Acidic phospholipids directly inhibit DNA binding of mammalian DNA topoisomerase I

Hiro omi Tamura, Yoji Ikegami, Katsuhiro Ono, Kazuhisa Sekimizu, Toshiwo Andoh

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


Inhibition of mammalian DNA topoisomerase I by phospholipids was investigated using purified enzyme. Acidic phospholipids inhibited the DNA relaxation activity of topoisomerase I whereas neutral phospholipid, phosphatidylethanolamine, did not. Accumulation of a protein-DNA cleavable complex, an intermediate which is known to accumulate upon inhibition by a specific inhibitor camptothecin, did not occur. The filter binding assay revealed that the DNA binding activity of the enzyme was inhibited by acidic phospholipids. Moreoever, direct binding of phosphatidylglycerol to topoisomerase I was demonstrated. These results indicated that the inhibitory effect of acidic phospholipids on topoisomerase I was due to the loss of the DNA binding of the enzyme as a result of direct interaction between phospholipids and the enzyme.

Original languageEnglish
Pages (from-to)151-154
Number of pages4
JournalFEBS Letters
Issue number1
Publication statusPublished - 1990 Feb 12
Externally publishedYes


  • Phospholipid
  • Topoisomerase I

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology


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