E. coli DNA binding protein HU forms nucleosomelike structure with circular double-stranded DNA

Cell. 1979 Jun;17(2):265-74. doi: 10.1016/0092-8674(79)90152-1.


The incubation of the E coli DNA binding protein HU with relaxed circular SV40 DNA in the presence of pure nicking-closing enzyme introduces up to 18 negative superhelical turns in the DNA molecules as measured by agarose gel electrophoresis. The maximal density of supercoiling is obtained at a HU-DNA mass ratio of 1. Reconstituted DNA-HU complexes prefixed with glutaraldehyde appear as condensed circular structures having an average of 14 "beads" per circular SV40 DNA molecule, with a "bead" diameter of 180 +/- 23 A. The circular SV40 DNA is condensed by a ratio of 2.0-2.5 relative to naked DNA. This is similar to the ratio (2.4) measured for chromatin formed by reassociation of relaxed SV40 DNA with the four core histones.

MeSH terms

  • Chromatin / metabolism
  • Chromatin / ultrastructure*
  • DNA Helicases / metabolism*
  • DNA, Superhelical / metabolism*
  • DNA, Viral / metabolism
  • Endonucleases / metabolism
  • Escherichia coli
  • Histones / metabolism
  • Isoelectric Point
  • Molecular Weight
  • Simian virus 40
  • Structure-Activity Relationship


  • Chromatin
  • DNA, Superhelical
  • DNA, Viral
  • Histones
  • Endonucleases
  • DNA Helicases