Function of the loop residue Thr792 in human DNA topoisomerase IIα

Namiko Suda, Yoshiyuki Nakagawa, Akihiko Kikuchi, Masako Sawada, Yuko Takami, Hiro Omi Funahashi, Akimasa Nakao, Shonen Yoshida, Motoshi Suzuki

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3 Citations (Scopus)


We studied the mutation effect of one of the putative loop residues Thr792 in human DNA topoisomerase IIα (TOP2α). Thr792 mutants were expressed from high or low copy plasmids in a temperature sensitive yeast strain deficient in TOP2 (top2-1). When expressed from a high copy plasmid, mutants with small side chains complemented the yeast defect; however, from a low copy plasmid, only wild-type, Ser, and Cys substitution mutants complemented the yeast defect. Interestingly, at the permissive temperature other mutants (e.g., Val, Gly, and Glu substitutions) showed the dominant negative effect to the top2-1 allele, which was not observed by the control α4-helix mutants. T792E mutant was 10-fold less active than wild-type and the T792P had no decatenation activity in vitro. These results suggest that Thr792 in human TOP2α is involved in enzyme catalysis.

Original languageEnglish
Pages (from-to)46-51
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - 28-03-2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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