Assignment of functional amino acids around the active site of human DNA topoisomerase IIα

Y. Okada, Y. Ito, A. Kikuchi, Y. Nimura, S. Yoshida, M. Suzuki

研究成果: ジャーナルへの寄稿学術論文査読

18 被引用数 (Scopus)

抄録

An expression library for active site mutants of human topoisomerase IIα (TOP2α) was constructed by replacing the sequence encoding residues 793-808 with a randomized oligonucleotide cassette. This plasmid library was transformed into a temperature-sensitive yeast strain (top2-1), and viable transformants were selected at the restrictive temperature. Among the active TOP2α mutants, no substitution was allowed at Tyr805, the 5' anchor of the cleaved DNA, and only conservative substitutions were allowed at Leu794, Asp797, Ala801, and Arg804. Thus, these 5 residues are critical for human TOP2α activity, and the remaining mutagenized residues are less critical for function. Using the x-ray crystal structure of yeast TOP2 as a structural model, it can be deduced that these 5 functionally important residues lie in a plane. One of the possible functions of this plane may be that it interacts with the DNA substrate upon catalysis. The side chains of Ser803 and Lys798, which confer drug resistance, lie adjacent to this plane.

本文言語英語
ページ(範囲)24630-24638
ページ数9
ジャーナルJournal of Biological Chemistry
275
32
DOI
出版ステータス出版済み - 11-08-2000
外部発表はい

All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学
  • 細胞生物学

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