a dA+dT element 5'-proximal to an IHF consensus sequence can affect the binding of IHF to a particular site. In this study the contribution of various sequence elements to the formation of IHF-DNA complexes was examined. We show that IHF bends DNA more when it binds to a site containing a dA+dT element upstream of its core consensus element than to a site lacking a dA+dT element. We demonstrate that IHF can be specifically crosslinked to DNA with binding sites either containing or lacking this dA+dT element. These results indicate the importance of flanking DNA and a dA+dT element in the binding and bending of a site by IHF.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Attachment Sites, Microbiological
  • Bacterial Proteins / chemistry*
  • Base Composition
  • Base Sequence
  • Binding Sites
  • Cross-Linking Reagents
  • DNA, Recombinant / chemistry
  • DNA, Recombinant / genetics
  • DNA-Binding Proteins / chemistry*
  • Escherichia coli / chemistry
  • Integration Host Factors
  • Molecular Sequence Data
  • Nucleic Acid Conformation*
  • Oligodeoxyribonucleotides / chemistry*
  • Oligodeoxyribonucleotides / genetics
  • Poly dA-dT / chemistry*
  • Poly dA-dT / genetics
  • Recombination, Genetic / genetics
  • Ultraviolet Rays


  • Bacterial Proteins
  • Cross-Linking Reagents
  • DNA, Recombinant
  • DNA-Binding Proteins
  • Integration Host Factors
  • Oligodeoxyribonucleotides
  • Poly dA-dT