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Arylstibonic acids: Novel inhibitors and activators of human topoisomerase IB

  1. Author:
    Kim, H.
    Cardellina, J. H.
    Akee, R.
    Champoux, J. J.
    Stivers, J. T.
  2. Author Address

    Kim, Hyeongnam, Stivers, James T.] Johns Hopkins Univ, Sch Med, Dept Pharmacol & Mol Sci, Baltimore, MD 21205 USA. [Cardellina, John H., II] NCI, Screening Technol Branch, Frederick, MD 21702 USA. [Akee, Rhone] SAIC Frederick Inc, Nat Prod Support Grp, Frederick, MD 21702 USA. [Champoux, James J.] Univ Washington, Dept Microbiol, Sch Med, Seattle, WA 98195 USA.
    1. Year: 2008
  1. Journal: Bioorganic Chemistry
    1. 36
    2. 4-6
    3. Pages: 190-197
  2. Type of Article: Article
  1. Abstract:

    Human topoisomerase IB (hTopo) forms a covalent phosphotyrosyl linkage with the DNA backbone, and controls genomic DNA topology by relaxing DNA supercoils during the Processes of DNA replication, transcription, chromosome condensation and decondensation. The essential role of hTopo in these processes has made it a preeminent anticancer drug target. We have screened a small library of arylstibonic acids for their effects on plasmid supercoil relaxation catalyzed by hTopo. Despite the similar Structures of the library compounds, some compounds were found to be effective competitive inhibitors, and others, nonessential activators. Some arylstibonic acids show selectivity in their action against hTopo and the related enzyme from poxvirus (vTopo). Structure-activity relationships and structural modeling suggest that competitive inhibition may result from positioning of the negatively charged stibonic acid and carboxylate groups of the inhibitors into DNA phosphate binding pockets on hTopo. The hTopo activators act by a surprising allosteric mechanism without interfering with DNA binding or binding of the widely used hTopo poison camptothecin. Arylstibonic acid competitive inhibitors may become useful small molecules for elucidating the cellular functions of hTopo. (C) 2008 Elsevier Inc. All rights reserved.

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External Sources

  1. PMID: 18508107

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