Sequence-specific changes in the metal site of ferric bleomycin induced by the binding of DNA

J. W. Sam, S. Takahashi, I. Lippai, J. Peisach, D. L. Rousseau

研究成果: Article査読

28 被引用数 (Scopus)


The binding of the iron complex of the antineoplastic glycopeptide bleomycin A2 (Fe-BLM) to calf thymus DNA and the self-complementary oligonucleotides d(CGCGCG) and d(ATATAT) has been studied using optical, EPR, and resonance Raman spectroscopies. An increase in the intensity of the bands at 365 and 384 nm is observed in the optical spectrum of Fe(III)-BLM when the drug binds to either oligonucleotide. However, in the presence of phosphate, this increase is observed only with d(CGCGCG) and not with d(ATATAT). In addition, the g(max) feature in the EPR spectrum of low spin Fe(III)-BLM is narrowed in a way suggesting a reduction of possible conformers that the drug can achieve when it is bound to d(CGCGCG) or to calf thymus DNA but not when bound to d(ATATAT). When Fe(III)-BLM is bound to d(CGCGCG), changes in the resonance Raman spectrum of the metal drug complex suggest conformational changes in three of the ligands to iron: the β-hydroxyhistidyl amide, the pyrimidine, and the axial hydroxide. In addition, the Fe-OH band undergoes narrowing, again consistent, with the reduction of conformers of the drug. No such resonance Raman changes are observed upon binding to d(ATATAT). The changes in the pyrimidine modes upon binding d(CGCGCG) to the drug are consistent with a recently proposed model (Wu, W., Vanderwall, D. E., Turner, C. J., Kozarich, J. W., and Stubbe, J. (1996) J. Am. Chem. Soc. 118, 1281- 1294) of DNA recognition by activated bleomycin, HOO-Fe(III)BLM, in which the pyrimidine moiety of the drug is important for the preferential cleavage of 5'-GpPy-3' sequences.

ジャーナルJournal of Biological Chemistry
出版ステータスPublished - 1998 6月 26

ASJC Scopus subject areas

  • 生化学
  • 分子生物学
  • 細胞生物学


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