Metal binding to modified bleomycins. Zinc and ferrous complexes with an acetylated bleomycin

Norman J. Oppenheimer, Luis O. Rodriguez, Sidney Hecht

Research output: Contribution to journalArticle

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Abstract

We have studied the DNA- and metal-binding properties of a bleomycin A2 derivative in which the α-amino group of the β-aminoalanine moiety has been N-acetylated. The modified antibiotic has been shown to be without activity in mediating the in vitro release of [3H]thymine from PM-2 DNA. Fluorescence experiments indicate that the degree of quenching by DNA of the bithiazole fluorescence is unaffected by N-acetylation of bleomycin. Furthermore, 1H NMR experiments demonstrate that N-acetylation does not alter the stoichiometry of metal binding. The Fe(II)-Ac-bleomycin A2 complex, however, has been found to be stable in the presence of both O2 and CO, and thus inactivation appears to be accounted for by the loss of the ability to bind and/or reduce O2. Comparison of the 1H NMR spectra of the Fe(II)-bleomycin and Fe(II)-Ac-bleomycin A2 complexes indicates that either a drastic reorganization of the ligands with respect to the central iron atom has occurred or that an altered spin state is stabilized. These experiments establish that the ability of bleomycin to cause DNA damage is sensitive to even minor structural alterations within the antibiotic.

Original languageEnglish (US)
Pages (from-to)4096-4103
Number of pages8
JournalBiochemistry
Volume19
Issue number17
StatePublished - 1980
Externally publishedYes

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Bleomycin
Zinc
Metals
Acetylation
DNA
Fluorescence
Nuclear magnetic resonance
Anti-Bacterial Agents
Thymine
Experiments
Carbon Monoxide
Stoichiometry
DNA Damage
Quenching
Iron
Ligands
Derivatives
Atoms
iron bleomycin
Proton Magnetic Resonance Spectroscopy

ASJC Scopus subject areas

  • Biochemistry

Cite this

Metal binding to modified bleomycins. Zinc and ferrous complexes with an acetylated bleomycin. / Oppenheimer, Norman J.; Rodriguez, Luis O.; Hecht, Sidney.

In: Biochemistry, Vol. 19, No. 17, 1980, p. 4096-4103.

Research output: Contribution to journalArticle

Oppenheimer, Norman J. ; Rodriguez, Luis O. ; Hecht, Sidney. / Metal binding to modified bleomycins. Zinc and ferrous complexes with an acetylated bleomycin. In: Biochemistry. 1980 ; Vol. 19, No. 17. pp. 4096-4103.
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