These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Metal binding to modified bleomycins. Zinc and ferrous complexes with an acetylated bleomycin.
    Author: Oppenheimer NJ, Rodriguez LO, Hecht SM.
    Journal: Biochemistry; 1980 Aug 19; 19(17):4096-103. PubMed ID: 6157406.
    Abstract:
    We have studied the DNA- and metal-binding properties of a bleomycin A2 derivative in which the alpha-amino group of the beta-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.
    [Abstract] [Full Text] [Related] [New Search]