Intra- and intermolecular strand transfer by HeLa DNA topoisomerase I.

B. D. Halligan, J. L. Davis, K. A. Edwards, Leroy-Fong Liu

研究成果: 雜誌貢獻文章

85 引文 斯高帕斯(Scopus)

摘要

The major type I DNA topoisomerase (topo I) has been purified from HeLa cell nuclei to a homogeneous, monomeric protein (Mr = 100,000). Similar to the nicking-closing enzyme (Mr = 67,000) from rat liver (Been, M. D., and Champoux, J. J. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 2883-2887), HeLa topo I has the following properties: (a) HeLa topo I breaks down single-stranded DNA to smaller fragments, each with an enzyme-linked 3'-phosphoryl end and a free 5'-OH end. This cleavage is not dependent upon protein denaturant or protease treatment. (b) HeLa topo I produces single-stranded DNA circles from linear single-stranded DNA. Such DNA circles are believed to be produced by the intramolecular cyclization of topo I-linked, single-stranded DNA fragments. (c) HeLa topo I-linked, single-stranded fragments (donors) can join covalently to double-stranded DNA possessing a 5'-OH group (acceptors). The donor is transferred to the 5'-OH end of the acceptor, independent of the position of the end (internal nick or end of linear DNA) or the configuration of the end (flush, 5'-protruding, or 5'-recessed end) of the acceptor. (d) HeLa topo I cleavage of single-stranded DNA is site-specific, but no special sequence at the ends of the acceptor molecule is apparently required for a successful heterologous strand transfer. These results suggest that HeLa topo I may be involved in DNA sequence rearrangements in addition to its possible role as a swivelase for transcription and replication.

原文英語
頁(從 - 到)3995-4000
頁數6
期刊Journal of Biological Chemistry
257
發行號7
出版狀態已發佈 - 四月 10 1982
對外發佈Yes

ASJC Scopus subject areas

  • Biochemistry

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  • 引用此

    Halligan, B. D., Davis, J. L., Edwards, K. A., & Liu, L-F. (1982). Intra- and intermolecular strand transfer by HeLa DNA topoisomerase I. Journal of Biological Chemistry, 257(7), 3995-4000.