H1 binding unwinds DNA: Evidence from topological assays

Maria Ivanchenko, Ahmed Hassan, Kensal Van Holde, Jordanka Zlatanova

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


The preference of the linker histones to bind to superhelical DNA in comparison with linear or relaxed molecules suggests that these proteins might, in turn, change the twist and/or writhe of DNA molecules upon binding. In order to explore such a possibility, we looked for changes in the linking number of plasmid pBR322 caused by H1 binding, using assays that involve nicking and resealing of DNA strands. Two types of enzymes were used, eukaryotic topoisomerase I and prokaryotic DNA ligase. The results revealed that H1 binding causes unwinding of the DNA, with the unwinding angle being approximately 10°. The globular domain of histone H1 is also capable of unwinding DNA, but to a lesser degree.

Original languageEnglish
Pages (from-to)32580-32585
Number of pages6
JournalJournal of Biological Chemistry
Issue number51
Publication statusPublished - 1996
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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