Visualization of the bent helix in kinetoplast DNA by electron microscopy

Jack Griffith, Michael Bleyman, Carol A. Rauch, Peter A. Kitchin, Paul T. Englund

Research output: Contribution to journalArticlepeer-review

179 Scopus citations


Kinetoplast DNA minicircles from the trypanosomatid Crithidia fasciculata contain a segment of ∼200 bp which is probably more highly bent than any other DNA previously studied. Electron microscopy (EM) of relaxed minicircles (2.5 kb) revealed 200-300 bp loops within the larger circles, and the loops could also be detected on full-length linear molecules. Examination by EM of a 219 bp cloned fragment which contains the bent helix revealed that up to 70% of the molecules appeared circular whether or not the ends were cohesive. In contrast, a 207 bp fragment from pBR322 showed no circles and the fragments in general appeared much straighter than the kinetoplast fragments. Treatment of the 219 bp bent kinetoplast fragment with the drug distamycin caused a striking reduction in curvature.

Original languageEnglish (US)
Pages (from-to)717-724
Number of pages8
Issue number5
StatePublished - Aug 29 1986

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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